Merge pull request #4450 from libgit2/ethomson/odb_loose_readstream

Streaming read support for the loose ODB backend

include/git2/odb.h

@@ -357,11 +357,18 @@ GIT_EXTERN(void) git_odb_stream_free(git_odb_stream *stream);
  * @see git_odb_stream
  *
  * @param out pointer where to store the stream
+ * @param len pointer where to store the length of the object
+ * @param type pointer where to store the type of the object
  * @param db object database where the stream will read from
  * @param oid oid of the object the stream will read from
  * @return 0 if the stream was created; error code otherwise
  */
-GIT_EXTERN(int) git_odb_open_rstream(git_odb_stream **out, git_odb *db, const git_oid *oid);
+GIT_EXTERN(int) git_odb_open_rstream(
+	git_odb_stream **out,
+	size_t *len,
+	git_otype *type,
+	git_odb *db,
+	const git_oid *oid);
 
 /**
  * Open a stream for writing a pack file to the ODB.

include/git2/sys/odb_backend.h

@@ -56,7 +56,8 @@ struct git_odb_backend {
 		git_odb_stream **, git_odb_backend *, git_off_t, git_otype);
 
 	int (* readstream)(
-		git_odb_stream **, git_odb_backend *, const git_oid *);
+		git_odb_stream **, size_t *, git_otype *,
+		git_odb_backend *, const git_oid *);
 
 	int (* exists)(
 		git_odb_backend *, const git_oid *);

src/odb.c

@@ -1396,7 +1396,12 @@ void git_odb_stream_free(git_odb_stream *stream)
 	stream->free(stream);
 }
 
-int git_odb_open_rstream(git_odb_stream **stream, git_odb *db, const git_oid *oid)
+int git_odb_open_rstream(
+	git_odb_stream **stream,
+	size_t *len,
+	git_otype *type,
+	git_odb *db,
+	const git_oid *oid)
 {
 	size_t i, reads = 0;
 	int error = GIT_ERROR;
@@ -1409,7 +1414,7 @@ int git_odb_open_rstream(git_odb_stream **stream, git_odb *db, const git_oid *oi
 
 		if (b->readstream != NULL) {
 			++reads;
-			error = b->readstream(stream, b, oid);
+			error = b->readstream(stream, len, type, b, oid);
 		}
 	}
 

src/zstream.c

@@ -87,58 +87,71 @@ size_t git_zstream_suggest_output_len(git_zstream *zstream)
 		return ZSTREAM_BUFFER_MIN_EXTRA;
 }
 
-int git_zstream_get_output(void *out, size_t *out_len, git_zstream *zstream)
+int git_zstream_get_output_chunk(
+	void *out, size_t *out_len, git_zstream *zstream)
 {
-	int zflush = Z_FINISH;
-	size_t out_remain = *out_len;
-
-	if (zstream->in_len && zstream->zerr == Z_STREAM_END) {
-		giterr_set(GITERR_ZLIB, "zlib input had trailing garbage");
-		return -1;
-	}
-
-	while (out_remain > 0 && zstream->zerr != Z_STREAM_END) {
-		size_t out_queued, in_queued, out_used, in_used;
+	size_t in_queued, in_used, out_queued;
 
-		/* set up in data */
+	/* set up input data */
 	zstream->z.next_in = (Bytef *)zstream->in;
-		zstream->z.avail_in = (uInt)zstream->in_len;
 
-		if ((size_t)zstream->z.avail_in != zstream->in_len) {
+	/* feed as much data to zlib as it can consume, at most UINT_MAX */
+	if (zstream->in_len > UINT_MAX) {
 		zstream->z.avail_in = UINT_MAX;
-			zflush = Z_NO_FLUSH;
+		zstream->flush = Z_NO_FLUSH;
 	} else {
-			zflush = Z_FINISH;
+		zstream->z.avail_in = (uInt)zstream->in_len;
+		zstream->flush = Z_FINISH;
 	}
 	in_queued = (size_t)zstream->z.avail_in;
 
-		/* set up out data */
+	/* set up output data */
 	zstream->z.next_out = out;
-		zstream->z.avail_out = (uInt)out_remain;
-		if ((size_t)zstream->z.avail_out != out_remain)
+	zstream->z.avail_out = (uInt)*out_len;
+
+	if ((size_t)zstream->z.avail_out != *out_len)
 		zstream->z.avail_out = UINT_MAX;
 	out_queued = (size_t)zstream->z.avail_out;
 
 	/* compress next chunk */
 	if (zstream->type == GIT_ZSTREAM_INFLATE)
-			zstream->zerr = inflate(&zstream->z, zflush);
+		zstream->zerr = inflate(&zstream->z, zstream->flush);
 	else
-			zstream->zerr = deflate(&zstream->z, zflush);
+		zstream->zerr = deflate(&zstream->z, zstream->flush);
 
 	if (zstream_seterr(zstream))
 		return -1;
 
-		out_used = (out_queued - zstream->z.avail_out);
-		out_remain -= out_used;
-		out = ((char *)out) + out_used;
-
 	in_used = (in_queued - zstream->z.avail_in);
 	zstream->in_len -= in_used;
 	zstream->in += in_used;
+
+	*out_len = (out_queued - zstream->z.avail_out);
+
+	return 0;
+}
+
+int git_zstream_get_output(void *out, size_t *out_len, git_zstream *zstream)
+{
+	size_t out_remain = *out_len;
+
+	if (zstream->in_len && zstream->zerr == Z_STREAM_END) {
+		giterr_set(GITERR_ZLIB, "zlib input had trailing garbage");
+		return -1;
+	}
+
+	while (out_remain > 0 && zstream->zerr != Z_STREAM_END) {
+		size_t out_written = out_remain;
+
+		if (git_zstream_get_output_chunk(out, &out_written, zstream) < 0)
+			return -1;
+
+		out_remain -= out_written;
+		out = ((char *)out) + out_written;
 	}
 
 	/* either we finished the input or we did not flush the data */
-	assert(zstream->in_len > 0 || zflush == Z_FINISH);
+	assert(zstream->in_len > 0 || zstream->flush == Z_FINISH);
 
 	/* set out_size to number of bytes actually written to output */
 	*out_len = *out_len - out_remain;

src/zstream.h

@@ -23,6 +23,7 @@ typedef struct {
 	git_zstream_t type;
 	const char *in;
 	size_t in_len;
+	int flush;
 	int zerr;
 } git_zstream;
 
@@ -35,6 +36,11 @@ int git_zstream_set_input(git_zstream *zstream, const void *in, size_t in_len);
 
 size_t git_zstream_suggest_output_len(git_zstream *zstream);
 
+/* get as much output as is available in the input buffer */
+int git_zstream_get_output_chunk(
+	void *out, size_t *out_len, git_zstream *zstream);
+
+/* get all the output from the entire input buffer */
 int git_zstream_get_output(void *out, size_t *out_len, git_zstream *zstream);
 
 bool git_zstream_done(git_zstream *zstream);

tests/odb/largefiles.c

 #include "clar_libgit2.h"
 #include "git2/odb_backend.h"
+#include "hash.h"
+#include "odb.h"
+
+#define LARGEFILE_SIZE 5368709122
 
 static git_repository *repo;
 static git_odb *odb;
@@ -25,7 +29,7 @@ static void writefile(git_oid *oid)
 	for (i = 0; i < 3041; i++)
 		cl_git_pass(git_buf_puts(&buf, "Hello, world.\n"));
 
-	cl_git_pass(git_odb_open_wstream(&stream, odb, 5368709122, GIT_OBJ_BLOB));
+	cl_git_pass(git_odb_open_wstream(&stream, odb, LARGEFILE_SIZE, GIT_OBJ_BLOB));
 	for (i = 0; i < 126103; i++)
 		cl_git_pass(git_odb_stream_write(stream, buf.ptr, buf.size));
 
@@ -63,6 +67,10 @@ void test_odb_largefiles__streamwrite(void)
 {
 	git_oid expected, oid;
 
+#ifndef GIT_ARCH_64
+	cl_skip();
+#endif
+
 	if (!cl_is_env_set("GITTEST_INVASIVE_FS_SIZE") ||
 		!cl_is_env_set("GITTEST_SLOW"))
 		cl_skip();
@@ -73,6 +81,52 @@ void test_odb_largefiles__streamwrite(void)
 	cl_assert_equal_oid(&expected, &oid);
 }
 
+void test_odb_largefiles__streamread(void)
+{
+	git_oid oid, read_oid;
+	git_odb_stream *stream;
+	char buf[10240];
+	char hdr[64];
+	size_t len, total = 0;
+	git_hash_ctx hash;
+	git_otype type;
+	int hdr_len, ret;
+
+#ifndef GIT_ARCH_64
+	cl_skip();
+#endif
+
+	if (!cl_is_env_set("GITTEST_INVASIVE_FS_SIZE") ||
+		!cl_is_env_set("GITTEST_SLOW"))
+		cl_skip();
+
+	writefile(&oid);
+
+	cl_git_pass(git_odb_open_rstream(&stream, &len, &type, odb, &oid));
+
+	cl_assert_equal_sz(LARGEFILE_SIZE, len);
+	cl_assert_equal_i(GIT_OBJ_BLOB, type);
+
+	cl_git_pass(git_hash_ctx_init(&hash));
+	hdr_len = git_odb__format_object_header(hdr, sizeof(hdr), len, type);
+
+	cl_git_pass(git_hash_update(&hash, hdr, hdr_len));
+
+	while ((ret = git_odb_stream_read(stream, buf, 10240)) > 0) {
+		cl_git_pass(git_hash_update(&hash, buf, ret));
+		total += ret;
+	}
+
+	cl_assert_equal_sz(LARGEFILE_SIZE, total);
+
+	git_hash_final(&read_oid, &hash);
+
+	cl_assert_equal_oid(&oid, &read_oid);
+
+	git_hash_ctx_cleanup(&hash);
+	git_odb_stream_free(stream);
+}
+
 void test_odb_largefiles__read_into_memory(void)
 {
 	git_oid oid;
@@ -112,3 +166,24 @@ void test_odb_largefiles__read_into_memory_rejected_on_32bit(void)
 
 	git_odb_object_free(obj);
 }
+
+void test_odb_largefiles__read_header(void)
+{
+	git_oid oid;
+	size_t len;
+	git_otype type;
+
+#ifndef GIT_ARCH_64
+	cl_skip();
+#endif
+
+	if (!cl_is_env_set("GITTEST_INVASIVE_FS_SIZE") ||
+		!cl_is_env_set("GITTEST_SLOW"))
+		cl_skip();
+
+	writefile(&oid);
+	cl_git_pass(git_odb_read_header(&len, &type, odb, &oid));
+
+	cl_assert_equal_sz(LARGEFILE_SIZE, len);
+	cl_assert_equal_i(GIT_OBJ_BLOB, type);
+}

tests/odb/loose.c

@@ -55,6 +55,63 @@ static void test_read_object(object_data *data)
 	git_odb_free(odb);
 }
 
+static void test_read_header(object_data *data)
+{
+	git_oid id;
+	git_odb *odb;
+	size_t len;
+	git_otype type;
+
+	write_object_files(data);
+
+	cl_git_pass(git_odb_open(&odb, "test-objects"));
+	cl_git_pass(git_oid_fromstr(&id, data->id));
+	cl_git_pass(git_odb_read_header(&len, &type, odb, &id));
+
+	cl_assert_equal_sz(data->dlen, len);
+	cl_assert_equal_i(git_object_string2type(data->type), type);
+
+	git_odb_free(odb);
+}
+
+static void test_readstream_object(object_data *data, size_t blocksize)
+{
+	git_oid id;
+	git_odb *odb;
+	git_odb_stream *stream;
+	git_rawobj tmp;
+	char buf[2048], *ptr = buf;
+	size_t remain;
+	int ret;
+
+	write_object_files(data);
+
+	cl_git_pass(git_odb_open(&odb, "test-objects"));
+	cl_git_pass(git_oid_fromstr(&id, data->id));
+	cl_git_pass(git_odb_open_rstream(&stream, &tmp.len, &tmp.type, odb, &id));
+
+	remain = tmp.len;
+
+	while (remain) {
+		cl_assert((ret = git_odb_stream_read(stream, ptr, blocksize)) >= 0);
+		if (ret == 0)
+			break;
+
+		cl_assert(remain >= (size_t)ret);
+		remain -= ret;
+		ptr += ret;
+	}
+
+	cl_assert(remain == 0);
+
+	tmp.data = buf;
+
+	cmp_objects(&tmp, data);
+
+	git_odb_stream_free(stream);
+	git_odb_free(odb);
+}
+
 void test_odb_loose__initialize(void)
 {
 	p_fsync__cnt = 0;
@@ -103,6 +160,33 @@ void test_odb_loose__simple_reads(void)
 	test_read_object(&some);
 }
 
+void test_odb_loose__streaming_reads(void)
+{
+	size_t blocksizes[] = { 1, 2, 4, 16, 99, 1024, 123456789 };
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(blocksizes); i++) {
+		test_readstream_object(&commit, blocksizes[i]);
+		test_readstream_object(&tree, blocksizes[i]);
+		test_readstream_object(&tag, blocksizes[i]);
+		test_readstream_object(&zero, blocksizes[i]);
+		test_readstream_object(&one, blocksizes[i]);
+		test_readstream_object(&two, blocksizes[i]);
+		test_readstream_object(&some, blocksizes[i]);
+	}
+}
+
+void test_odb_loose__read_header(void)
+{
+	test_read_header(&commit);
+	test_read_header(&tree);
+	test_read_header(&tag);
+	test_read_header(&zero);
+	test_read_header(&one);
+	test_read_header(&two);
+	test_read_header(&some);
+}
+
 void test_write_object_permission(
 	mode_t dir_mode, mode_t file_mode,
 	mode_t expected_dir_mode, mode_t expected_file_mode)