binary diff: further updates.
This updates the user interface and generated diff data format.
* "diff --binary" is used to signal that we want an e-mailable
binary patch. It implies --full-index and -p.
* "apply --allow-binary-replacement" acquired a short synonym
"apply --binary".
* After the "GIT binary patch\n" header line there is a token
to record which binary patch mechanism was used, so that we
can extend it later. Currently there are two mechanisms
defined: "literal" and "delta". The former records the
deflated postimage and the latter records the deflated delta
from the preimage to postimage.
For purely implementation convenience, I added the deflated
length after these "literal/delta" tokens (otherwise the
decoding side needs to guess and reallocate the buffer while
inflating). Improvement patches are very welcomed.
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/apply.c b/apply.c
index e37c4eb..1b93aab 100644
--- a/apply.c
+++ b/apply.c
@@ -114,6 +114,9 @@
char *new_name, *old_name, *def_name;
unsigned int old_mode, new_mode;
int is_rename, is_copy, is_new, is_delete, is_binary;
+#define BINARY_DELTA_DEFLATED 1
+#define BINARY_LITERAL_DEFLATED 2
+ unsigned long deflate_origlen;
int lines_added, lines_deleted;
int score;
struct fragment *fragments;
@@ -969,9 +972,11 @@
static int parse_binary(char *buffer, unsigned long size, struct patch *patch)
{
- /* We have read "GIT binary patch\n"; what follows is a
- * sequence of 'length-byte' followed by base-85 encoded
- * delta data.
+ /* We have read "GIT binary patch\n"; what follows is a line
+ * that says the patch method (currently, either "deflated
+ * literal" or "deflated delta") and the length of data before
+ * deflating; a sequence of 'length-byte' followed by base-85
+ * encoded data follows.
*
* Each 5-byte sequence of base-85 encodes up to 4 bytes,
* and we would limit the patch line to 66 characters,
@@ -982,11 +987,27 @@
*/
int llen, used;
struct fragment *fragment;
- char *delta = NULL;
+ char *data = NULL;
- patch->is_binary = 1;
patch->fragments = fragment = xcalloc(1, sizeof(*fragment));
- used = 0;
+
+ /* Grab the type of patch */
+ llen = linelen(buffer, size);
+ used = llen;
+ linenr++;
+
+ if (!strncmp(buffer, "delta ", 6)) {
+ patch->is_binary = BINARY_DELTA_DEFLATED;
+ patch->deflate_origlen = strtoul(buffer + 6, NULL, 10);
+ }
+ else if (!strncmp(buffer, "literal ", 8)) {
+ patch->is_binary = BINARY_LITERAL_DEFLATED;
+ patch->deflate_origlen = strtoul(buffer + 8, NULL, 10);
+ }
+ else
+ return error("unrecognized binary patch at line %d: %.*s",
+ linenr-1, llen-1, buffer);
+ buffer += llen;
while (1) {
int byte_length, max_byte_length, newsize;
llen = linelen(buffer, size);
@@ -1015,8 +1036,8 @@
byte_length <= max_byte_length - 4)
goto corrupt;
newsize = fragment->size + byte_length;
- delta = xrealloc(delta, newsize);
- if (decode_85(delta + fragment->size,
+ data = xrealloc(data, newsize);
+ if (decode_85(data + fragment->size,
buffer + 1,
byte_length))
goto corrupt;
@@ -1024,7 +1045,7 @@
buffer += llen;
size -= llen;
}
- fragment->patch = delta;
+ fragment->patch = data;
return used;
corrupt:
return error("corrupt binary patch at line %d: %.*s",
@@ -1425,6 +1446,61 @@
return offset;
}
+static char *inflate_it(const void *data, unsigned long size,
+ unsigned long inflated_size)
+{
+ z_stream stream;
+ void *out;
+ int st;
+
+ memset(&stream, 0, sizeof(stream));
+
+ stream.next_in = (unsigned char *)data;
+ stream.avail_in = size;
+ stream.next_out = out = xmalloc(inflated_size);
+ stream.avail_out = inflated_size;
+ inflateInit(&stream);
+ st = inflate(&stream, Z_FINISH);
+ if ((st != Z_STREAM_END) || stream.total_out != inflated_size) {
+ free(out);
+ return NULL;
+ }
+ return out;
+}
+
+static int apply_binary_fragment(struct buffer_desc *desc, struct patch *patch)
+{
+ unsigned long dst_size;
+ struct fragment *fragment = patch->fragments;
+ void *data;
+ void *result;
+
+ data = inflate_it(fragment->patch, fragment->size,
+ patch->deflate_origlen);
+ if (!data)
+ return error("corrupt patch data");
+ switch (patch->is_binary) {
+ case BINARY_DELTA_DEFLATED:
+ result = patch_delta(desc->buffer, desc->size,
+ data,
+ patch->deflate_origlen,
+ &dst_size);
+ free(desc->buffer);
+ desc->buffer = result;
+ free(data);
+ break;
+ case BINARY_LITERAL_DEFLATED:
+ free(desc->buffer);
+ desc->buffer = data;
+ dst_size = patch->deflate_origlen;
+ break;
+ }
+ if (!desc->buffer)
+ return -1;
+ desc->size = desc->alloc = dst_size;
+ return 0;
+}
+
static int apply_binary(struct buffer_desc *desc, struct patch *patch)
{
const char *name = patch->old_name ? patch->old_name : patch->new_name;
@@ -1466,18 +1542,20 @@
"'%s' but it is not empty", name);
}
- if (desc->buffer) {
+ get_sha1_hex(patch->new_sha1_prefix, sha1);
+ if (!memcmp(sha1, null_sha1, 20)) {
free(desc->buffer);
desc->alloc = desc->size = 0;
- }
- get_sha1_hex(patch->new_sha1_prefix, sha1);
- if (!memcmp(sha1, null_sha1, 20))
+ desc->buffer = NULL;
return 0; /* deletion patch */
+ }
if (has_sha1_file(sha1)) {
+ /* We already have the postimage */
char type[10];
unsigned long size;
+ free(desc->buffer);
desc->buffer = read_sha1_file(sha1, type, &size);
if (!desc->buffer)
return error("the necessary postimage %s for "
@@ -1486,28 +1564,13 @@
desc->alloc = desc->size = size;
}
else {
- char type[10];
- unsigned long src_size, dst_size;
- void *src;
-
- get_sha1_hex(patch->old_sha1_prefix, sha1);
- src = read_sha1_file(sha1, type, &src_size);
- if (!src)
- return error("the necessary preimage %s for "
- "'%s' cannot be read",
- patch->old_sha1_prefix, name);
-
- /* patch->fragment->patch has the delta data and
- * we should apply it to the preimage.
+ /* We have verified desc matches the preimage;
+ * apply the patch data to it, which is stored
+ * in the patch->fragments->{patch,size}.
*/
- desc->buffer = patch_delta(src, src_size,
- (void*) patch->fragments->patch,
- patch->fragments->size,
- &dst_size);
- if (!desc->buffer)
+ if (apply_binary_fragment(desc, patch))
return error("binary patch does not apply to '%s'",
name);
- desc->size = desc->alloc = dst_size;
/* verify that the result matches */
write_sha1_file_prepare(desc->buffer, desc->size, blob_type,
@@ -2102,7 +2165,8 @@
diffstat = 1;
continue;
}
- if (!strcmp(arg, "--allow-binary-replacement")) {
+ if (!strcmp(arg, "--allow-binary-replacement") ||
+ !strcmp(arg, "--binary")) {
allow_binary_replacement = 1;
continue;
}
