/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright (C) 2014 David Herrmann systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see . ***/ /* * Terminal Page/Line/Cell/Char Handling * This file implements page handling of a terminal. It is split into pages, * lines, cells and characters. Each object is independent of the next upper * object. * * The Terminal layer keeps each line of a terminal separate and dynamically * allocated. This allows us to move lines from main-screen to history-buffers * very fast. Same is true for scrolling, top/bottom borders and other buffer * operations. * * While lines are dynamically allocated, cells are not. This would be a waste * of memory and causes heavy fragmentation. Furthermore, cells are moved much * less frequently than lines so the performance-penalty is pretty small. * However, to support combining-characters, we have to initialize and cleanup * cells properly and cannot just release the underlying memory. Therefore, * cells are treated as proper objects despite being allocated in arrays. * * Each cell has a set of attributes and a stored character. This is usually a * single Unicode character stored as 32bit UCS-4 char. However, we need to * support Unicode combining-characters, therefore this gets more complicated. * Characters themselves are represented by a "term_char_t" object. It * should be treated as a normal integer and passed by value. The * surrounding struct is just to hide the internals. A term-char can contain a * base character together with up to 2 combining-chars in a single integer. * Only if you need more combining-chars (very unlikely!) a term-char is a * pointer to an allocated storage. This requires you to always free term-char * objects once no longer used (even though this is a no-op most of the time). * Furthermore, term-char objects are not ref-counted so you must duplicate them * in case you want to store it somewhere and retain a copy yourself. By * convention, all functions that take a term-char object will not duplicate * it but implicitly take ownership of the passed value. It's up to the caller * to duplicate it beforehand, in case it wants to retain a copy. * * If it turns out, that more than 2 comb-chars become common in specific * languages, we can try to optimize this. One idea is to ref-count allocated * characters and store them in a hash-table (like gnome's libvte3 does). This * way we will never have two allocated chars for the same content. Or we can * simply put two uint64_t into a "term_char_t". This will slow down operations * on systems that don't need that many comb-chars, but avoid the dynamic * allocations on others. * Anyhow, until we have proper benchmarks, we will keep the current code. It * seems to compete very well with other solutions so far. * * The page-layer is a one-dimensional array of lines. Considering that each * line is a one-dimensional array of cells, the page layer provides the * two-dimensional cell-page required for terminals. The page itself only * operates on lines. All cell-related operations are forwarded to the correct * line. * A page does not contain any cursor tracking. It only provides the raw * operations to shuffle lines and modify the page. */ #include #include #include #include "macro.h" #include "term-internal.h" #include "util.h" /* maximum UCS-4 character */ #define CHAR_UCS4_MAX (0x10ffff) /* mask for valid UCS-4 characters (21bit) */ #define CHAR_UCS4_MASK (0x1fffff) /* UCS-4 replacement character */ #define CHAR_UCS4_REPLACEMENT (0xfffd) /* real storage behind "term_char_t" in case it's not packed */ typedef struct term_character { uint8_t n; uint32_t codepoints[]; } term_character; /* * char_pack() takes 3 UCS-4 values and packs them into a term_char_t object. * Note that UCS-4 chars only take 21 bits, so we still have the LSB as marker. * We set it to 1 so others can distinguish it from pointers. */ static inline term_char_t char_pack(uint32_t v1, uint32_t v2, uint32_t v3) { uint64_t packed, u1, u2, u3; u1 = v1; u2 = v2; u3 = v3; packed = 0x01; packed |= (u1 & (uint64_t)CHAR_UCS4_MASK) << 43; packed |= (u2 & (uint64_t)CHAR_UCS4_MASK) << 22; packed |= (u3 & (uint64_t)CHAR_UCS4_MASK) << 1; return TERM_CHAR_INIT(packed); } #define char_pack1(_v1) char_pack2((_v1), CHAR_UCS4_MAX + 1) #define char_pack2(_v1, _v2) char_pack3((_v1), (_v2), CHAR_UCS4_MAX + 1) #define char_pack3(_v1, _v2, _v3) char_pack((_v1), (_v2), (_v3)) /* * char_unpack() is the inverse of char_pack(). It extracts the 3 stored UCS-4 * characters and returns them. Note that this does not validate the passed * term_char_t. That's the responsibility of the caller. * This returns the number of characters actually packed. This obviously is a * number between 0 and 3 (inclusive). */ static inline uint8_t char_unpack(term_char_t packed, uint32_t *out_v1, uint32_t *out_v2, uint32_t *out_v3) { uint32_t v1, v2, v3; v1 = (packed._value >> 43) & (uint64_t)CHAR_UCS4_MASK; v2 = (packed._value >> 22) & (uint64_t)CHAR_UCS4_MASK; v3 = (packed._value >> 1) & (uint64_t)CHAR_UCS4_MASK; if (out_v1) *out_v1 = v1; if (out_v2) *out_v2 = v2; if (out_v3) *out_v3 = v3; return (v1 > CHAR_UCS4_MAX) ? 0 : ((v2 > CHAR_UCS4_MAX) ? 1 : ((v3 > CHAR_UCS4_MAX) ? 2 : 3)); } /* cast a term_char_t to a term_character* */ static inline term_character *char_to_ptr(term_char_t ch) { return (term_character*)(unsigned long)ch._value; } /* cast a term_character* to a term_char_t */ static inline term_char_t char_from_ptr(term_character *c) { return TERM_CHAR_INIT((unsigned long)c); } /* * char_alloc() allocates a properly aligned term_character object and returns * a pointer to it. NULL is returned on allocation errors. The object will have * enough room for @n following UCS-4 chars. * Note that we allocate (n+1) characters and set the last one to 0 in case * anyone prints this string for debugging. */ static term_character *char_alloc(uint8_t n) { term_character *c; int r; r = posix_memalign((void**)&c, MAX(sizeof(void*), (size_t)2), sizeof(*c) + sizeof(*c->codepoints) * (n + 1)); if (r) return NULL; c->n = n; c->codepoints[n] = 0; return c; } /* * char_free() frees the memory allocated via char_alloc(). It is safe to call * this on any term_char_t, only allocated characters are freed. */ static inline void char_free(term_char_t ch) { if (term_char_is_allocated(ch)) free(char_to_ptr(ch)); } /* * This appends @append_ucs4 to the existing character @base and returns * it as a new character. In case that's not possible, @base is returned. The * caller can use term_char_same() to test whether the returned character was * freshly allocated or not. */ static term_char_t char_build(term_char_t base, uint32_t append_ucs4) { /* soft-limit for combining-chars; hard-limit is currently 255 */ const size_t climit = 64; term_character *c; uint32_t buf[3], *t; uint8_t n; /* ignore invalid UCS-4 */ if (append_ucs4 > CHAR_UCS4_MAX) return base; if (term_char_is_null(base)) { return char_pack1(append_ucs4); } else if (!term_char_is_allocated(base)) { /* unpack and try extending the packed character */ n = char_unpack(base, &buf[0], &buf[1], &buf[2]); switch (n) { case 0: return char_pack1(append_ucs4); case 1: if (climit < 2) return base; return char_pack2(buf[0], append_ucs4); case 2: if (climit < 3) return base; return char_pack3(buf[0], buf[1], append_ucs4); default: /* fallthrough */ break; } /* already fully packed, we need to allocate a new one */ t = buf; } else { /* already an allocated type, we need to allocate a new one */ c = char_to_ptr(base); t = c->codepoints; n = c->n; } /* bail out if soft-limit is reached */ if (n >= climit) return base; /* allocate new char */ c = char_alloc(n + 1); if (!c) return base; memcpy(c->codepoints, t, sizeof(*t) * n); c->codepoints[n] = append_ucs4; return char_from_ptr(c); } /** * term_char_set() - Reset character to a single UCS-4 character * @previous: term-char to reset * @append_ucs4: UCS-4 char to set * * This frees all resources in @previous and re-initializes it to @append_ucs4. * The new char is returned. * * Usually, this is used like this: * obj->ch = term_char_set(obj->ch, ucs4); * * Returns: The previous character reset to @append_ucs4. */ term_char_t term_char_set(term_char_t previous, uint32_t append_ucs4) { char_free(previous); return char_build(TERM_CHAR_NULL, append_ucs4); } /** * term_char_merge() - Merge UCS-4 char at the end of an existing char * @base: existing term-char * @append_ucs4: UCS-4 character to append * * This appends @append_ucs4 to @base and returns the result. @base is * invalidated by this function and must no longer be used. The returned value * replaces the old one. * * Usually, this is used like this: * obj->ch = term_char_merge(obj->ch, ucs4); * * Returns: The new merged character. */ term_char_t term_char_merge(term_char_t base, uint32_t append_ucs4) { term_char_t ch; ch = char_build(base, append_ucs4); if (!term_char_same(ch, base)) term_char_free(base); return ch; } /** * term_char_dup() - Duplicate character * @ch: character to duplicate * * This duplicates a term-character. In case the character is not allocated, * nothing is done. Otherwise, the underlying memory is copied and returned. You * need to call term_char_free() on the returned character to release it again. * On allocation errors, a replacement character is returned. Therefore, the * caller can safely assume that this function always succeeds. * * Returns: The duplicated term-character. */ term_char_t term_char_dup(term_char_t ch) { term_character *c, *newc; if (!term_char_is_allocated(ch)) return ch; c = char_to_ptr(ch); newc = char_alloc(c->n); if (!newc) return char_pack1(CHAR_UCS4_REPLACEMENT); memcpy(newc->codepoints, c->codepoints, sizeof(*c->codepoints) * c->n); return char_from_ptr(newc); } /** * term_char_dup_append() - Duplicate tsm-char with UCS-4 character appended * @base: existing term-char * @append_ucs4: UCS-4 character to append * * This is similar to term_char_merge(), but it returns a separately allocated * character. That is, @base will stay valid after this returns and is not * touched. In case the append-operation fails, @base is duplicated and * returned. That is, the returned char is always independent of @base. * * Returns: Newly allocated character with @append_ucs4 appended to @base. */ term_char_t term_char_dup_append(term_char_t base, uint32_t append_ucs4) { term_char_t ch; ch = char_build(base, append_ucs4); if (term_char_same(ch, base)) ch = term_char_dup(base); return ch; } /** * term_char_resolve() - Retrieve the UCS-4 string for a term-char * @ch: character to resolve * @s: storage for size of string or NULL * @b: storage for string or NULL * * This takes a term-character and returns the UCS-4 string associated with it. * In case @ch is not allocated, the string is stored in @b (in case @b is NULL * static storage is used). Otherwise, a pointer to the allocated storage is * returned. * * The returned string is only valid as long as @ch and @b are valid. The string * is zero-terminated and can safely be printed via long-character printf(). * The length of the string excluding the zero-character is returned in @s. * * This never returns NULL. Even if the size is 0, this points to a buffer of at * least a zero-terminator. * * Returns: The UCS-4 string-representation of @ch, and its size in @s. */ const uint32_t *term_char_resolve(term_char_t ch, size_t *s, term_charbuf_t *b) { static term_charbuf_t static_b; term_character *c; uint32_t *cache; size_t len; if (b) cache = b->buf; else cache = static_b.buf; if (term_char_is_null(ch)) { len = 0; cache[0] = 0; } else if (term_char_is_allocated(ch)) { c = char_to_ptr(ch); len = c->n; cache = c->codepoints; } else { len = char_unpack(ch, &cache[0], &cache[1], &cache[2]); cache[len] = 0; } if (s) *s = len; return cache; } /** * term_char_lookup_width() - Lookup cell-width of a character * @ch: character to return cell-width for * * This is an equivalent of wcwidth() for term_char_t. It can deal directly * with UCS-4 and combining-characters and avoids the mess that is wchar_t and * locale handling. * * Returns: 0 for unprintable characters, >0 for everything else. */ unsigned int term_char_lookup_width(term_char_t ch) { term_charbuf_t b; const uint32_t *str; unsigned int max; size_t i, len; int r; max = 0; str = term_char_resolve(ch, &len, &b); for (i = 0; i < len; ++i) { /* * Oh god, C99 locale handling strikes again: wcwidth() expects * wchar_t, but there is no way for us to know the * internal encoding of wchar_t. Moreover, it is nearly * impossible to convert UCS-4 into wchar_t (except for iconv, * which is way too much overhead). * Therefore, we use our own copy of wcwidth(). Lets just hope * that glibc will one day export it's internal UCS-4 and UTF-8 * helpers for direct use. */ assert_cc(sizeof(wchar_t) >= 4); r = mk_wcwidth((wchar_t)str[i]); if (r > 0 && (unsigned int)r > max) max = r; } return max; } /** * term_cell_init() - Initialize a new cell * @cell: cell to initialize * @ch: character to set on the cell or TERM_CHAR_NULL * @cwidth: character width of @ch * @attr: attributes to set on the cell or NULL * @age: age to set on the cell or TERM_AGE_NULL * * This initializes a new cell. The backing-memory of the cell must be allocated * by the caller beforehand. The caller is responsible to destroy the cell via * term_cell_destroy() before freeing the backing-memory. * * It is safe (and supported!) to use: * zero(*c); * instead of: * term_cell_init(c, TERM_CHAR_NULL, NULL, TERM_AGE_NULL); * * Note that this call takes ownership of @ch. If you want to use it yourself * after this call, you need to duplicate it before calling this. */ static void term_cell_init(term_cell *cell, term_char_t ch, unsigned int cwidth, const term_attr *attr, term_age_t age) { assert(cell); cell->ch = ch; cell->cwidth = cwidth; cell->age = age; if (attr) memcpy(&cell->attr, attr, sizeof(*attr)); else zero(cell->attr); } /** * term_cell_destroy() - Destroy previously initialized cell * @cell: cell to destroy or NULL * * This releases all resources associated with a cell. The backing memory is * kept as-is. It's the responsibility of the caller to manage it. * * You must not call any other cell operations on this cell after this call * returns. You must re-initialize the cell via term_cell_init() before you can * use it again. * * If @cell is NULL, this is a no-op. */ static void term_cell_destroy(term_cell *cell) { if (!cell) return; term_char_free(cell->ch); } /** * term_cell_set() - Change contents of a cell * @cell: cell to modify * @ch: character to set on the cell or cell->ch * @cwidth: character width of @ch or cell->cwidth * @attr: attributes to set on the cell or NULL * @age: age to set on the cell or cell->age * * This changes the contents of a cell. It can be used to change the character, * attributes and age. To keep the current character, pass cell->ch as @ch. To * reset the current attributes, pass NULL. To keep the current age, pass * cell->age. * * This call takes ownership of @ch. You need to duplicate it first, in case you * want to use it for your own purposes after this call. * * The cell must have been initialized properly before calling this. See * term_cell_init(). */ static void term_cell_set(term_cell *cell, term_char_t ch, unsigned int cwidth, const term_attr *attr, term_age_t age) { assert(cell); if (!term_char_same(ch, cell->ch)) { term_char_free(cell->ch); cell->ch = ch; } cell->cwidth = cwidth; cell->age = age; if (attr) memcpy(&cell->attr, attr, sizeof(*attr)); else zero(cell->attr); } /** * term_cell_append() - Append a combining-char to a cell * @cell: cell to modify * @ucs4: UCS-4 character to append to the cell * @age: new age to set on the cell or cell->age * * This appends a combining-character to a cell. No validation of the UCS-4 * character is done, so this can be used to append any character. Additionally, * this can update the age of the cell. * * The cell must have been initialized properly before calling this. See * term_cell_init(). */ static void term_cell_append(term_cell *cell, uint32_t ucs4, term_age_t age) { assert(cell); cell->ch = term_char_merge(cell->ch, ucs4); cell->age = age; } /** * term_cell_init_n() - Initialize an array of cells * @cells: pointer to an array of cells to initialize * @n: number of cells * @attr: attributes to set on all cells or NULL * @age: age to set on all cells * * This is the same as term_cell_init() but initializes an array of cells. * Furthermore, this always sets the character to TERM_CHAR_NULL. * If you want to set a specific characters on all cells, you need to hard-code * this loop and duplicate the character for each cell. */ static void term_cell_init_n(term_cell *cells, unsigned int n, const term_attr *attr, term_age_t age) { for ( ; n > 0; --n, ++cells) term_cell_init(cells, TERM_CHAR_NULL, 0, attr, age); } /** * term_cell_destroy_n() - Destroy an array of cells * @cells: pointer to an array of cells to destroy * @n: number of cells * * This is the same as term_cell_destroy() but destroys an array of cells. */ static void term_cell_destroy_n(term_cell *cells, unsigned int n) { for ( ; n > 0; --n, ++cells) term_cell_destroy(cells); } /** * term_cell_clear_n() - Clear contents of an array of cells * @cells: pointer to an array of cells to modify * @n: number of cells * @attr: attributes to set on all cells or NULL * @age: age to set on all cells * * This is the same as term_cell_set() but operates on an array of cells. Note * that all characters are always set to TERM_CHAR_NULL, unlike term_cell_set() * which takes the character as argument. * If you want to set a specific characters on all cells, you need to hard-code * this loop and duplicate the character for each cell. */ static void term_cell_clear_n(term_cell *cells, unsigned int n, const term_attr *attr, term_age_t age) { for ( ; n > 0; --n, ++cells) term_cell_set(cells, TERM_CHAR_NULL, 0, attr, age); } /** * term_line_new() - Allocate a new line * @out: place to store pointer to new line * * This allocates and initialized a new line. The line is unlinked and * independent of any page. It can be used for any purpose. The initial * cell-count is set to 0. * * The line has to be freed via term_line_free() once it's no longer needed. * * Returns: 0 on success, negative error code on failure. */ int term_line_new(term_line **out) { _term_line_free_ term_line *line = NULL; assert_return(out, -EINVAL); line = new0(term_line, 1); if (!line) return -ENOMEM; *out = line; line = NULL; return 0; } /** * term_line_free() - Free a line * @line: line to free or NULL * * This frees a line that was previously allocated via term_line_free(). All its * cells are released, too. * * If @line is NULL, this is a no-op. */ term_line *term_line_free(term_line *line) { if (!line) return NULL; term_cell_destroy_n(line->cells, line->n_cells); free(line->cells); free(line); return NULL; } /** * term_line_reserve() - Pre-allocate cells for a line * @line: line to pre-allocate cells for * @width: numbers of cells the line shall have pre-allocated * @attr: attribute for all allocated cells or NULL * @age: current age for all modifications * @protect_width: width to protect from erasure * * This pre-allocates cells for this line. Please note that @width is the number * of cells the line is guaranteed to have allocated after this call returns. * It's not the number of cells that are added, neither is it the new width of * the line. * * This function never frees memory. That is, reducing the line-width will * always succeed, same is true for increasing the width to a previously set * width. * * @attr and @age are used to initialize new cells. Additionally, any * existing cell outside of the protected area specified by @protect_width are * cleared and reset with @attr and @age. * * Returns: 0 on success, negative error code on failure. */ int term_line_reserve(term_line *line, unsigned int width, const term_attr *attr, term_age_t age, unsigned int protect_width) { unsigned int min_width; term_cell *t; assert_return(line, -EINVAL); /* reset existing cells if required */ min_width = MIN(line->n_cells, width); if (min_width > protect_width) term_cell_clear_n(line->cells + protect_width, min_width - protect_width, attr, age); /* allocate new cells if required */ if (width > line->n_cells) { t = realloc_multiply(line->cells, sizeof(*t), width); if (!t) return -ENOMEM; if (!attr && !age) memzero(t + line->n_cells, sizeof(*t) * (width - line->n_cells)); else term_cell_init_n(t + line->n_cells, width - line->n_cells, attr, age); line->cells = t; line->n_cells = width; } line->fill = MIN(line->fill, protect_width); return 0; } /** * term_line_set_width() - Change width of a line * @line: line to modify * @width: new width * * This changes the actual width of a line. It is the caller's responsibility * to use term_line_reserve() to make sure enough space is allocated. If @width * is greater than the allocated size, it is cropped. * * This does not modify any cells. Use term_line_reserve() or term_line_erase() * to clear any newly added cells. * * NOTE: The fill state is cropped at line->width. Therefore, if you increase * the line-width afterwards, but there is a multi-cell character at the * end of the line that got cropped, then the fill-state will _not_ be * adjusted. * This means, the fill-state always includes the cells up to the start * of the right-most character, but it might or might not cover it until * its end. This should be totally fine, though. You should never access * multi-cell tails directly, anyway. */ void term_line_set_width(term_line *line, unsigned int width) { assert(line); if (width > line->n_cells) width = line->n_cells; line->width = width; line->fill = MIN(line->fill, width); } /** * line_insert() - Insert characters and move existing cells to the right * @from: position to insert cells at * @num: number of cells to insert * @head_char: character that is set on the first cell * @head_cwidth: character-length of @head_char * @attr: attribute for all inserted cells or NULL * @age: current age for all modifications * * The INSERT operation (or writes with INSERT_MODE) writes data at a specific * position on a line and shifts the existing cells to the right. Cells that are * moved beyond the right hand border are discarded. * * This helper contains the actual INSERT implementation which is independent of * the data written. It works on cells, not on characters. The first cell is set * to @head_char, all others are reset to TERM_CHAR_NULL. See each caller for a * more detailed description. */ static inline void line_insert(term_line *line, unsigned int from, unsigned int num, term_char_t head_char, unsigned int head_cwidth, const term_attr *attr, term_age_t age) { unsigned int i, rem, move; if (from >= line->width) return; if (from + num < from || from + num > line->width) num = line->width - from; if (!num) return; move = line->width - from - num; rem = MIN(num, move); if (rem > 0) { /* * Make room for @num cells; shift cells to the right if * required. @rem is the number of remaining cells that we will * knock off on the right and overwrite during the right shift. * * For INSERT_MODE, @num/@rem are usually 1 or 2, @move is 50% * of the line on average. Therefore, the actual move is quite * heavy and we can safely invalidate cells manually instead of * the whole line. * However, for INSERT operations, any parameters are * possible. But we cannot place any assumption on its usage * across applications, so we just handle it the same as * INSERT_MODE and do per-cell invalidation. */ /* destroy cells that are knocked off on the right */ term_cell_destroy_n(line->cells + line->width - rem, rem); /* move remaining bulk of cells */ memmove(line->cells + from + num, line->cells + from, sizeof(*line->cells) * move); /* invalidate cells */ for (i = 0; i < move; ++i) line->cells[from + num + i].age = age; /* initialize fresh head-cell */ term_cell_init(line->cells + from, head_char, head_cwidth, attr, age); /* initialize fresh tail-cells */ term_cell_init_n(line->cells + from + 1, num - 1, attr, age); /* adjust fill-state */ DISABLE_WARNING_SHADOW; line->fill = MIN(line->width, MAX(line->fill + num, from + num)); REENABLE_WARNING; } else { /* modify head-cell */ term_cell_set(line->cells + from, head_char, head_cwidth, attr, age); /* reset tail-cells */ term_cell_clear_n(line->cells + from + 1, num - 1, attr, age); /* adjust fill-state */ line->fill = line->width; } } /** * term_line_write() - Write to a single, specific cell * @line: line to write to * @pos_x: x-position of cell in @line to write to * @ch: character to write to the cell * @cwidth: character width of @ch * @attr: attributes to set on the cell or NULL * @age: current age for all modifications * @insert_mode: true if INSERT-MODE is enabled * * This writes to a specific cell in a line. The cell is addressed by its * X-position @pos_x. If that cell does not exist, this is a no-op. * * @ch and @attr are set on this cell. * * If @insert_mode is true, this inserts the character instead of overwriting * existing data (existing data is now moved to the right before writing). * * This function is the low-level handler of normal writes to a terminal. */ void term_line_write(term_line *line, unsigned int pos_x, term_char_t ch, unsigned int cwidth, const term_attr *attr, term_age_t age, bool insert_mode) { unsigned int len; assert(line); if (pos_x >= line->width) return; len = MAX(1U, cwidth); if (pos_x + len < pos_x || pos_x + len > line->width) len = line->width - pos_x; if (!len) return; if (insert_mode) { /* Use line_insert() to insert the character-head and fill * the remains with NULLs. */ line_insert(line, pos_x, len, ch, cwidth, attr, age); } else { /* modify head-cell */ term_cell_set(line->cells + pos_x, ch, cwidth, attr, age); /* reset tail-cells */ term_cell_clear_n(line->cells + pos_x + 1, len - 1, attr, age); /* adjust fill-state */ DISABLE_WARNING_SHADOW; line->fill = MIN(line->width, MAX(line->fill, pos_x + len)); REENABLE_WARNING; } } /** * term_line_insert() - Insert empty cells * @line: line to insert empty cells into * @from: x-position where to insert cells * @num: number of cells to insert * @attr: attributes to set on the cells or NULL * @age: current age for all modifications * * This inserts @num empty cells at position @from in line @line. All existing * cells to the right are shifted to make room for the new cells. Cells that get * pushed beyond the right hand border are discarded. */ void term_line_insert(term_line *line, unsigned int from, unsigned int num, const term_attr *attr, term_age_t age) { /* use line_insert() to insert @num empty cells */ return line_insert(line, from, num, TERM_CHAR_NULL, 0, attr, age); } /** * term_line_delete() - Delete cells from line * @line: line to delete cells from * @from: position to delete cells at * @num: number of cells to delete * @attr: attributes to set on any new cells * @age: current age for all modifications * * Delete cells from a line. All cells to the right of the deleted cells are * shifted to the left to fill the empty space. New cells appearing on the right * hand border are cleared and initialized with @attr. */ void term_line_delete(term_line *line, unsigned int from, unsigned int num, const term_attr *attr, term_age_t age) { unsigned int rem, move, i; assert(line); if (from >= line->width) return; if (from + num < from || from + num > line->width) num = line->width - from; if (!num) return; /* destroy and move as many upfront as possible */ move = line->width - from - num; rem = MIN(num, move); if (rem > 0) { /* destroy to be removed cells */ term_cell_destroy_n(line->cells + from, rem); /* move tail upfront */ memmove(line->cells + from, line->cells + from + num, sizeof(*line->cells) * move); /* invalidate copied cells */ for (i = 0; i < move; ++i) line->cells[from + i].age = age; /* initialize tail that was moved away */ term_cell_init_n(line->cells + line->width - rem, rem, attr, age); /* reset remaining cells in case the move was too small */ if (num > move) term_cell_clear_n(line->cells + from + move, num - move, attr, age); } else { /* reset cells */ term_cell_clear_n(line->cells + from, num, attr, age); } /* adjust fill-state */ if (from + num < line->fill) line->fill -= num; else if (from < line->fill) line->fill = from; } /** * term_line_append_combchar() - Append combining char to existing cell * @line: line to modify * @pos_x: position of cell to append combining char to * @ucs4: combining character to append * @age: current age for all modifications * * Unicode allows trailing combining characters, which belong to the * char in front of them. The caller is responsible of detecting * combining characters and calling term_line_append_combchar() instead of * term_line_write(). This simply appends the char to the correct cell then. * If the cell is not in the visible area, this call is skipped. * * Note that control-sequences are not 100% compatible with combining * characters as they require delayed parsing. However, we must handle * control-sequences immediately. Therefore, there might be trailing * combining chars that should be discarded by the parser. * However, to prevent programming errors, we're also being pedantic * here and discard weirdly placed combining chars. This prevents * situations were invalid content is parsed into the terminal and you * might end up with cells containing only combining chars. * * Long story short: To get combining-characters working with old-fashioned * terminal-emulation, we parse them exclusively for direct cell-writes. Other * combining-characters are usually simply discarded and ignored. */ void term_line_append_combchar(term_line *line, unsigned int pos_x, uint32_t ucs4, term_age_t age) { assert(line); if (pos_x >= line->width) return; /* Unused cell? Skip appending any combining chars then. */ if (term_char_is_null(line->cells[pos_x].ch)) return; term_cell_append(line->cells + pos_x, ucs4, age); } /** * term_line_erase() - Erase parts of a line * @line: line to modify * @from: position to start the erase * @num: number of cells to erase * @attr: attributes to initialize erased cells with * @age: current age for all modifications * @keep_protected: true if protected cells should be kept * * This is the standard erase operation. It clears all cells in the targeted * area and re-initializes them. Cells to the right are not shifted left, you * must use DELETE to achieve that. Cells outside the visible area are skipped. * * If @keep_protected is true, protected cells will not be erased. */ void term_line_erase(term_line *line, unsigned int from, unsigned int num, const term_attr *attr, term_age_t age, bool keep_protected) { term_cell *cell; unsigned int i, last_protected; assert(line); if (from >= line->width) return; if (from + num < from || from + num > line->width) num = line->width - from; if (!num) return; last_protected = 0; for (i = 0; i < num; ++i) { cell = line->cells + from + i; if (keep_protected && cell->attr.protect) { /* only count protected-cells inside the fill-region */ if (from + i < line->fill) last_protected = from + i; continue; } term_cell_set(cell, TERM_CHAR_NULL, 0, attr, age); } /* Adjust fill-state. This is a bit tricks, we can only adjust it in * case the erase-region starts inside the fill-region and ends at the * tail or beyond the fill-region. Otherwise, the current fill-state * stays as it was. * Furthermore, we must account for protected cells. The loop above * ensures that protected-cells are only accounted for if they're * inside the fill-region. */ if (from < line->fill && from + num >= line->fill) line->fill = MAX(from, last_protected); } /** * term_line_reset() - Reset a line * @line: line to reset * @attr: attributes to initialize all cells with * @age: current age for all modifications * * This resets all visible cells of a line and sets their attributes and ages * to @attr and @age. This is equivalent to erasing a whole line via * term_line_erase(). */ void term_line_reset(term_line *line, const term_attr *attr, term_age_t age) { assert(line); return term_line_erase(line, 0, line->width, attr, age, 0); } /** * term_line_link() - Link line in front of a list * @line: line to link * @first: member pointing to first entry * @last: member pointing to last entry * * This links a line into a list of lines. The line is inserted at the front and * must not be linked, yet. See the TERM_LINE_LINK() macro for an easier usage of * this. */ void term_line_link(term_line *line, term_line **first, term_line **last) { assert(line); assert(first); assert(last); assert(!line->lines_prev); assert(!line->lines_next); line->lines_prev = NULL; line->lines_next = *first; if (*first) (*first)->lines_prev = line; else *last = line; *first = line; } /** * term_line_link_tail() - Link line at tail of a list * @line: line to link * @first: member pointing to first entry * @last: member pointing to last entry * * Same as term_line_link() but links the line at the tail. */ void term_line_link_tail(term_line *line, term_line **first, term_line **last) { assert(line); assert(first); assert(last); assert(!line->lines_prev); assert(!line->lines_next); line->lines_next = NULL; line->lines_prev = *last; if (*last) (*last)->lines_next = line; else *first = line; *last = line; } /** * term_line_unlink() - Unlink line from a list * @line: line to unlink * @first: member pointing to first entry * @last: member pointing to last entry * * This unlinks a previously linked line. See TERM_LINE_UNLINK() for an easier to * use macro. */ void term_line_unlink(term_line *line, term_line **first, term_line **last) { assert(line); assert(first); assert(last); if (line->lines_prev) line->lines_prev->lines_next = line->lines_next; else *first = line->lines_next; if (line->lines_next) line->lines_next->lines_prev = line->lines_prev; else *last = line->lines_prev; line->lines_prev = NULL; line->lines_next = NULL; } /** * term_page_new() - Allocate new page * @out: storage for pointer to new page * * Allocate a new page. The initial dimensions are 0/0. * * Returns: 0 on success, negative error code on failure. */ int term_page_new(term_page **out) { _term_page_free_ term_page *page = NULL; assert_return(out, -EINVAL); page = new0(term_page, 1); if (!page) return -ENOMEM; *out = page; page = NULL; return 0; } /** * term_page_free() - Free page * @page: page to free or NULL * * Free a previously allocated page and all associated data. If @page is NULL, * this is a no-op. * * Returns: NULL */ term_page *term_page_free(term_page *page) { unsigned int i; if (!page) return NULL; for (i = 0; i < page->n_lines; ++i) term_line_free(page->lines[i]); free(page->line_cache); free(page->lines); free(page); return NULL; } /** * term_page_get_cell() - Return pointer to requested cell * @page: page to operate on * @x: x-position of cell * @y: y-position of cell * * This returns a pointer to the cell at position @x/@y. You're free to modify * this cell as much as you like. However, once you call any other function on * the page, you must drop the pointer to the cell. * * Returns: Pointer to the cell or NULL if out of the visible area. */ term_cell *term_page_get_cell(term_page *page, unsigned int x, unsigned int y) { assert_return(page, NULL); if (x >= page->width) return NULL; if (y >= page->height) return NULL; return &page->lines[y]->cells[x]; } /** * page_scroll_up() - Scroll up * @page: page to operate on * @new_width: width to use for any new line moved into the visible area * @num: number of lines to scroll up * @attr: attributes to set on new lines * @age: age to use for all modifications * @history: history to use for old lines or NULL * * This scrolls the scroll-region by @num lines. New lines are cleared and reset * with the given attributes. Old lines are moved into the history if non-NULL. * If a new line is allocated, moved from the history buffer or moved from * outside the visible region into the visible region, this call makes sure it * has at least @width cells allocated. If a possible memory-allocation fails, * the previous line is reused. This has the side effect, that it will not be * linked into the history buffer. * * If the scroll-region is empty, this is a no-op. */ static void page_scroll_up(term_page *page, unsigned int new_width, unsigned int num, const term_attr *attr, term_age_t age, term_history *history) { term_line *line, **cache; unsigned int i; int r; assert(page); if (num > page->scroll_num) num = page->scroll_num; if (num < 1) return; /* Better safe than sorry: avoid under-allocating lines, even when * resizing. */ new_width = MAX(new_width, page->width); cache = page->line_cache; /* Try moving lines into history and allocate new lines for each moved * line. In case allocation fails, or if we have no history, reuse the * line. * We keep the lines in the line-cache so we can safely move the * remaining lines around. */ for (i = 0; i < num; ++i) { line = page->lines[page->scroll_idx + i]; r = -EAGAIN; if (history) { r = term_line_new(&cache[i]); if (r >= 0) { r = term_line_reserve(cache[i], new_width, attr, age, 0); if (r < 0) term_line_free(cache[i]); else term_line_set_width(cache[i], page->width); } } if (r >= 0) { term_history_push(history, line); } else { cache[i] = line; term_line_reset(line, attr, age); } } if (num < page->scroll_num) { memmove(page->lines + page->scroll_idx, page->lines + page->scroll_idx + num, sizeof(*page->lines) * (page->scroll_num - num)); /* update age of moved lines */ for (i = 0; i < page->scroll_num - num; ++i) page->lines[page->scroll_idx + i]->age = age; } /* copy remaining lines from cache; age is already updated */ memcpy(page->lines + page->scroll_idx + page->scroll_num - num, cache, sizeof(*cache) * num); /* update fill */ page->scroll_fill -= MIN(page->scroll_fill, num); } /** * page_scroll_down() - Scroll down * @page: page to operate on * @new_width: width to use for any new line moved into the visible area * @num: number of lines to scroll down * @attr: attributes to set on new lines * @age: age to use for all modifications * @history: history to use for new lines or NULL * * This scrolls the scroll-region by @num lines. New lines are retrieved from * the history or cleared if the history is empty or NULL. * * Usually, scroll-down implies that new lines are cleared. Therefore, you're * highly encouraged to set @history to NULL. However, if you resize a terminal, * you might want to include history-lines in the new area. In that case, you * should set @history to non-NULL. * * If a new line is allocated, moved from the history buffer or moved from * outside the visible region into the visible region, this call makes sure it * has at least @width cells allocated. If a possible memory-allocation fails, * the previous line is reused. This will have the side-effect that lines from * the history will not get visible on-screen but kept in history. * * If the scroll-region is empty, this is a no-op. */ static void page_scroll_down(term_page *page, unsigned int new_width, unsigned int num, const term_attr *attr, term_age_t age, term_history *history) { term_line *line, **cache, *t; unsigned int i, last_idx; assert(page); if (num > page->scroll_num) num = page->scroll_num; if (num < 1) return; /* Better safe than sorry: avoid under-allocating lines, even when * resizing. */ new_width = MAX(new_width, page->width); cache = page->line_cache; last_idx = page->scroll_idx + page->scroll_num - 1; /* Try pulling out lines from history; if history is empty or if no * history is given, we reuse the to-be-removed lines. Otherwise, those * lines are released. */ for (i = 0; i < num; ++i) { line = page->lines[last_idx - i]; t = NULL; if (history) t = term_history_pop(history, new_width, attr, age); if (t) { cache[num - 1 - i] = t; term_line_free(line); } else { cache[num - 1 - i] = line; term_line_reset(line, attr, age); } } if (num < page->scroll_num) { memmove(page->lines + page->scroll_idx + num, page->lines + page->scroll_idx, sizeof(*page->lines) * (page->scroll_num - num)); /* update age of moved lines */ for (i = 0; i < page->scroll_num - num; ++i) page->lines[page->scroll_idx + num + i]->age = age; } /* copy remaining lines from cache; age is already updated */ memcpy(page->lines + page->scroll_idx, cache, sizeof(*cache) * num); /* update fill; but only if there's already content in it */ if (page->scroll_fill > 0) page->scroll_fill = MIN(page->scroll_num, page->scroll_fill + num); } /** * page_reserve() - Reserve page area * @page: page to modify * @cols: required columns (width) * @rows: required rows (height) * @attr: attributes for newly allocated cells * @age: age to set on any modified cells * * This allocates the required amount of lines and cells to guarantee that the * page has at least the demanded dimensions of @cols x @rows. Note that this * never shrinks the page-memory. We keep cells allocated for performance * reasons. * * Additionally to allocating lines, this also clears any newly added cells so * you can safely change the size afterwards without clearing new cells. * * Note that you must be careful what operations you call on the page between * page_reserve() and updating page->width/height. Any newly allocated line (or * shifted line) might not meet your new width/height expectations. * * Returns: 0 on success, negative error code on failure. */ int term_page_reserve(term_page *page, unsigned int cols, unsigned int rows, const term_attr *attr, term_age_t age) { _term_line_free_ term_line *line = NULL; unsigned int i, min_lines; term_line **t; int r; assert_return(page, -EINVAL); /* * First make sure the first MIN(page->n_lines, rows) lines have at * least the required width of @cols. This does not modify any visible * cells in the existing @page->width x @page->height area, therefore, * we can safely bail out afterwards in case anything else fails. * Note that lines in between page->height and page->n_lines might be * shorter than page->width. Hence, we need to resize them all, but we * can skip some of them for better performance. */ min_lines = MIN(page->n_lines, rows); for (i = 0; i < min_lines; ++i) { /* lines below page->height have at least page->width cells */ if (cols < page->width && i < page->height) continue; r = term_line_reserve(page->lines[i], cols, attr, age, (i < page->height) ? page->width : 0); if (r < 0) return r; } /* * We now know the first @min_lines lines have at least width @cols and * are prepared for resizing. We now only have to allocate any * additional lines below @min_lines in case @rows is greater than * page->n_lines. */ if (rows > page->n_lines) { t = realloc_multiply(page->lines, sizeof(*t), rows); if (!t) return -ENOMEM; page->lines = t; t = realloc_multiply(page->line_cache, sizeof(*t), rows); if (!t) return -ENOMEM; page->line_cache = t; while (page->n_lines < rows) { r = term_line_new(&line); if (r < 0) return r; r = term_line_reserve(line, cols, attr, age, 0); if (r < 0) return r; page->lines[page->n_lines++] = line; line = NULL; } } return 0; } /** * term_page_resize() - Resize page * @page: page to modify * @cols: number of columns (width) * @rows: number of rows (height) * @attr: attributes for newly allocated cells * @age: age to set on any modified cells * @history: history buffer to use for new/old lines or NULL * * This changes the visible dimensions of a page. You must have called * term_page_reserve() beforehand, otherwise, this will fail. * * Returns: 0 on success, negative error code on failure. */ void term_page_resize(term_page *page, unsigned int cols, unsigned int rows, const term_attr *attr, term_age_t age, term_history *history) { unsigned int i, num, empty, max, old_height; term_line *line; assert(page); assert(page->n_lines >= rows); old_height = page->height; if (rows < old_height) { /* * If we decrease the terminal-height, we emulate a scroll-up. * This way, existing data from the scroll-area is moved into * the history, making space at the bottom to reduce the screen * height. In case the scroll-fill indicates empty lines, we * reduce the amount of scrolled lines. * Once scrolled, we have to move the lower margin from below * the scroll area up so it is preserved. */ /* move lines to history if scroll region is filled */ num = old_height - rows; empty = page->scroll_num - page->scroll_fill; if (num > empty) page_scroll_up(page, cols, num - empty, attr, age, history); /* move lower margin up; drop its lines if not enough space */ num = LESS_BY(old_height, page->scroll_idx + page->scroll_num); max = LESS_BY(rows, page->scroll_idx); num = MIN(num, max); if (num > 0) { unsigned int top, bottom; top = rows - num; bottom = page->scroll_idx + page->scroll_num; /* might overlap; must run topdown, not bottomup */ for (i = 0; i < num; ++i) { line = page->lines[top + i]; page->lines[top + i] = page->lines[bottom + i]; page->lines[bottom + i] = line; } } /* update vertical extents */ page->height = rows; page->scroll_idx = MIN(page->scroll_idx, rows); page->scroll_num -= MIN(page->scroll_num, old_height - rows); /* fill is already up-to-date or 0 due to scroll-up */ } else if (rows > old_height) { /* * If we increase the terminal-height, we emulate a scroll-down * and fetch new lines from the history. * New lines are always accounted to the scroll-region. Thus we * have to preserve the lower margin first, by moving it down. */ /* move lower margin down */ num = LESS_BY(old_height, page->scroll_idx + page->scroll_num); if (num > 0) { unsigned int top, bottom; top = page->scroll_idx + page->scroll_num; bottom = top + (rows - old_height); /* might overlap; must run bottomup, not topdown */ for (i = num; i-- > 0; ) { line = page->lines[top + i]; page->lines[top + i] = page->lines[bottom + i]; page->lines[bottom + i] = line; } } /* update vertical extents */ page->height = rows; page->scroll_num = MIN(LESS_BY(rows, page->scroll_idx), page->scroll_num + (rows - old_height)); /* check how many lines can be received from history */ if (history) num = term_history_peek(history, rows - old_height, cols, attr, age); else num = 0; /* retrieve new lines from history if available */ if (num > 0) page_scroll_down(page, cols, num, attr, age, history); } /* set horizontal extents */ page->width = cols; for (i = 0; i < page->height; ++i) term_line_set_width(page->lines[i], cols); } /** * term_page_write() - Write to a single cell * @page: page to operate on * @pos_x: x-position of cell to write to * @pos_y: y-position of cell to write to * @ch: character to write * @cwidth: character-width of @ch * @attr: attributes to set on the cell or NULL * @age: age to use for all modifications * @insert_mode: true if INSERT-MODE is enabled * * This writes a character to a specific cell. If the cell is beyond bounds, * this is a no-op. @attr and @age are used to update the cell. @flags can be * used to alter the behavior of this function. * * This is a wrapper around term_line_write(). * * This call does not wrap around lines. That is, this only operates on a single * line. */ void term_page_write(term_page *page, unsigned int pos_x, unsigned int pos_y, term_char_t ch, unsigned int cwidth, const term_attr *attr, term_age_t age, bool insert_mode) { assert(page); if (pos_y >= page->height) return; term_line_write(page->lines[pos_y], pos_x, ch, cwidth, attr, age, insert_mode); } /** * term_page_insert_cells() - Insert cells into a line * @page: page to operate on * @from_x: x-position where to insert new cells * @from_y: y-position where to insert new cells * @num: number of cells to insert * @attr: attributes to set on new cells or NULL * @age: age to use for all modifications * * This inserts new cells into a given line. This is a wrapper around * term_line_insert(). * * This call does not wrap around lines. That is, this only operates on a single * line. */ void term_page_insert_cells(term_page *page, unsigned int from_x, unsigned int from_y, unsigned int num, const term_attr *attr, term_age_t age) { assert(page); if (from_y >= page->height) return; term_line_insert(page->lines[from_y], from_x, num, attr, age); } /** * term_page_delete_cells() - Delete cells from a line * @page: page to operate on * @from_x: x-position where to delete cells * @from_y: y-position where to delete cells * @num: number of cells to delete * @attr: attributes to set on new cells or NULL * @age: age to use for all modifications * * This deletes cells from a given line. This is a wrapper around * term_line_delete(). * * This call does not wrap around lines. That is, this only operates on a single * line. */ void term_page_delete_cells(term_page *page, unsigned int from_x, unsigned int from_y, unsigned int num, const term_attr *attr, term_age_t age) { assert(page); if (from_y >= page->height) return; term_line_delete(page->lines[from_y], from_x, num, attr, age); } /** * term_page_append_combchar() - Append combining-character to a cell * @page: page to operate on * @pos_x: x-position of target cell * @pos_y: y-position of target cell * @ucs4: combining character to append * @age: age to use for all modifications * * This appends a combining-character to a specific cell. This is a wrapper * around term_line_append_combchar(). */ void term_page_append_combchar(term_page *page, unsigned int pos_x, unsigned int pos_y, uint32_t ucs4, term_age_t age) { assert(page); if (pos_y >= page->height) return; term_line_append_combchar(page->lines[pos_y], pos_x, ucs4, age); } /** * term_page_erase() - Erase parts of a page * @page: page to operate on * @from_x: x-position where to start erasure (inclusive) * @from_y: y-position where to start erasure (inclusive) * @to_x: x-position where to stop erasure (inclusive) * @to_y: y-position where to stop erasure (inclusive) * @attr: attributes to set on cells * @age: age to use for all modifications * @keep_protected: true if protected cells should be kept * * This erases all cells starting at @from_x/@from_y up to @to_x/@to_y. Note * that this wraps around line-boundaries so lines between @from_y and @to_y * are cleared entirely. * * Lines outside the visible area are left untouched. */ void term_page_erase(term_page *page, unsigned int from_x, unsigned int from_y, unsigned int to_x, unsigned int to_y, const term_attr *attr, term_age_t age, bool keep_protected) { unsigned int i, from, to; assert(page); for (i = from_y; i <= to_y && i < page->height; ++i) { from = 0; to = page->width; if (i == from_y) from = from_x; if (i == to_y) to = to_x; term_line_erase(page->lines[i], from, LESS_BY(to, from), attr, age, keep_protected); } } /** * term_page_reset() - Reset page * @page: page to modify * @attr: attributes to set on cells * @age: age to use for all modifications * * This erases the whole visible page. See term_page_erase(). */ void term_page_reset(term_page *page, const term_attr *attr, term_age_t age) { assert(page); return term_page_erase(page, 0, 0, page->width - 1, page->height - 1, attr, age, 0); } /** * term_page_set_scroll_region() - Set scroll region * @page: page to operate on * @idx: start-index of scroll region * @num: number of lines in scroll region * * This sets the scroll region of a page. Whenever an operation needs to scroll * lines, it scrolls them inside of that region. Lines outside the region are * left untouched. In case a scroll-operation is targeted outside of this * region, it will implicitly get a scroll-region of only one line (i.e., no * scroll region at all). * * Note that the scroll-region is clipped to the current page-extents. Growing * or shrinking the page always accounts new/old lines to the scroll region and * moves top/bottom margins accordingly so they're preserved. */ void term_page_set_scroll_region(term_page *page, unsigned int idx, unsigned int num) { assert(page); if (page->height < 1) { page->scroll_idx = 0; page->scroll_num = 0; } else { page->scroll_idx = MIN(idx, page->height - 1); page->scroll_num = MIN(num, page->height - page->scroll_idx); } } /** * term_page_scroll_up() - Scroll up * @page: page to operate on * @num: number of lines to scroll up * @attr: attributes to set on new lines * @age: age to use for all modifications * @history: history to use for old lines or NULL * * This scrolls the scroll-region by @num lines. New lines are cleared and reset * with the given attributes. Old lines are moved into the history if non-NULL. * * If the scroll-region is empty, this is a no-op. */ void term_page_scroll_up(term_page *page, unsigned int num, const term_attr *attr, term_age_t age, term_history *history) { page_scroll_up(page, page->width, num, attr, age, history); } /** * term_page_scroll_down() - Scroll down * @page: page to operate on * @num: number of lines to scroll down * @attr: attributes to set on new lines * @age: age to use for all modifications * @history: history to use for new lines or NULL * * This scrolls the scroll-region by @num lines. New lines are retrieved from * the history or cleared if the history is empty or NULL. * * Usually, scroll-down implies that new lines are cleared. Therefore, you're * highly encouraged to set @history to NULL. However, if you resize a terminal, * you might want to include history-lines in the new area. In that case, you * should set @history to non-NULL. * * If the scroll-region is empty, this is a no-op. */ void term_page_scroll_down(term_page *page, unsigned int num, const term_attr *attr, term_age_t age, term_history *history) { page_scroll_down(page, page->width, num, attr, age, history); } /** * term_page_insert_lines() - Insert new lines * @page: page to operate on * @pos_y: y-position where to insert new lines * @num: number of lines to insert * @attr: attributes to set on new lines * @age: age to use for all modifications * * This inserts @num new lines at position @pos_y. If @pos_y is beyond * boundaries or @num is 0, this is a no-op. * All lines below @pos_y are moved down to make space for the new lines. Lines * on the bottom are dropped. Note that this only moves lines above or inside * the scroll-region. If @pos_y is below the scroll-region, a scroll-region of * one line is implied (which means the line is simply cleared). */ void term_page_insert_lines(term_page *page, unsigned int pos_y, unsigned int num, const term_attr *attr, term_age_t age) { unsigned int scroll_idx, scroll_num; assert(page); if (pos_y >= page->height) return; if (num >= page->height) num = page->height; /* remember scroll-region */ scroll_idx = page->scroll_idx; scroll_num = page->scroll_num; /* set scroll-region temporarily so we can reuse scroll_down() */ { page->scroll_idx = pos_y; if (pos_y >= scroll_idx + scroll_num) page->scroll_num = 1; else if (pos_y >= scroll_idx) page->scroll_num -= pos_y - scroll_idx; else page->scroll_num += scroll_idx - pos_y; term_page_scroll_down(page, num, attr, age, NULL); } /* reset scroll-region */ page->scroll_idx = scroll_idx; page->scroll_num = scroll_num; } /** * term_page_delete_lines() - Delete lines * @page: page to operate on * @pos_y: y-position where to delete lines * @num: number of lines to delete * @attr: attributes to set on new lines * @age: age to use for all modifications * * This deletes @num lines at position @pos_y. If @pos_y is beyond boundaries or * @num is 0, this is a no-op. * All lines below @pos_y are moved up into the newly made space. New lines * on the bottom are clear. Note that this only moves lines above or inside * the scroll-region. If @pos_y is below the scroll-region, a scroll-region of * one line is implied (which means the line is simply cleared). */ void term_page_delete_lines(term_page *page, unsigned int pos_y, unsigned int num, const term_attr *attr, term_age_t age) { unsigned int scroll_idx, scroll_num; assert(page); if (pos_y >= page->height) return; if (num >= page->height) num = page->height; /* remember scroll-region */ scroll_idx = page->scroll_idx; scroll_num = page->scroll_num; /* set scroll-region temporarily so we can reuse scroll_up() */ { page->scroll_idx = pos_y; if (pos_y >= scroll_idx + scroll_num) page->scroll_num = 1; else if (pos_y > scroll_idx) page->scroll_num -= pos_y - scroll_idx; else page->scroll_num += scroll_idx - pos_y; term_page_scroll_up(page, num, attr, age, NULL); } /* reset scroll-region */ page->scroll_idx = scroll_idx; page->scroll_num = scroll_num; } /** * term_history_new() - Create new history object * @out: storage for pointer to new history * * Create a new history object. Histories are used to store scrollback-lines * from VTE pages. You're highly recommended to set a history-limit on * history->max_lines and trim it via term_history_trim(), otherwise history * allocations are unlimited. * * Returns: 0 on success, negative error code on failure. */ int term_history_new(term_history **out) { _term_history_free_ term_history *history = NULL; assert_return(out, -EINVAL); history = new0(term_history, 1); if (!history) return -ENOMEM; history->max_lines = 4096; *out = history; history = NULL; return 0; } /** * term_history_free() - Free history * @history: history to free * * Clear and free history. You must not access the object afterwards. * * Returns: NULL */ term_history *term_history_free(term_history *history) { if (!history) return NULL; term_history_clear(history); free(history); return NULL; } /** * term_history_clear() - Clear history * @history: history to clear * * Remove all linked lines from a history and reset it to its initial state. */ void term_history_clear(term_history *history) { return term_history_trim(history, 0); } /** * term_history_trim() - Trim history * @history: history to trim * @max: maximum number of lines to be left in history * * This removes lines from the history until it is smaller than @max. Lines are * removed from the top. */ void term_history_trim(term_history *history, unsigned int max) { term_line *line; if (!history) return; while (history->n_lines > max && (line = history->lines_first)) { TERM_LINE_UNLINK(line, history); term_line_free(line); --history->n_lines; } } /** * term_history_push() - Push line into history * @history: history to work on * @line: line to push into history * * This pushes a line into the given history. It is linked at the tail. In case * the history is limited, the top-most line might be freed. */ void term_history_push(term_history *history, term_line *line) { assert(history); assert(line); TERM_LINE_LINK_TAIL(line, history); if (history->max_lines > 0 && history->n_lines >= history->max_lines) { line = history->lines_first; TERM_LINE_UNLINK(line, history); term_line_free(line); } else { ++history->n_lines; } } /** * term_history_pop() - Retrieve last line from history * @history: history to work on * @new_width: width to reserve and set on the line * @attr: attributes to use for cell reservation * @age: age to use for cell reservation * * This unlinks the last linked line of the history and returns it. This also * makes sure the line has the given width pre-allocated (see * term_line_reserve()). If the pre-allocation fails, this returns NULL, so it * is treated like there's no line in history left. This simplifies * history-handling on the caller's side in case of allocation errors. No need * to throw lines away just because the reservation failed. We can keep them in * history safely, and make them available as scrollback. * * Returns: Line from history or NULL */ term_line *term_history_pop(term_history *history, unsigned int new_width, const term_attr *attr, term_age_t age) { term_line *line; int r; assert_return(history, NULL); line = history->lines_last; if (!line) return NULL; r = term_line_reserve(line, new_width, attr, age, line->width); if (r < 0) return NULL; term_line_set_width(line, new_width); TERM_LINE_UNLINK(line, history); --history->n_lines; return line; } /** * term_history_peek() - Return number of available history-lines * @history: history to work on * @max: maximum number of lines to look at * @reserve_width: width to reserve on the line * @attr: attributes to use for cell reservation * @age: age to use for cell reservation * * This returns the number of available lines in the history given as @history. * It returns at most @max. For each line that is looked at, the line is * verified to have at least @reserve_width cells. Valid cells are preserved, * new cells are initialized with @attr and @age. In case an allocation fails, * we bail out and return the number of lines that are valid so far. * * Usually, this function should be used before running a loop on * term_history_pop(). This function guarantees that term_history_pop() (with * the same arguments) will succeed at least the returned number of times. * * Returns: Number of valid lines that can be received via term_history_pop(). */ unsigned int term_history_peek(term_history *history, unsigned int max, unsigned int reserve_width, const term_attr *attr, term_age_t age) { unsigned int num; term_line *line; int r; assert(history); num = 0; line = history->lines_last; while (num < max && line) { r = term_line_reserve(line, reserve_width, attr, age, line->width); if (r < 0) break; ++num; line = line->lines_prev; } return num; }