Merge pull request #1785 from libgit2/cmn/odb-hash-frontend

odb: move hashing to the frontend for streaming

1 files changed, 29 insertions, 2 deletions

diff --git a/include/git2/odb_backend.h b/include/git2/odb_backend.h
index af1e3e5b9..dca499583 100644
--- a/include/git2/odb_backend.h
+++ b/include/git2/odb_backend.h
@@ -65,14 +65,41 @@ typedef enum {
 	GIT_STREAM_RW = (GIT_STREAM_RDONLY | GIT_STREAM_WRONLY),
 } git_odb_stream_t;
 
-/** A stream to read/write from a backend */
+typedef struct git_hash_ctx git_hash_ctx;
+
+/**
+ * A stream to read/write from a backend.
+ *
+ * This represents a stream of data being written to or read from a
+ * backend. When writing, the frontend functions take care of
+ * calculating the object's id and all `finalize_write` needs to do is
+ * store the object with the id it is passed.
+ */
 struct git_odb_stream {
 	git_odb_backend *backend;
 	unsigned int mode;
+	git_hash_ctx *hash_ctx;
 
+	/**
+	 * Write at most `len` bytes into `buffer` and advance the
+	 * stream.
+	 */
 	int (*read)(git_odb_stream *stream, char *buffer, size_t len);
+
+	/**
+	 * Write `len` bytes from `buffer` into the stream.
+	 */
 	int (*write)(git_odb_stream *stream, const char *buffer, size_t len);
-	int (*finalize_write)(git_oid *oid_p, git_odb_stream *stream);
+
+	/**
+	 * Store the contents of the stream as an object with the id
+	 * specified in `oid`.
+	 */
+	int (*finalize_write)(git_odb_stream *stream, const git_oid *oid);
+
+	/**
+	 * Free the stream's memory.
+	 */
 	void (*free)(git_odb_stream *stream);
 };