summaryrefslogtreecommitdiffstats
path: root/src/shell-perf-log.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/shell-perf-log.c')
-rw-r--r--src/shell-perf-log.c959
1 files changed, 959 insertions, 0 deletions
diff --git a/src/shell-perf-log.c b/src/shell-perf-log.c
new file mode 100644
index 0000000..e108a26
--- /dev/null
+++ b/src/shell-perf-log.c
@@ -0,0 +1,959 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+#include "config.h"
+
+#include <string.h>
+
+#include "shell-perf-log.h"
+
+typedef struct _ShellPerfEvent ShellPerfEvent;
+typedef struct _ShellPerfStatistic ShellPerfStatistic;
+typedef struct _ShellPerfStatisticsClosure ShellPerfStatisticsClosure;
+typedef union _ShellPerfStatisticValue ShellPerfStatisticValue;
+typedef struct _ShellPerfBlock ShellPerfBlock;
+
+/**
+ * SECTION:shell-perf-log
+ * @short_description: Event recorder for performance measurement
+ *
+ * ShellPerfLog provides a way for different parts of the code to
+ * record information for subsequent analysis and interactive
+ * exploration. Events exist of a timestamp, an event ID, and
+ * arguments to the event.
+ *
+ * Emphasis is placed on storing recorded events in a compact
+ * fashion so log recording disturbs the execution of the program
+ * as little as possible, however events should not be recorded
+ * at too fine a granularity - an event that is recorded once
+ * per frame or once per user action is appropriate, an event that
+ * occurs many times per frame is not.
+ *
+ * Arguments are identified by a D-Bus style signature; at the moment
+ * only a limited number of event signatures are supported to
+ * simplify the code.
+ */
+struct _ShellPerfLog
+{
+ GObject parent;
+
+ GPtrArray *events;
+ GHashTable *events_by_name;
+ GPtrArray *statistics;
+ GHashTable *statistics_by_name;
+
+ GPtrArray *statistics_closures;
+
+ GQueue *blocks;
+
+ gint64 start_time;
+ gint64 last_time;
+
+ guint statistics_timeout_id;
+
+ guint enabled : 1;
+};
+
+struct _ShellPerfEvent
+{
+ guint16 id;
+ char *name;
+ char *description;
+ char *signature;
+};
+
+union _ShellPerfStatisticValue
+{
+ int i;
+ gint64 x;
+};
+
+struct _ShellPerfStatistic
+{
+ ShellPerfEvent *event;
+
+ ShellPerfStatisticValue current_value;
+ ShellPerfStatisticValue last_value;
+
+ guint initialized : 1;
+ guint recorded : 1;
+};
+
+struct _ShellPerfStatisticsClosure
+{
+ ShellPerfStatisticsCallback callback;
+ gpointer user_data;
+ GDestroyNotify notify;
+};
+
+/* The events in the log are stored in a linked list of fixed size
+ * blocks.
+ *
+ * Note that the power-of-two nature of BLOCK_SIZE here is superficial
+ * since the allocated block has the 'bytes' field and malloc
+ * overhead. The current value is well below the size that will
+ * typically be independently mmapped by the malloc implementation so
+ * it doesn't matter. If we switched to mmapping blocks manually
+ * (perhaps to avoid polluting malloc statistics), we'd want to use a
+ * different value of BLOCK_SIZE.
+ */
+#define BLOCK_SIZE 8192
+
+struct _ShellPerfBlock
+{
+ guint32 bytes;
+ guchar buffer[BLOCK_SIZE];
+};
+
+/* Number of milliseconds between periodic statistics collection when
+ * events are enabled. Statistics collection can also be explicitly
+ * triggered.
+ */
+#define STATISTIC_COLLECTION_INTERVAL_MS 5000
+
+/* Builtin events */
+enum {
+ EVENT_SET_TIME,
+ EVENT_STATISTICS_COLLECTED
+};
+
+G_DEFINE_TYPE(ShellPerfLog, shell_perf_log, G_TYPE_OBJECT);
+
+static gint64
+get_time (void)
+{
+ return g_get_monotonic_time ();
+}
+
+static void
+shell_perf_log_init (ShellPerfLog *perf_log)
+{
+ perf_log->events = g_ptr_array_new ();
+ perf_log->events_by_name = g_hash_table_new (g_str_hash, g_str_equal);
+ perf_log->statistics = g_ptr_array_new ();
+ perf_log->statistics_by_name = g_hash_table_new (g_str_hash, g_str_equal);
+ perf_log->statistics_closures = g_ptr_array_new ();
+ perf_log->blocks = g_queue_new ();
+
+ /* This event is used when timestamp deltas are greater than
+ * fits in a gint32. 0xffffffff microseconds is about 70 minutes, so this
+ * is not going to happen in normal usage. It might happen if performance
+ * logging is enabled some time after starting the shell */
+ shell_perf_log_define_event (perf_log, "perf.setTime", "", "x");
+ g_assert (perf_log->events->len == EVENT_SET_TIME + 1);
+
+ /* The purpose of this event is to allow us to optimize out storing
+ * statistics that haven't changed. We want to mark every time we
+ * collect statistics even if we don't record any individual
+ * statistics so that we can distinguish sudden changes from gradual changes.
+ *
+ * The argument is the number of microseconds that statistics collection
+ * took; we record that since statistics collection could start taking
+ * significant time if we do things like grub around in /proc/
+ */
+ shell_perf_log_define_event (perf_log, "perf.statisticsCollected",
+ "Finished collecting statistics",
+ "x");
+ g_assert (perf_log->events->len == EVENT_STATISTICS_COLLECTED + 1);
+
+ perf_log->start_time = perf_log->last_time = get_time();
+}
+
+static void
+shell_perf_log_class_init (ShellPerfLogClass *class)
+{
+}
+
+/**
+ * shell_perf_log_get_default:
+ *
+ * Gets the global singleton performance log. This is initially disabled
+ * and must be explicitly enabled with shell_perf_log_set_enabled().
+ *
+ * Return value: (transfer none): the global singleton performance log
+ */
+ShellPerfLog *
+shell_perf_log_get_default (void)
+{
+ static ShellPerfLog *perf_log;
+
+ if (perf_log == NULL)
+ perf_log = g_object_new (SHELL_TYPE_PERF_LOG, NULL);
+
+ return perf_log;
+}
+
+static gboolean
+statistics_timeout (gpointer data)
+{
+ ShellPerfLog *perf_log = data;
+
+ shell_perf_log_collect_statistics (perf_log);
+
+ return TRUE;
+}
+
+/**
+ * shell_perf_log_set_enabled:
+ * @perf_log: a #ShellPerfLog
+ * @enabled: whether to record events
+ *
+ * Sets whether events are currently being recorded.
+ */
+void
+shell_perf_log_set_enabled (ShellPerfLog *perf_log,
+ gboolean enabled)
+{
+ enabled = enabled != FALSE;
+
+ if (enabled != perf_log->enabled)
+ {
+ perf_log->enabled = enabled;
+
+ if (enabled)
+ {
+ perf_log->statistics_timeout_id = g_timeout_add (STATISTIC_COLLECTION_INTERVAL_MS,
+ statistics_timeout,
+ perf_log);
+ g_source_set_name_by_id (perf_log->statistics_timeout_id, "[gnome-shell] statistics_timeout");
+ }
+ else
+ {
+ g_clear_handle_id (&perf_log->statistics_timeout_id, g_source_remove);
+ }
+ }
+}
+
+static ShellPerfEvent *
+define_event (ShellPerfLog *perf_log,
+ const char *name,
+ const char *description,
+ const char *signature)
+{
+ ShellPerfEvent *event;
+
+ if (strcmp (signature, "") != 0 &&
+ strcmp (signature, "s") != 0 &&
+ strcmp (signature, "i") != 0 &&
+ strcmp (signature, "x") != 0)
+ {
+ g_warning ("Only supported event signatures are '', 's', 'i', and 'x'\n");
+ return NULL;
+ }
+
+ if (perf_log->events->len == 65536)
+ {
+ g_warning ("Maximum number of events defined\n");
+ return NULL;
+ }
+
+ /* We could do stricter validation, but this will break our JSON dumps */
+ if (strchr (name, '"') != NULL)
+ {
+ g_warning ("Event names can't include '\"'");
+ return NULL;
+ }
+
+ if (g_hash_table_lookup (perf_log->events_by_name, name) != NULL)
+ {
+ g_warning ("Duplicate event event for '%s'\n", name);
+ return NULL;
+ }
+
+ event = g_slice_new (ShellPerfEvent);
+
+ event->id = perf_log->events->len;
+ event->name = g_strdup (name);
+ event->signature = g_strdup (signature);
+ event->description = g_strdup (description);
+
+ g_ptr_array_add (perf_log->events, event);
+ g_hash_table_insert (perf_log->events_by_name, event->name, event);
+
+ return event;
+}
+
+/**
+ * shell_perf_log_define_event:
+ * @perf_log: a #ShellPerfLog
+ * @name: name of the event. This should of the form
+ * '<namespace>.<specific eventf'>, for example
+ * 'clutter.stagePaintDone'.
+ * @description: human readable description of the event.
+ * @signature: signature defining the arguments that event takes.
+ * This is a string of type characters, using the same characters
+ * as D-Bus or GVariant. Only a very limited number of signatures
+ * are supported: , '', 's', 'i', and 'x'. This mean respectively:
+ * no arguments, one string, one 32-bit integer, and one 64-bit
+ * integer.
+ *
+ * Defines a performance event for later recording.
+ */
+void
+shell_perf_log_define_event (ShellPerfLog *perf_log,
+ const char *name,
+ const char *description,
+ const char *signature)
+{
+ define_event (perf_log, name, description, signature);
+}
+
+static ShellPerfEvent *
+lookup_event (ShellPerfLog *perf_log,
+ const char *name,
+ const char *signature)
+{
+ ShellPerfEvent *event = g_hash_table_lookup (perf_log->events_by_name, name);
+
+ if (G_UNLIKELY (event == NULL))
+ {
+ g_warning ("Discarding unknown event '%s'\n", name);
+ return NULL;
+ }
+
+ if (G_UNLIKELY (strcmp (event->signature, signature) != 0))
+ {
+ g_warning ("Event '%s'; defined with signature '%s', used with '%s'\n",
+ name, event->signature, signature);
+ return NULL;
+ }
+
+ return event;
+}
+
+static void
+record_event (ShellPerfLog *perf_log,
+ gint64 event_time,
+ ShellPerfEvent *event,
+ const guchar *bytes,
+ size_t bytes_len)
+{
+ ShellPerfBlock *block;
+ size_t total_bytes;
+ guint32 time_delta;
+ guint32 pos;
+
+ if (!perf_log->enabled)
+ return;
+
+ total_bytes = sizeof (gint32) + sizeof (gint16) + bytes_len;
+ if (G_UNLIKELY (bytes_len > BLOCK_SIZE || total_bytes > BLOCK_SIZE))
+ {
+ g_warning ("Discarding oversize event '%s'\n", event->name);
+ return;
+ }
+
+ if (event_time > perf_log->last_time + G_GINT64_CONSTANT(0xffffffff))
+ {
+ perf_log->last_time = event_time;
+ record_event (perf_log, event_time,
+ lookup_event (perf_log, "perf.setTime", "x"),
+ (const guchar *)&event_time, sizeof(gint64));
+ time_delta = 0;
+ }
+ else if (event_time < perf_log->last_time)
+ time_delta = 0;
+ else
+ time_delta = (guint32)(event_time - perf_log->last_time);
+
+ perf_log->last_time = event_time;
+
+ if (perf_log->blocks->tail == NULL ||
+ total_bytes + ((ShellPerfBlock *)perf_log->blocks->tail->data)->bytes > BLOCK_SIZE)
+ {
+ block = g_new (ShellPerfBlock, 1);
+ block->bytes = 0;
+ g_queue_push_tail (perf_log->blocks, block);
+ }
+ else
+ {
+ block = (ShellPerfBlock *)perf_log->blocks->tail->data;
+ }
+
+ pos = block->bytes;
+
+ memcpy (block->buffer + pos, &time_delta, sizeof (guint32));
+ pos += sizeof (guint32);
+ memcpy (block->buffer + pos, &event->id, sizeof (guint16));
+ pos += sizeof (guint16);
+ memcpy (block->buffer + pos, bytes, bytes_len);
+ pos += bytes_len;
+
+ block->bytes = pos;
+}
+
+/**
+ * shell_perf_log_event:
+ * @perf_log: a #ShellPerfLog
+ * @name: name of the event
+ *
+ * Records a performance event with no arguments.
+ */
+void
+shell_perf_log_event (ShellPerfLog *perf_log,
+ const char *name)
+{
+ ShellPerfEvent *event = lookup_event (perf_log, name, "");
+ if (G_UNLIKELY (event == NULL))
+ return;
+
+ record_event (perf_log, get_time(), event, NULL, 0);
+}
+
+/**
+ * shell_perf_log_event_i:
+ * @perf_log: a #ShellPerfLog
+ * @name: name of the event
+ * @arg: the argument
+ *
+ * Records a performance event with one 32-bit integer argument.
+ */
+void
+shell_perf_log_event_i (ShellPerfLog *perf_log,
+ const char *name,
+ gint32 arg)
+{
+ ShellPerfEvent *event = lookup_event (perf_log, name, "i");
+ if (G_UNLIKELY (event == NULL))
+ return;
+
+ record_event (perf_log, get_time(), event,
+ (const guchar *)&arg, sizeof (arg));
+}
+
+/**
+ * shell_perf_log_event_x:
+ * @perf_log: a #ShellPerfLog
+ * @name: name of the event
+ * @arg: the argument
+ *
+ * Records a performance event with one 64-bit integer argument.
+ */
+void
+shell_perf_log_event_x (ShellPerfLog *perf_log,
+ const char *name,
+ gint64 arg)
+{
+ ShellPerfEvent *event = lookup_event (perf_log, name, "x");
+ if (G_UNLIKELY (event == NULL))
+ return;
+
+ record_event (perf_log, get_time(), event,
+ (const guchar *)&arg, sizeof (arg));
+}
+
+/**
+ * shell_perf_log_event_s:
+ * @perf_log: a #ShellPerfLog
+ * @name: name of the event
+ * @arg: the argument
+ *
+ * Records a performance event with one string argument.
+ */
+void
+shell_perf_log_event_s (ShellPerfLog *perf_log,
+ const char *name,
+ const char *arg)
+{
+ ShellPerfEvent *event = lookup_event (perf_log, name, "s");
+ if (G_UNLIKELY (event == NULL))
+ return;
+
+ record_event (perf_log, get_time(), event,
+ (const guchar *)arg, strlen (arg) + 1);
+}
+
+/**
+ * shell_perf_log_define_statistic:
+ * @name: name of the statistic and of the corresponding event.
+ * This should follow the same guidelines as for shell_perf_log_define_event()
+ * @description: human readable description of the statistic.
+ * @signature: The type of the data stored for statistic. Must
+ * currently be 'i' or 'x'.
+ *
+ * Defines a statistic. A statistic is a numeric value that is stored
+ * by the performance log and recorded periodically or when
+ * shell_perf_log_collect_statistics() is called explicitly.
+ *
+ * Code that defines a statistic should update it by calling
+ * the update function for the particular data type of the statistic,
+ * such as shell_perf_log_update_statistic_i(). This can be done
+ * at any time, but would normally done inside a function registered
+ * with shell_perf_log_add_statistics_callback(). These functions
+ * are called immediately before statistics are recorded.
+ */
+void
+shell_perf_log_define_statistic (ShellPerfLog *perf_log,
+ const char *name,
+ const char *description,
+ const char *signature)
+{
+ ShellPerfEvent *event;
+ ShellPerfStatistic *statistic;
+
+ if (strcmp (signature, "i") != 0 &&
+ strcmp (signature, "x") != 0)
+ {
+ g_warning ("Only supported statistic signatures are 'i' and 'x'\n");
+ return;
+ }
+
+ event = define_event (perf_log, name, description, signature);
+ if (event == NULL)
+ return;
+
+ statistic = g_slice_new (ShellPerfStatistic);
+ statistic->event = event;
+
+ statistic->initialized = FALSE;
+ statistic->recorded = FALSE;
+
+ g_ptr_array_add (perf_log->statistics, statistic);
+ g_hash_table_insert (perf_log->statistics_by_name, event->name, statistic);
+}
+
+static ShellPerfStatistic *
+lookup_statistic (ShellPerfLog *perf_log,
+ const char *name,
+ const char *signature)
+{
+ ShellPerfStatistic *statistic = g_hash_table_lookup (perf_log->statistics_by_name, name);
+
+ if (G_UNLIKELY (statistic == NULL))
+ {
+ g_warning ("Unknown statistic '%s'\n", name);
+ return NULL;
+ }
+
+ if (G_UNLIKELY (strcmp (statistic->event->signature, signature) != 0))
+ {
+ g_warning ("Statistic '%s'; defined with signature '%s', used with '%s'\n",
+ name, statistic->event->signature, signature);
+ return NULL;
+ }
+
+ return statistic;
+}
+
+/**
+ * shell_perf_log_update_statistic_i:
+ * @perf_log: a #ShellPerfLog
+ * @name: name of the statistic
+ * @value: new value for the statistic
+ *
+ * Updates the current value of an 32-bit integer statistic.
+ */
+void
+shell_perf_log_update_statistic_i (ShellPerfLog *perf_log,
+ const char *name,
+ gint32 value)
+{
+ ShellPerfStatistic *statistic;
+
+ statistic = lookup_statistic (perf_log, name, "i");
+ if (G_UNLIKELY (statistic == NULL))
+ return;
+
+ statistic->current_value.i = value;
+ statistic->initialized = TRUE;
+}
+
+/**
+ * shell_perf_log_update_statistic_x:
+ * @perf_log: a #ShellPerfLog
+ * @name: name of the statistic
+ * @value: new value for the statistic
+ *
+ * Updates the current value of an 64-bit integer statistic.
+ */
+void
+shell_perf_log_update_statistic_x (ShellPerfLog *perf_log,
+ const char *name,
+ gint64 value)
+{
+ ShellPerfStatistic *statistic;
+
+ statistic = lookup_statistic (perf_log, name, "x");
+ if (G_UNLIKELY (statistic == NULL))
+ return;
+
+ statistic->current_value.x = value;
+ statistic->initialized = TRUE;
+}
+
+/**
+ * shell_perf_log_add_statistics_callback:
+ * @perf_log: a #ShellPerfLog
+ * @callback: function to call before recording statistics
+ * @user_data: data to pass to @callback
+ * @notify: function to call when @user_data is no longer needed
+ *
+ * Adds a function that will be called before statistics are recorded.
+ * The function would typically compute one or more statistics values
+ * and call a function such as shell_perf_log_update_statistic_i()
+ * to update the value that will be recorded.
+ */
+void
+shell_perf_log_add_statistics_callback (ShellPerfLog *perf_log,
+ ShellPerfStatisticsCallback callback,
+ gpointer user_data,
+ GDestroyNotify notify)
+{
+ ShellPerfStatisticsClosure *closure = g_slice_new (ShellPerfStatisticsClosure);
+
+ closure->callback = callback;
+ closure->user_data = user_data;
+ closure->notify = notify;
+
+ g_ptr_array_add (perf_log->statistics_closures, closure);
+}
+
+/**
+ * shell_perf_log_collect_statistics:
+ * @perf_log: a #ShellPerfLog
+ *
+ * Calls all the update functions added with
+ * shell_perf_log_add_statistics_callback() and then records events
+ * for all statistics, followed by a perf.statisticsCollected event.
+ */
+void
+shell_perf_log_collect_statistics (ShellPerfLog *perf_log)
+{
+ gint64 event_time = get_time ();
+ gint64 collection_time;
+ guint i;
+
+ if (!perf_log->enabled)
+ return;
+
+ for (i = 0; i < perf_log->statistics_closures->len; i++)
+ {
+ ShellPerfStatisticsClosure *closure;
+
+ closure = g_ptr_array_index (perf_log->statistics_closures, i);
+ closure->callback (perf_log, closure->user_data);
+ }
+
+ collection_time = get_time() - event_time;
+
+ for (i = 0; i < perf_log->statistics->len; i++)
+ {
+ ShellPerfStatistic *statistic = g_ptr_array_index (perf_log->statistics, i);
+
+ if (!statistic->initialized)
+ continue;
+
+ switch (statistic->event->signature[0])
+ {
+ case 'i':
+ if (!statistic->recorded ||
+ statistic->current_value.i != statistic->last_value.i)
+ {
+ record_event (perf_log, event_time, statistic->event,
+ (const guchar *)&statistic->current_value.i,
+ sizeof (gint32));
+ statistic->last_value.i = statistic->current_value.i;
+ statistic->recorded = TRUE;
+ }
+ break;
+ case 'x':
+ if (!statistic->recorded ||
+ statistic->current_value.x != statistic->last_value.x)
+ {
+ record_event (perf_log, event_time, statistic->event,
+ (const guchar *)&statistic->current_value.x,
+ sizeof (gint64));
+ statistic->last_value.x = statistic->current_value.x;
+ statistic->recorded = TRUE;
+ }
+ break;
+ default:
+ g_warning ("Unsupported signature in event");
+ break;
+ }
+ }
+
+ record_event (perf_log, event_time,
+ g_ptr_array_index (perf_log->events, EVENT_STATISTICS_COLLECTED),
+ (const guchar *)&collection_time, sizeof (gint64));
+}
+
+/**
+ * shell_perf_log_replay:
+ * @perf_log: a #ShellPerfLog
+ * @replay_function: (scope call): function to call for each event in the log
+ * @user_data: data to pass to @replay_function
+ *
+ * Replays the log by calling the given function for each event
+ * in the log.
+ */
+void
+shell_perf_log_replay (ShellPerfLog *perf_log,
+ ShellPerfReplayFunction replay_function,
+ gpointer user_data)
+{
+ gint64 event_time = perf_log->start_time;
+ GList *iter;
+
+ for (iter = perf_log->blocks->head; iter; iter = iter->next)
+ {
+ ShellPerfBlock *block = iter->data;
+ guint32 pos = 0;
+
+ while (pos < block->bytes)
+ {
+ ShellPerfEvent *event;
+ guint16 id;
+ guint32 time_delta;
+ GValue arg = { 0, };
+
+ memcpy (&time_delta, block->buffer + pos, sizeof (guint32));
+ pos += sizeof (guint32);
+ memcpy (&id, block->buffer + pos, sizeof (guint16));
+ pos += sizeof (guint16);
+
+ if (id == EVENT_SET_TIME)
+ {
+ /* Internal, we don't include in the replay */
+ memcpy (&event_time, block->buffer + pos, sizeof (gint64));
+ pos += sizeof (gint64);
+ continue;
+ }
+ else
+ {
+ event_time += time_delta;
+ }
+
+ event = g_ptr_array_index (perf_log->events, id);
+
+ if (strcmp (event->signature, "") == 0)
+ {
+ /* We need to pass something, so pass an empty string */
+ g_value_init (&arg, G_TYPE_STRING);
+ }
+ else if (strcmp (event->signature, "i") == 0)
+ {
+ gint32 l;
+
+ memcpy (&l, block->buffer + pos, sizeof (gint32));
+ pos += sizeof (gint32);
+
+ g_value_init (&arg, G_TYPE_INT);
+ g_value_set_int (&arg, l);
+ }
+ else if (strcmp (event->signature, "x") == 0)
+ {
+ gint64 l;
+
+ memcpy (&l, block->buffer + pos, sizeof (gint64));
+ pos += sizeof (gint64);
+
+ g_value_init (&arg, G_TYPE_INT64);
+ g_value_set_int64 (&arg, l);
+ }
+ else if (strcmp (event->signature, "s") == 0)
+ {
+ g_value_init (&arg, G_TYPE_STRING);
+ g_value_set_string (&arg, (char *)block->buffer + pos);
+ pos += strlen ((char *)(block->buffer + pos)) + 1;
+ }
+
+ replay_function (event_time, event->name, event->signature, &arg, user_data);
+ g_value_unset (&arg);
+ }
+ }
+}
+
+static char *
+escape_quotes (const char *input)
+{
+ GString *result;
+ const char *p;
+
+ if (strchr (input, '"') == NULL)
+ return (char *)input;
+
+ result = g_string_new (NULL);
+ for (p = input; *p; p++)
+ {
+ if (*p == '"')
+ g_string_append (result, "\\\"");
+ else
+ g_string_append_c (result, *p);
+ }
+
+ return g_string_free (result, FALSE);
+}
+
+static gboolean
+write_string (GOutputStream *out,
+ const char *str,
+ GError **error)
+{
+ return g_output_stream_write_all (out, str, strlen (str),
+ NULL, NULL,
+ error);
+}
+
+/**
+ * shell_perf_log_dump_events:
+ * @perf_log: a #ShellPerfLog
+ * @out: output stream into which to write the event definitions
+ * @error: location to store #GError, or %NULL
+ *
+ * Dump the definition of currently defined events and statistics, formatted
+ * as JSON, to the specified output stream. The JSON output is an array,
+ * with each element being a dictionary of the form:
+ *
+ * { name: <name of event>,
+ * description: <description of string,
+ * statistic: true } (only for statistics)
+ *
+ * Return value: %TRUE if the dump succeeded. %FALSE if an IO error occurred
+ */
+gboolean
+shell_perf_log_dump_events (ShellPerfLog *perf_log,
+ GOutputStream *out,
+ GError **error)
+{
+ GString *output;
+ guint i;
+
+ output = g_string_new (NULL);
+ g_string_append (output, "[ ");
+
+ for (i = 0; i < perf_log->events->len; i++)
+ {
+ ShellPerfEvent *event = g_ptr_array_index (perf_log->events, i);
+ char *escaped_description = escape_quotes (event->description);
+ gboolean is_statistic = g_hash_table_lookup (perf_log->statistics_by_name, event->name) != NULL;
+
+ if (i != 0)
+ g_string_append (output, ",\n ");
+
+ g_string_append_printf (output,
+ "{ \"name\": \"%s\",\n"
+ " \"description\": \"%s\"",
+ event->name, escaped_description);
+ if (is_statistic)
+ g_string_append (output, ",\n \"statistic\": true");
+
+ g_string_append (output, " }");
+
+ if (escaped_description != event->description)
+ g_free (escaped_description);
+ }
+
+ g_string_append (output, " ]");
+
+ return write_string (out, g_string_free (output, FALSE), error);
+}
+
+typedef struct {
+ GOutputStream *out;
+ GError *error;
+ gboolean first;
+} ReplayToJsonClosure;
+
+static void
+replay_to_json (gint64 time,
+ const char *name,
+ const char *signature,
+ GValue *arg,
+ gpointer user_data)
+{
+ ReplayToJsonClosure *closure = user_data;
+ char *event_str;
+
+ if (closure->error != NULL)
+ return;
+
+ if (!closure->first)
+ {
+ if (!write_string (closure->out, ",\n ", &closure->error))
+ return;
+ }
+
+ closure->first = FALSE;
+
+ if (strcmp (signature, "") == 0)
+ {
+ event_str = g_strdup_printf ("[%" G_GINT64_FORMAT ", \"%s\"]", time, name);
+ }
+ else if (strcmp (signature, "i") == 0)
+ {
+ event_str = g_strdup_printf ("[%" G_GINT64_FORMAT ", \"%s\", %i]",
+ time,
+ name,
+ g_value_get_int (arg));
+ }
+ else if (strcmp (signature, "x") == 0)
+ {
+ event_str = g_strdup_printf ("[%" G_GINT64_FORMAT ", \"%s\", %"G_GINT64_FORMAT "]",
+ time,
+ name,
+ g_value_get_int64 (arg));
+ }
+ else if (strcmp (signature, "s") == 0)
+ {
+ const char *arg_str = g_value_get_string (arg);
+ char *escaped = escape_quotes (arg_str);
+
+ event_str = g_strdup_printf ("[%" G_GINT64_FORMAT ", \"%s\", \"%s\"]",
+ time,
+ name,
+ g_value_get_string (arg));
+
+ if (escaped != arg_str)
+ g_free (escaped);
+ }
+ else
+ {
+ g_assert_not_reached ();
+ }
+
+ if (!write_string (closure->out, event_str, &closure->error))
+ return;
+}
+
+/**
+ * shell_perf_log_dump_log:
+ * @perf_log: a #ShellPerfLog
+ * @out: output stream into which to write the event log
+ * @error: location to store #GError, or %NULL
+ *
+ * Writes the performance event log, formatted as JSON, to the specified
+ * output stream. For performance reasons, the output stream passed
+ * in should generally be a buffered (or memory) output stream, since
+ * it will be written to in small pieces. The JSON output is an array
+ * with the elements of the array also being arrays, of the form
+ * '[' <time>, <event name> [, <event_arg>... ] ']'.
+ *
+ * Return value: %TRUE if the dump succeeded. %FALSE if an IO error occurred
+ */
+gboolean
+shell_perf_log_dump_log (ShellPerfLog *perf_log,
+ GOutputStream *out,
+ GError **error)
+{
+ ReplayToJsonClosure closure;
+
+ closure.out = out;
+ closure.error = NULL;
+ closure.first = TRUE;
+
+ if (!write_string (out, "[ ", &closure.error))
+ return FALSE;
+
+ shell_perf_log_replay (perf_log, replay_to_json, &closure);
+
+ if (closure.error != NULL)
+ {
+ g_propagate_error (error, closure.error);
+ return FALSE;
+ }
+
+ if (!write_string (out, " ]", &closure.error))
+ return FALSE;
+
+ return TRUE;
+}