I attempted to make index_state->cache[] a "const struct cache_entry **"
to find out how existing entries in index are modified and where. The
question I have is what do we do if we really need to keep track of on-disk
changes in the index. The result is
 - diff-lib.c: setting CE_UPTODATE
 - name-hash.c: setting CE_HASHED
 - preload-index.c, read-cache.c, unpack-trees.c and
   builtin/update-index: obvious
 - entry.c: write_entry() may refresh the checked out entry via
   fill_stat_cache_info(). This causes "non-const struct cache_entry
   *" in builtin/apply.c, builtin/checkout-index.c and
   builtin/checkout.c
 - builtin/ls-files.c: --with-tree changes stagemask and may set
   CE_UPDATE
Of these, write_entry() and its call sites are probably most
interesting because it modifies on-disk info. But this is stat info
and can be retrieved via refresh, at least for porcelain
commands. Other just uses ce_flags for local purposes.
So, keeping track of "dirty" entries is just a matter of setting a
flag in index modification functions exposed by read-cache.c. Except
unpack-trees, the rest of the code base does not do anything funny
behind read-cache's back.
The actual patch is less valueable than the summary above. But if
anyone wants to re-identify the above sites. Applying this patch, then
this:
    diff --git a/cache.h b/cache.h
    index 430d021..1692891 100644
    --- a/cache.h
    +++ b/cache.h
    @@ -267,7 +267,7 @@ static inline unsigned int canon_mode(unsigned int mode)
     #define cache_entry_size(len) (offsetof(struct cache_entry,name) + (len) + 1)
     struct index_state {
    -	struct cache_entry **cache;
    +	const struct cache_entry **cache;
     	unsigned int version;
     	unsigned int cache_nr, cache_alloc, cache_changed;
     	struct string_list *resolve_undo;
will help quickly identify them without bogus warnings.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
		
	
		
			
				
	
	
		
			111 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			111 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
#include "builtin.h"
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#include "run-command.h"
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static const char *pgm;
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static int one_shot, quiet;
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static int err;
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static int merge_entry(int pos, const char *path)
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{
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	int found;
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	const char *arguments[] = { pgm, "", "", "", path, "", "", "", NULL };
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	char hexbuf[4][60];
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	char ownbuf[4][60];
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	if (pos >= active_nr)
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		die("git merge-index: %s not in the cache", path);
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	found = 0;
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	do {
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		const struct cache_entry *ce = active_cache[pos];
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		int stage = ce_stage(ce);
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		if (strcmp(ce->name, path))
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			break;
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		found++;
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		strcpy(hexbuf[stage], sha1_to_hex(ce->sha1));
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		sprintf(ownbuf[stage], "%o", ce->ce_mode);
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		arguments[stage] = hexbuf[stage];
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		arguments[stage + 4] = ownbuf[stage];
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	} while (++pos < active_nr);
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	if (!found)
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		die("git merge-index: %s not in the cache", path);
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	if (run_command_v_opt(arguments, 0)) {
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		if (one_shot)
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			err++;
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		else {
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			if (!quiet)
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				die("merge program failed");
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			exit(1);
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		}
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	}
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	return found;
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}
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static void merge_one_path(const char *path)
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{
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	int pos = cache_name_pos(path, strlen(path));
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	/*
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	 * If it already exists in the cache as stage0, it's
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	 * already merged and there is nothing to do.
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	 */
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	if (pos < 0)
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		merge_entry(-pos-1, path);
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}
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static void merge_all(void)
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{
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	int i;
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	for (i = 0; i < active_nr; i++) {
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		const struct cache_entry *ce = active_cache[i];
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		if (!ce_stage(ce))
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			continue;
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		i += merge_entry(i, ce->name)-1;
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	}
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}
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int cmd_merge_index(int argc, const char **argv, const char *prefix)
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{
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	int i, force_file = 0;
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	/* Without this we cannot rely on waitpid() to tell
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	 * what happened to our children.
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	 */
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	signal(SIGCHLD, SIG_DFL);
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	if (argc < 3)
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		usage("git merge-index [-o] [-q] <merge-program> (-a | [--] <filename>*)");
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	read_cache();
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	i = 1;
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	if (!strcmp(argv[i], "-o")) {
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		one_shot = 1;
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		i++;
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	}
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	if (!strcmp(argv[i], "-q")) {
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		quiet = 1;
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		i++;
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	}
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	pgm = argv[i++];
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	for (; i < argc; i++) {
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		const char *arg = argv[i];
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		if (!force_file && *arg == '-') {
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			if (!strcmp(arg, "--")) {
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				force_file = 1;
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				continue;
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			}
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			if (!strcmp(arg, "-a")) {
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				merge_all();
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				continue;
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			}
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			die("git merge-index: unknown option %s", arg);
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		}
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		merge_one_path(arg);
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	}
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	if (err && !quiet)
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		die("merge program failed");
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	return err;
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}
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