capture: add simple mark support

The goal here is to have an API that allows us to record things like
frame timing data. We might iterate on this API a bit, but this gets us
started.

A SpCaptureMark with a zero duration should be treated like an epoch mark
once a visualizer is created. SpCaptureMark with a non-zero duration should
be treated like a begin/end of operation. This may be useful in generating
something like a flame graph.

lib/capture/sp-capture-cursor.c

@@ -99,6 +99,10 @@ sp_capture_cursor_foreach (SpCaptureCursor         *self,
           delegate = READ_DELEGATE (sp_capture_reader_read_map);
           break;
 
+        case SP_CAPTURE_FRAME_MARK:
+          delegate = READ_DELEGATE (sp_capture_reader_read_mark);
+          break;
+
         case SP_CAPTURE_FRAME_PROCESS:
           delegate = READ_DELEGATE (sp_capture_reader_read_process);
           break;

lib/capture/sp-capture-reader.c

@@ -198,6 +198,17 @@ sp_capture_reader_bswap_map (SpCaptureReader *self,
     }
 }
 
+static inline void
+sp_capture_reader_bswap_mark (SpCaptureReader *self,
+                              SpCaptureMark   *mark)
+{
+  g_assert (self != NULL);
+  g_assert (mark != NULL);
+
+  if (G_UNLIKELY (self->endian != G_BYTE_ORDER))
+    mark->duration = GUINT64_SWAP_LE_BE (mark->duration);
+}
+
 static inline void
 sp_capture_reader_bswap_jitmap (SpCaptureReader *self,
                                 SpCaptureJitmap *jitmap)
@@ -426,6 +437,47 @@ sp_capture_reader_read_map (SpCaptureReader *self)
   return map;
 }
 
+const SpCaptureMark *
+sp_capture_reader_read_mark (SpCaptureReader *self)
+{
+  SpCaptureMark *mark;
+
+  g_assert (self != NULL);
+  g_assert ((self->pos % SP_CAPTURE_ALIGN) == 0);
+  g_assert (self->pos <= self->bufsz);
+
+  if (!sp_capture_reader_ensure_space_for (self, sizeof *mark))
+    return NULL;
+
+  mark = (SpCaptureMark *)(gpointer)&self->buf[self->pos];
+
+  sp_capture_reader_bswap_frame (self, &mark->frame);
+
+  if (mark->frame.type != SP_CAPTURE_FRAME_MARK)
+    return NULL;
+
+  if (mark->frame.len < (sizeof *mark + 1))
+    return NULL;
+
+  if (!sp_capture_reader_ensure_space_for (self, mark->frame.len))
+    return NULL;
+
+  mark = (SpCaptureMark *)(gpointer)&self->buf[self->pos];
+
+  sp_capture_reader_bswap_mark (self, mark);
+
+  self->pos += mark->frame.len;
+
+  if ((self->pos % SP_CAPTURE_ALIGN) != 0)
+    return NULL;
+
+  /* Ensure trailing \0 in name and message */
+  mark->name[sizeof mark->name - 1] = 0;
+  self->buf[self->pos + mark->frame.len - 1] = 0;
+
+  return mark;
+}
+
 const SpCaptureProcess *
 sp_capture_reader_read_process (SpCaptureReader *self)
 {

lib/capture/sp-capture-reader.h

@@ -42,6 +42,7 @@ gboolean                           sp_capture_reader_peek_type           (SpCapt
 gboolean                           sp_capture_reader_peek_frame          (SpCaptureReader     *self,
                                                                           SpCaptureFrame      *frame);
 const SpCaptureMap                *sp_capture_reader_read_map            (SpCaptureReader     *self);
+const SpCaptureMark               *sp_capture_reader_read_mark           (SpCaptureReader     *self);
 const SpCaptureExit               *sp_capture_reader_read_exit           (SpCaptureReader     *self);
 const SpCaptureFork               *sp_capture_reader_read_fork           (SpCaptureReader     *self);
 const SpCaptureTimestamp          *sp_capture_reader_read_timestamp      (SpCaptureReader     *self);

lib/capture/sp-capture-types.h

@@ -68,6 +68,7 @@ typedef enum
   SP_CAPTURE_FRAME_JITMAP    = 7,
   SP_CAPTURE_FRAME_CTRDEF    = 8,
   SP_CAPTURE_FRAME_CTRSET    = 9,
+  SP_CAPTURE_FRAME_MARK      = 10,
 } SpCaptureFrameType;
 
 #pragma pack(push, 1)
@@ -179,6 +180,14 @@ typedef struct
   SpCaptureCounterValues values[0];
 } SpCaptureFrameCounterSet;
 
+typedef struct
+{
+  SpCaptureFrame frame;
+  gint64         duration;
+  gchar          name[32];
+  gchar          message[0];
+} SpCaptureMark;
+
 #pragma pack(pop)
 
 G_STATIC_ASSERT (sizeof (SpCaptureFileHeader) == 256);
@@ -194,6 +203,7 @@ G_STATIC_ASSERT (sizeof (SpCaptureCounter) == 128);
 G_STATIC_ASSERT (sizeof (SpCaptureCounterValues) == 96);
 G_STATIC_ASSERT (sizeof (SpCaptureFrameCounterDefine) == 32);
 G_STATIC_ASSERT (sizeof (SpCaptureFrameCounterSet) == 32);
+G_STATIC_ASSERT (sizeof (SpCaptureMark) == 64);
 
 static inline gint
 sp_capture_address_compare (SpCaptureAddress a,

lib/capture/sp-capture-writer.c

@@ -536,6 +536,45 @@ sp_capture_writer_add_map (SpCaptureWriter *self,
   return TRUE;
 }
 
+gboolean
+sp_capture_writer_add_mark (SpCaptureWriter *self,
+                            gint64           time,
+                            gint             cpu,
+                            GPid             pid,
+                            guint64          duration,
+                            const gchar     *name,
+                            const gchar     *message)
+{
+  SpCaptureMark *ev;
+  gsize message_len;
+  gsize len;
+
+  g_assert (self != NULL);
+  g_assert (name != NULL);
+
+  if (message == NULL)
+    message = "";
+  message_len = strlen (message) + 1;
+
+  len = sizeof *ev + message_len;
+  ev = (SpCaptureMark *)sp_capture_writer_allocate (self, &len);
+  if (!ev)
+    return FALSE;
+
+  sp_capture_writer_frame_init (&ev->frame,
+                                len,
+                                cpu,
+                                pid,
+                                time,
+                                SP_CAPTURE_FRAME_MARK);
+
+  ev->duration = duration;
+  memcpy (ev->name, name, sizeof ev->name);
+  memcpy (ev->message, message, message_len);
+
+  return TRUE;
+}
+
 SpCaptureAddress
 sp_capture_writer_add_jitmap (SpCaptureWriter *self,
                               const gchar     *name)

lib/capture/sp-capture-writer.h

@@ -55,6 +55,13 @@ gboolean            sp_capture_writer_add_map         (SpCaptureWriter         *
                                                        guint64                  offset,
                                                        guint64                  inode,
                                                        const gchar             *filename);
+gboolean            sp_capture_writer_add_mark        (SpCaptureWriter         *self,
+                                                       gint64                   time,
+                                                       gint                     cpu,
+                                                       GPid                     pid,
+                                                       guint64                  duration,
+                                                       const gchar             *name,
+                                                       const gchar             *message);
 guint64             sp_capture_writer_add_jitmap      (SpCaptureWriter         *self,
                                                        const gchar             *name);
 gboolean            sp_capture_writer_add_process     (SpCaptureWriter         *self,