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git-apply --binary: clean up and prepare for --reverse
This cleans up the implementation of "git-apply --binary", and implements reverse application of binary patches (when git-diff is converted to emit reversible binary patches). Earlier, the types of encoding (either deflated literal or deflated delta) were stored in is_binary field in struct patch, which meant that we cannot store more than one fragment that differ in the encoding for a patch. This moves the information to a field in struct fragment that is otherwise unused for binary patches, and makes it possible to hang two (or more, but two is enough) hunks for a binary patch. The original "binary patch" output from git-diff is internally parsed into an "is_binary" patch with one fragment. Upcoming reversible binary patch output will have two fragments, the first one being the forward patch and the second one the reverse patch. Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Junio C Hamano
parent
d1b9944db8
commit
3cd4f5e8eb
206
builtin-apply.c
206
builtin-apply.c
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@ -109,6 +109,13 @@ static int max_change, max_len;
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*/
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static int linenr = 1;
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/*
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* This represents one "hunk" from a patch, starting with
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* "@@ -oldpos,oldlines +newpos,newlines @@" marker. The
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* patch text is pointed at by patch, and its byte length
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* is stored in size. leading and trailing are the number
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* of context lines.
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*/
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struct fragment {
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unsigned long leading, trailing;
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unsigned long oldpos, oldlines;
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@ -118,12 +125,19 @@ struct fragment {
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struct fragment *next;
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};
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/*
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* When dealing with a binary patch, we reuse "leading" field
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* to store the type of the binary hunk, either deflated "delta"
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* or deflated "literal".
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*/
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#define binary_patch_method leading
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#define BINARY_DELTA_DEFLATED 1
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#define BINARY_LITERAL_DEFLATED 2
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struct patch {
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char *new_name, *old_name, *def_name;
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unsigned int old_mode, new_mode;
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int is_rename, is_copy, is_new, is_delete, is_binary;
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#define BINARY_DELTA_DEFLATED 1
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#define BINARY_LITERAL_DEFLATED 2
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unsigned long deflate_origlen;
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int lines_added, lines_deleted;
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int score;
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@ -979,43 +993,70 @@ static inline int metadata_changes(struct patch *patch)
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patch->old_mode != patch->new_mode);
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}
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static int parse_binary(char *buffer, unsigned long size, struct patch *patch)
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static char *inflate_it(const void *data, unsigned long size,
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unsigned long inflated_size)
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{
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/* We have read "GIT binary patch\n"; what follows is a line
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* that says the patch method (currently, either "deflated
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* literal" or "deflated delta") and the length of data before
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* deflating; a sequence of 'length-byte' followed by base-85
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* encoded data follows.
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z_stream stream;
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void *out;
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int st;
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memset(&stream, 0, sizeof(stream));
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stream.next_in = (unsigned char *)data;
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stream.avail_in = size;
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stream.next_out = out = xmalloc(inflated_size);
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stream.avail_out = inflated_size;
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inflateInit(&stream);
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st = inflate(&stream, Z_FINISH);
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if ((st != Z_STREAM_END) || stream.total_out != inflated_size) {
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free(out);
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return NULL;
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}
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return out;
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}
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static struct fragment *parse_binary_hunk(char **buf_p,
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unsigned long *sz_p,
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int *status_p,
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int *used_p)
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{
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/* Expect a line that begins with binary patch method ("literal"
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* or "delta"), followed by the length of data before deflating.
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* a sequence of 'length-byte' followed by base-85 encoded data
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* should follow, terminated by a newline.
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*
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* Each 5-byte sequence of base-85 encodes up to 4 bytes,
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* and we would limit the patch line to 66 characters,
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* so one line can fit up to 13 groups that would decode
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* to 52 bytes max. The length byte 'A'-'Z' corresponds
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* to 1-26 bytes, and 'a'-'z' corresponds to 27-52 bytes.
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* The end of binary is signaled with an empty line.
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*/
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int llen, used;
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struct fragment *fragment;
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unsigned long size = *sz_p;
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char *buffer = *buf_p;
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int patch_method;
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unsigned long origlen;
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char *data = NULL;
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int hunk_size = 0;
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struct fragment *frag;
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patch->fragments = fragment = xcalloc(1, sizeof(*fragment));
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/* Grab the type of patch */
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llen = linelen(buffer, size);
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used = llen;
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linenr++;
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*status_p = 0;
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if (!strncmp(buffer, "delta ", 6)) {
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patch->is_binary = BINARY_DELTA_DEFLATED;
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patch->deflate_origlen = strtoul(buffer + 6, NULL, 10);
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patch_method = BINARY_DELTA_DEFLATED;
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origlen = strtoul(buffer + 6, NULL, 10);
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}
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else if (!strncmp(buffer, "literal ", 8)) {
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patch->is_binary = BINARY_LITERAL_DEFLATED;
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patch->deflate_origlen = strtoul(buffer + 8, NULL, 10);
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patch_method = BINARY_LITERAL_DEFLATED;
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origlen = strtoul(buffer + 8, NULL, 10);
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}
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else
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return error("unrecognized binary patch at line %d: %.*s",
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linenr-1, llen-1, buffer);
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return NULL;
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linenr++;
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buffer += llen;
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while (1) {
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int byte_length, max_byte_length, newsize;
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@ -1044,21 +1085,79 @@ static int parse_binary(char *buffer, unsigned long size, struct patch *patch)
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if (max_byte_length < byte_length ||
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byte_length <= max_byte_length - 4)
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goto corrupt;
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newsize = fragment->size + byte_length;
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newsize = hunk_size + byte_length;
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data = xrealloc(data, newsize);
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if (decode_85(data + fragment->size,
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buffer + 1,
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byte_length))
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if (decode_85(data + hunk_size, buffer + 1, byte_length))
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goto corrupt;
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fragment->size = newsize;
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hunk_size = newsize;
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buffer += llen;
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size -= llen;
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}
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fragment->patch = data;
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return used;
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frag = xcalloc(1, sizeof(*frag));
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frag->patch = inflate_it(data, hunk_size, origlen);
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if (!frag->patch)
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goto corrupt;
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free(data);
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frag->size = origlen;
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*buf_p = buffer;
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*sz_p = size;
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*used_p = used;
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frag->binary_patch_method = patch_method;
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return frag;
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corrupt:
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return error("corrupt binary patch at line %d: %.*s",
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linenr-1, llen-1, buffer);
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if (data)
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free(data);
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*status_p = -1;
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error("corrupt binary patch at line %d: %.*s",
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linenr-1, llen-1, buffer);
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return NULL;
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}
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static int parse_binary(char *buffer, unsigned long size, struct patch *patch)
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{
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/* We have read "GIT binary patch\n"; what follows is a line
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* that says the patch method (currently, either "literal" or
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* "delta") and the length of data before deflating; a
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* sequence of 'length-byte' followed by base-85 encoded data
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* follows.
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*
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* When a binary patch is reversible, there is another binary
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* hunk in the same format, starting with patch method (either
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* "literal" or "delta") with the length of data, and a sequence
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* of length-byte + base-85 encoded data, terminated with another
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* empty line. This data, when applied to the postimage, produces
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* the preimage.
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*/
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struct fragment *forward;
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struct fragment *reverse;
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int status;
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int used, used_1;
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forward = parse_binary_hunk(&buffer, &size, &status, &used);
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if (!forward && !status)
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/* there has to be one hunk (forward hunk) */
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return error("unrecognized binary patch at line %d", linenr-1);
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if (status)
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/* otherwise we already gave an error message */
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return status;
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reverse = parse_binary_hunk(&buffer, &size, &status, &used_1);
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if (reverse)
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used += used_1;
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else if (status) {
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/* not having reverse hunk is not an error, but having
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* a corrupt reverse hunk is.
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*/
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free((void*) forward->patch);
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free(forward);
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return status;
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}
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forward->next = reverse;
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patch->fragments = forward;
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patch->is_binary = 1;
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return used;
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}
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static int parse_chunk(char *buffer, unsigned long size, struct patch *patch)
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@ -1505,28 +1604,6 @@ static int apply_one_fragment(struct buffer_desc *desc, struct fragment *frag, i
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return offset;
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}
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static char *inflate_it(const void *data, unsigned long size,
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unsigned long inflated_size)
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{
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z_stream stream;
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void *out;
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int st;
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memset(&stream, 0, sizeof(stream));
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stream.next_in = (unsigned char *)data;
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stream.avail_in = size;
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stream.next_out = out = xmalloc(inflated_size);
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stream.avail_out = inflated_size;
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inflateInit(&stream);
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st = inflate(&stream, Z_FINISH);
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if ((st != Z_STREAM_END) || stream.total_out != inflated_size) {
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free(out);
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return NULL;
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}
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return out;
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}
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static int apply_binary_fragment(struct buffer_desc *desc, struct patch *patch)
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{
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unsigned long dst_size;
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@ -1534,30 +1611,29 @@ static int apply_binary_fragment(struct buffer_desc *desc, struct patch *patch)
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void *data;
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void *result;
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/* Binary patch is irreversible */
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if (apply_in_reverse)
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return error("cannot reverse-apply a binary patch to '%s'",
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patch->new_name
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? patch->new_name : patch->old_name);
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data = inflate_it(fragment->patch, fragment->size,
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patch->deflate_origlen);
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if (!data)
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return error("corrupt patch data");
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switch (patch->is_binary) {
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/* Binary patch is irreversible without the optional second hunk */
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if (apply_in_reverse) {
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if (!fragment->next)
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return error("cannot reverse-apply a binary patch "
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"without the reverse hunk to '%s'",
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patch->new_name
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? patch->new_name : patch->old_name);
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fragment = fragment;
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}
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data = (void*) fragment->patch;
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switch (fragment->binary_patch_method) {
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case BINARY_DELTA_DEFLATED:
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result = patch_delta(desc->buffer, desc->size,
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data,
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patch->deflate_origlen,
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fragment->size,
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&dst_size);
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free(desc->buffer);
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desc->buffer = result;
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free(data);
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break;
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case BINARY_LITERAL_DEFLATED:
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free(desc->buffer);
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desc->buffer = data;
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dst_size = patch->deflate_origlen;
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dst_size = fragment->size;
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break;
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}
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if (!desc->buffer)
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