Camera: Add clone buffer, make type names public

Clone metadata buffer allows for straightforward duplication of
existing buffers; type names are useful for debugging code.

Bug: 6243944
Change-Id: Ibf70f4e3bcf49d6c772bba18a577e2673f2b9213

2 files changed, 33 insertions, 3 deletions

diff --git a/camera/include/system/camera_metadata.h b/camera/include/system/camera_metadata.h
index d5eac654..62963a2c 100644
--- a/camera/include/system/camera_metadata.h
+++ b/camera/include/system/camera_metadata.h
@@ -96,7 +96,13 @@ typedef struct camera_metadata_entry {
  * Size in bytes of each entry type
  */
 ANDROID_API
-extern size_t camera_metadata_type_size[NUM_TYPES];
+extern const size_t camera_metadata_type_size[NUM_TYPES];
+
+/**
+ * Human-readable name of each entry type
+ */
+ANDROID_API
+extern const char* camera_metadata_type_names[NUM_TYPES];
 
 /**
  * Main definitions for the metadata entry and array structures
@@ -237,6 +243,15 @@ ANDROID_API
 int append_camera_metadata(camera_metadata_t *dst, const camera_metadata_t *src);
 
 /**
+ * Clone an existing metadata buffer, compacting along the way. This is
+ * equivalent to allocating a new buffer of the minimum needed size, then
+ * appending the buffer to be cloned into the new buffer. The resulting buffer
+ * can be freed with free_camera_metadata(). Returns NULL if cloning failed.
+ */
+ANDROID_API
+camera_metadata_t *clone_camera_metadata(camera_metadata_t *src);
+
+/**
  * Calculate the number of bytes of extra data a given metadata entry will take
  * up. That is, if entry of 'type' with a payload of 'data_count' values is
  * added, how much will the value returned by get_camera_metadata_data_count()
diff --git a/camera/src/camera_metadata.c b/camera/src/camera_metadata.c
index 7c535d92..ee00ee60 100644
--- a/camera/src/camera_metadata.c
+++ b/camera/src/camera_metadata.c
@@ -103,7 +103,7 @@ typedef struct tag_info {
 
 #include "camera_metadata_tag_info.c"
 
-size_t camera_metadata_type_size[NUM_TYPES] = {
+const size_t camera_metadata_type_size[NUM_TYPES] = {
     [TYPE_BYTE]     = sizeof(uint8_t),
     [TYPE_INT32]    = sizeof(int32_t),
     [TYPE_FLOAT]    = sizeof(float),
@@ -112,7 +112,7 @@ size_t camera_metadata_type_size[NUM_TYPES] = {
     [TYPE_RATIONAL] = sizeof(camera_metadata_rational_t)
 };
 
-char *camera_metadata_type_names[NUM_TYPES] = {
+const char *camera_metadata_type_names[NUM_TYPES] = {
     [TYPE_BYTE]     = "byte",
     [TYPE_INT32]    = "int32",
     [TYPE_FLOAT]    = "float",
@@ -280,6 +280,21 @@ int append_camera_metadata(camera_metadata_t *dst,
     return OK;
 }
 
+camera_metadata_t *clone_camera_metadata(camera_metadata_t *src) {
+    int res;
+    camera_metadata_t *clone = allocate_camera_metadata(
+        get_camera_metadata_entry_count(src),
+        get_camera_metadata_data_count(src));
+    if (clone != NULL) {
+        res = append_camera_metadata(clone, src);
+        if (res != OK) {
+            free_camera_metadata(clone);
+            clone = NULL;
+        }
+    }
+    return clone;
+}
+
 size_t calculate_camera_metadata_entry_data_size(uint8_t type,
         size_t data_count) {
     if (type >= NUM_TYPES) return 0;