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Revision b67b9612e1a90ae093445abeaeff930e9f4cf936 authored by Junio C Hamano on 26 January 2009, 08:08:24 UTC, committed by Junio C Hamano on 27 January 2009, 08:48:00 UTC 
diff.c: output correct index lines for a split diff
 
A patch that changes the filetype (e.g. regular file to symlink) of a path
must be split into a deletion event followed by a creation event, which
means that we need to have two independent metainfo lines for each.
However, the code reused the single set of metainfo lines.

As the blob object names recorded on the index lines are usually not used
nor validated on the receiving end, this is not an issue with normal use
of the resulting patch.  However, when accepting a binary patch to delete
a blob, git-apply verified that the postimage blob object name on the
index line is 0{40}, hence a patch that deletes a regular file blob that
records binary contents to create a blob with different filetype (e.g. a
symbolic link) failed to apply.  "git am -3" also uses the blob object
names recorded on the index line, so it would also misbehave when
synthesizing a preimage tree.

This moves the code to generate metainfo lines around, so that two
independent sets of metainfo lines are used for the split halves.

Additional tests by Jeff King.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent b938f62
Raw File
mktree.c 
/*
 * GIT - the stupid content tracker
 *
 * Copyright (c) Junio C Hamano, 2006
 */
#include "cache.h"
#include "quote.h"
#include "tree.h"

static struct treeent {
	unsigned mode;
	unsigned char sha1[20];
	int len;
	char name[FLEX_ARRAY];
} **entries;
static int alloc, used;

static void append_to_tree(unsigned mode, unsigned char *sha1, char *path)
{
	struct treeent *ent;
	int len = strlen(path);
	if (strchr(path, '/'))
		die("path %s contains slash", path);

	if (alloc <= used) {
		alloc = alloc_nr(used);
		entries = xrealloc(entries, sizeof(*entries) * alloc);
	}
	ent = entries[used++] = xmalloc(sizeof(**entries) + len + 1);
	ent->mode = mode;
	ent->len = len;
	hashcpy(ent->sha1, sha1);
	memcpy(ent->name, path, len+1);
}

static int ent_compare(const void *a_, const void *b_)
{
	struct treeent *a = *(struct treeent **)a_;
	struct treeent *b = *(struct treeent **)b_;
	return base_name_compare(a->name, a->len, a->mode,
				 b->name, b->len, b->mode);
}

static void write_tree(unsigned char *sha1)
{
	struct strbuf buf;
	size_t size;
	int i;

	qsort(entries, used, sizeof(*entries), ent_compare);
	for (size = i = 0; i < used; i++)
		size += 32 + entries[i]->len;

	strbuf_init(&buf, size);
	for (i = 0; i < used; i++) {
		struct treeent *ent = entries[i];
		strbuf_addf(&buf, "%o %s%c", ent->mode, ent->name, '\0');
		strbuf_add(&buf, ent->sha1, 20);
	}

	write_sha1_file(buf.buf, buf.len, tree_type, sha1);
}

static const char mktree_usage[] = "git-mktree [-z]";

int main(int ac, char **av)
{
	struct strbuf sb;
	struct strbuf p_uq;
	unsigned char sha1[20];
	int line_termination = '\n';

	setup_git_directory();

	while ((1 < ac) && av[1][0] == '-') {
		char *arg = av[1];
		if (!strcmp("-z", arg))
			line_termination = 0;
		else
			usage(mktree_usage);
		ac--;
		av++;
	}

	strbuf_init(&sb, 0);
	strbuf_init(&p_uq, 0);
	while (strbuf_getline(&sb, stdin, line_termination) != EOF) {
		char *ptr, *ntr;
		unsigned mode;
		enum object_type type;
		char *path;

		ptr = sb.buf;
		/* Input is non-recursive ls-tree output format
		 * mode SP type SP sha1 TAB name
		 */
		mode = strtoul(ptr, &ntr, 8);
		if (ptr == ntr || !ntr || *ntr != ' ')
			die("input format error: %s", sb.buf);
		ptr = ntr + 1; /* type */
		ntr = strchr(ptr, ' ');
		if (!ntr || sb.buf + sb.len <= ntr + 40 ||
		    ntr[41] != '\t' ||
		    get_sha1_hex(ntr + 1, sha1))
			die("input format error: %s", sb.buf);
		type = sha1_object_info(sha1, NULL);
		if (type < 0)
			die("object %s unavailable", sha1_to_hex(sha1));
		*ntr++ = 0; /* now at the beginning of SHA1 */
		if (type != type_from_string(ptr))
			die("object type %s mismatch (%s)", ptr, typename(type));

		path = ntr + 41;  /* at the beginning of name */
		if (line_termination && path[0] == '"') {
			strbuf_reset(&p_uq);
			if (unquote_c_style(&p_uq, path, NULL)) {
				die("invalid quoting");
			}
			path = p_uq.buf;
		}

		append_to_tree(mode, sha1, path);
	}
	strbuf_release(&p_uq);
	strbuf_release(&sb);

	write_tree(sha1);
	puts(sha1_to_hex(sha1));
	exit(0);
}
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