Added `--verbose` flag for debugging output in PDF production.

Closes #1840.
Closes #1653.

4 files changed, 42 insertions, 10 deletions

diff --git a/README b/README
index dcc892bff..b54107f32 100644
--- a/README
+++ b/README
@@ -230,6 +230,10 @@ General options
     `epub.css`, `templates`, `slidy`, `slideous`, or `s5` directory
     placed in this directory will override pandoc's normal defaults.
 
+`--verbose`
+:   Give verbose debugging output.  Currently this only has an effect
+    with PDF output.
+
 `-v`, `--version`
 :   Print version.
 
diff --git a/pandoc.hs b/pandoc.hs
index 7b910be71..1ae8262c3 100644
--- a/pandoc.hs
+++ b/pandoc.hs
@@ -186,6 +186,7 @@ data Opt = Opt
     , optTOCDepth          :: Int     -- ^ Number of levels to include in TOC
     , optDumpArgs          :: Bool    -- ^ Output command-line arguments
     , optIgnoreArgs        :: Bool    -- ^ Ignore command-line arguments
+    , optVerbose           :: Bool    -- ^ Verbose diagnostic output
     , optReferenceLinks    :: Bool    -- ^ Use reference links in writing markdown, rst
     , optWrapText          :: Bool    -- ^ Wrap text
     , optColumns           :: Int     -- ^ Line length in characters
@@ -246,6 +247,7 @@ defaultOpts = Opt
     , optTOCDepth              = 3
     , optDumpArgs              = False
     , optIgnoreArgs            = False
+    , optVerbose               = False
     , optReferenceLinks        = False
     , optWrapText              = True
     , optColumns               = 72
@@ -858,6 +860,11 @@ options =
                   (\opt -> return opt { optIgnoreArgs = True }))
                  "" -- "Ignore command-line arguments."
 
+    , Option "" ["verbose"]
+                 (NoArg
+                  (\opt -> return opt { optVerbose = True }))
+                 "" -- "Verbose diagnostic output."
+
     , Option "v" ["version"]
                  (NoArg
                   (\_ -> do
@@ -1061,6 +1068,7 @@ main = do
               , optTOCDepth              = epubTOCDepth
               , optDumpArgs              = dumpArgs
               , optIgnoreArgs            = ignoreArgs
+              , optVerbose               = verbose
               , optReferenceLinks        = referenceLinks
               , optWrapText              = wrap
               , optColumns               = columns
@@ -1302,7 +1310,8 @@ main = do
                             writerTOCDepth         = epubTOCDepth,
                             writerReferenceODT     = referenceODT,
                             writerReferenceDocx    = referenceDocx,
-                            writerMediaBag         = media
+                            writerMediaBag         = media,
+                            writerVerbose          = verbose
                           }
 
 
diff --git a/src/Text/Pandoc/Options.hs b/src/Text/Pandoc/Options.hs
index ebfd8f8a9..24e31fbb6 100644
--- a/src/Text/Pandoc/Options.hs
+++ b/src/Text/Pandoc/Options.hs
@@ -323,6 +323,7 @@ data WriterOptions = WriterOptions
   , writerReferenceODT     :: Maybe FilePath -- ^ Path to reference ODT if specified
   , writerReferenceDocx    :: Maybe FilePath -- ^ Path to reference DOCX if specified
   , writerMediaBag         :: MediaBag       -- ^ Media collected by docx or epub reader
+  , writerVerbose          :: Bool           -- ^ Verbose debugging output
   } deriving Show
 
 instance Default WriterOptions where
@@ -366,6 +367,7 @@ instance Default WriterOptions where
                       , writerReferenceODT     = Nothing
                       , writerReferenceDocx    = Nothing
                       , writerMediaBag         = mempty
+                      , writerVerbose          = False
                       }
 
 -- | Returns True if the given extension is enabled.
diff --git a/src/Text/Pandoc/PDF.hs b/src/Text/Pandoc/PDF.hs
index d5f7c609d..75bd489d1 100644
--- a/src/Text/Pandoc/PDF.hs
+++ b/src/Text/Pandoc/PDF.hs
@@ -36,10 +36,11 @@ import qualified Data.ByteString.Lazy.Char8 as BC
 import qualified Data.ByteString as BS
 import System.Exit (ExitCode (..))
 import System.FilePath
+import System.IO (stderr, stdout)
 import System.Directory
 import Data.Digest.Pure.SHA (showDigest, sha1)
 import System.Environment
-import Control.Monad (unless, (<=<))
+import Control.Monad (unless, when, (<=<))
 import qualified Control.Exception as E
 import Control.Applicative ((<$))
 import Data.List (isInfixOf)
@@ -70,7 +71,7 @@ makePDF :: String              -- ^ pdf creator (pdflatex, lualatex, xelatex)
 makePDF program writer opts doc = withTempDir "tex2pdf." $ \tmpdir -> do
   doc' <- handleImages opts tmpdir doc
   let source = writer opts doc'
-  tex2pdf' tmpdir program source
+  tex2pdf' (writerVerbose opts) tmpdir program source
 
 handleImages :: WriterOptions
              -> FilePath      -- ^ temp dir to store images
@@ -130,15 +131,16 @@ convertImage tmpdir fname =
     mime = getMimeType fname
     doNothing = return (Right fname)
 
-tex2pdf' :: FilePath                        -- ^ temp directory for output
+tex2pdf' :: Bool                            -- ^ Verbose output
+         -> FilePath                        -- ^ temp directory for output
          -> String                          -- ^ tex program
          -> String                          -- ^ tex source
          -> IO (Either ByteString ByteString)
-tex2pdf' tmpDir program source = do
+tex2pdf' verbose tmpDir program source = do
   let numruns = if "\\tableofcontents" `isInfixOf` source
                    then 3  -- to get page numbers
                    else 2  -- 1 run won't give you PDF bookmarks
-  (exit, log', mbPdf) <- runTeXProgram program numruns tmpDir source
+  (exit, log', mbPdf) <- runTeXProgram verbose program 1 numruns tmpDir source
   case (exit, mbPdf) of
        (ExitFailure _, _)      -> do
           let logmsg = extractMsg log'
@@ -170,9 +172,9 @@ extractMsg log' = do
 -- Run a TeX program on an input bytestring and return (exit code,
 -- contents of stdout, contents of produced PDF if any).  Rerun
 -- a fixed number of times to resolve references.
-runTeXProgram :: String -> Int -> FilePath -> String
+runTeXProgram :: Bool -> String -> Int -> Int -> FilePath -> String
               -> IO (ExitCode, ByteString, Maybe ByteString)
-runTeXProgram program runsLeft tmpDir source = do
+runTeXProgram verbose program runNumber numRuns tmpDir source = do
     let file = tmpDir </> "input.tex"
     exists <- doesFileExist file
     unless exists $ UTF8.writeFile file source
@@ -192,9 +194,24 @@ runTeXProgram program runsLeft tmpDir source = do
           $ lookup "TEXINPUTS" env'
     let env'' = ("TEXINPUTS", texinputs) :
                   [(k,v) | (k,v) <- env', k /= "TEXINPUTS"]
+    when (verbose && runNumber == 1) $ do
+      putStrLn $ "[makePDF] Command line:"
+      putStrLn $ program ++ " " ++ unwords (map show programArgs)
+      putStr "\n"
+      putStrLn $ "[makePDF] Environment:"
+      mapM_ print env''
+      putStr "\n"
+      putStrLn $ "[makePDF] Contents of " ++ file' ++ ":"
+      B.readFile file' >>= B.putStr
+      putStr "\n"
     (exit, out, err) <- pipeProcess (Just env'') program programArgs BL.empty
-    if runsLeft > 1
-       then runTeXProgram program (runsLeft - 1) tmpDir source
+    when verbose $ do
+      putStrLn $ "[makePDF] Run #" ++ show runNumber
+      B.hPutStr stdout out
+      B.hPutStr stderr err
+      putStr "\n"
+    if runNumber <= numRuns
+       then runTeXProgram verbose program (runNumber + 1) numRuns tmpDir source
        else do
          let pdfFile = replaceDirectory (replaceExtension file ".pdf") tmpDir
          pdfExists <- doesFileExist pdfFile