Add initial infrastructure for Profiling

The EosProfileProbe API allows defining profiling probes that can be
used to efficiently measure the time spent in a critical section.

The Profiling API is meant to collect samples and generate a report
at the end of the lifetime of the process, either by printing out the
results once the process terminates; or by saving the raw data in a
binary file that can be loaded at a later date.

This profiling API is meant to be as close as possible to a zero cost
abstraction:

 - probes are only allocated if profiling is enabled
 - all profiling API is a no-op if profiling isn't enabled
 - the C API is meant to be easily tied to a scope, through the
   use of auto-cleanup macros provided by GLib

This allows projects using the Endless SDK to keep the profiling probes
in place, instead of conditionally compile them in.

https://phabricator.endlessm.com/T18514

1 files changed, 36 insertions, 0 deletions

diff --git a/endless/eosprofile-private.h b/endless/eosprofile-private.h
new file mode 100644
index 0000000..a07de0e
--- /dev/null
+++ b/endless/eosprofile-private.h
@@ -0,0 +1,36 @@
+/* Copyright 2017  Endless */
+
+#pragma once
+
+#include "eosprofile.h"
+
+G_BEGIN_DECLS
+
+/* Increase every time the probe format changes */
+#define PROBE_DB_VERSION                1
+
+#define PROBE_DB_META_BASE_KEY          "/com/endlessm/Sdk/meta"
+#define PROBE_DB_META_VERSION_KEY       PROBE_DB_META_BASE_KEY "/db_version"
+
+typedef struct {
+  GHashTable *probes;
+
+  gboolean capture;
+  char *capture_file;
+} ProfileState;
+
+G_LOCK_DEFINE_STATIC (profile_state);
+static ProfileState *profile_state;
+
+typedef struct {
+  gint64 start_time;
+  gint64 end_time;
+} ProfileSample;
+
+void
+eos_profile_state_init (void);
+
+void
+eos_profile_state_dump (void);
+
+G_END_DECLS