libsysprof-capture: add metadata frame type

This will allow sources and aids to discover information about what was
done between capture loading and saving.

src/libsysprof-capture/sysprof-capture-cursor.c

@@ -159,6 +159,10 @@ sysprof_capture_cursor_foreach (SysprofCaptureCursor         *self,
           delegate = READ_DELEGATE (sysprof_capture_reader_read_counter_set);
           break;
 
+        case SYSPROF_CAPTURE_FRAME_METADATA:
+          delegate = READ_DELEGATE (sysprof_capture_reader_read_metadata);
+          break;
+
         default:
           if (!sysprof_capture_reader_skip (self->reader))
             return;

src/libsysprof-capture/sysprof-capture-reader.c

@@ -532,6 +532,45 @@ sysprof_capture_reader_read_mark (SysprofCaptureReader *self)
   return mark;
 }
 
+const SysprofCaptureMetadata *
+sysprof_capture_reader_read_metadata (SysprofCaptureReader *self)
+{
+  SysprofCaptureMetadata *metadata;
+
+  g_assert (self != NULL);
+  g_assert ((self->pos % SYSPROF_CAPTURE_ALIGN) == 0);
+  g_assert (self->pos <= self->bufsz);
+
+  if (!sysprof_capture_reader_ensure_space_for (self, sizeof *metadata))
+    return NULL;
+
+  metadata = (SysprofCaptureMetadata *)(gpointer)&self->buf[self->pos];
+
+  sysprof_capture_reader_bswap_frame (self, &metadata->frame);
+
+  if (metadata->frame.type != SYSPROF_CAPTURE_FRAME_METADATA)
+    return NULL;
+
+  if (metadata->frame.len < (sizeof *metadata + 1))
+    return NULL;
+
+  if (!sysprof_capture_reader_ensure_space_for (self, metadata->frame.len))
+    return NULL;
+
+  metadata = (SysprofCaptureMetadata *)(gpointer)&self->buf[self->pos];
+
+  self->pos += metadata->frame.len;
+
+  if ((self->pos % SYSPROF_CAPTURE_ALIGN) != 0)
+    return NULL;
+
+  /* Ensure trailing \0 in .id and .metadata */
+  metadata->id[sizeof metadata->id - 1] = 0;
+  self->buf[self->pos + metadata->frame.len - 1] = 0;
+
+  return metadata;
+}
+
 const SysprofCaptureProcess *
 sysprof_capture_reader_read_process (SysprofCaptureReader *self)
 {

src/libsysprof-capture/sysprof-capture-reader.h

@@ -60,6 +60,8 @@ const SysprofCaptureMap                *sysprof_capture_reader_read_map
 SYSPROF_AVAILABLE_IN_ALL
 const SysprofCaptureMark               *sysprof_capture_reader_read_mark           (SysprofCaptureReader     *self);
 SYSPROF_AVAILABLE_IN_ALL
+const SysprofCaptureMetadata           *sysprof_capture_reader_read_metadata       (SysprofCaptureReader     *self);
+SYSPROF_AVAILABLE_IN_ALL
 const SysprofCaptureExit               *sysprof_capture_reader_read_exit           (SysprofCaptureReader     *self);
 SYSPROF_AVAILABLE_IN_ALL
 const SysprofCaptureFork               *sysprof_capture_reader_read_fork           (SysprofCaptureReader     *self);

src/libsysprof-capture/sysprof-capture-types.h

@@ -89,6 +89,7 @@ typedef enum
   SYSPROF_CAPTURE_FRAME_CTRDEF    = 8,
   SYSPROF_CAPTURE_FRAME_CTRSET    = 9,
   SYSPROF_CAPTURE_FRAME_MARK      = 10,
+  SYSPROF_CAPTURE_FRAME_METADATA  = 11,
 } SysprofCaptureFrameType;
 
 SYSPROF_ALIGNED_BEGIN(1)
@@ -239,6 +240,15 @@ typedef struct
 } SysprofCaptureMark
 SYSPROF_ALIGNED_END(1);
 
+SYSPROF_ALIGNED_BEGIN(1)
+typedef struct
+{
+  SysprofCaptureFrame frame;
+  gchar               id[40];
+  gchar               metadata[0];
+} SysprofCaptureMetadata
+SYSPROF_ALIGNED_END(1);
+
 G_STATIC_ASSERT (sizeof (SysprofCaptureFileHeader) == 256);
 G_STATIC_ASSERT (sizeof (SysprofCaptureFrame) == 24);
 G_STATIC_ASSERT (sizeof (SysprofCaptureMap) == 56);
@@ -253,6 +263,7 @@ G_STATIC_ASSERT (sizeof (SysprofCaptureCounterValues) == 96);
 G_STATIC_ASSERT (sizeof (SysprofCaptureFrameCounterDefine) == 32);
 G_STATIC_ASSERT (sizeof (SysprofCaptureFrameCounterSet) == 32);
 G_STATIC_ASSERT (sizeof (SysprofCaptureMark) == 96);
+G_STATIC_ASSERT (sizeof (SysprofCaptureMetadata) == 64);
 
 static inline gint
 sysprof_capture_address_compare (SysprofCaptureAddress a,

src/libsysprof-capture/sysprof-capture-writer.c

@@ -587,6 +587,51 @@ sysprof_capture_writer_add_mark (SysprofCaptureWriter *self,
   return TRUE;
 }
 
+gboolean
+sysprof_capture_writer_add_metadata (SysprofCaptureWriter *self,
+                                     gint64                time,
+                                     gint                  cpu,
+                                     gint32                pid,
+                                     const gchar          *id,
+                                     const gchar          *metadata,
+                                     gssize                metadata_len)
+{
+  SysprofCaptureMetadata *ev;
+  gsize len;
+
+  g_assert (self != NULL);
+  g_assert (id != NULL);
+
+  if (metadata == NULL)
+    {
+      metadata = "";
+      len = 0;
+    }
+
+  if (metadata_len < 0)
+    metadata_len = strlen (metadata);
+
+  len = sizeof *ev + metadata_len + 1;
+  ev = (SysprofCaptureMetadata *)sysprof_capture_writer_allocate (self, &len);
+  if (!ev)
+    return FALSE;
+
+  sysprof_capture_writer_frame_init (&ev->frame,
+                                     len,
+                                     cpu,
+                                     pid,
+                                     time,
+                                     SYSPROF_CAPTURE_FRAME_METADATA);
+
+  g_strlcpy (ev->id, id, sizeof ev->id);
+  memcpy (ev->metadata, metadata, metadata_len);
+  ev->metadata[metadata_len] = 0;
+
+  self->stat.frame_count[SYSPROF_CAPTURE_FRAME_METADATA]++;
+
+  return TRUE;
+}
+
 SysprofCaptureAddress
 sysprof_capture_writer_add_jitmap (SysprofCaptureWriter *self,
                                    const gchar          *name)

src/libsysprof-capture/sysprof-capture-writer.h

@@ -62,6 +62,14 @@ gboolean              sysprof_capture_writer_add_mark        (SysprofCaptureWrit
                                                               const gchar                       *name,
                                                               const gchar                       *message);
 SYSPROF_AVAILABLE_IN_ALL
+gboolean              sysprof_capture_writer_add_metadata    (SysprofCaptureWriter              *self,
+                                                              gint64                             time,
+                                                              gint                               cpu,
+                                                              gint32                             pid,
+                                                              const gchar                       *id,
+                                                              const gchar                       *metadata,
+                                                              gssize                             metadata_len);
+SYSPROF_AVAILABLE_IN_ALL
 guint64               sysprof_capture_writer_add_jitmap      (SysprofCaptureWriter              *self,
                                                               const gchar                       *name);
 SYSPROF_AVAILABLE_IN_ALL