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diff: vary default prefix depending on what are compared

With a new configuration "diff.mnemonicprefix", "git diff" shows the
differences between various combinations of preimage and postimage trees
with prefixes different from the standard "a/" and "b/".  Hopefully this
will make the distinction stand out for some people.

    "git diff" compares the (i)ndex and the (w)ork tree;
    "git diff HEAD" compares a (c)ommit and the (w)ork tree;
    "git diff --cached" compares a (c)ommit and the (i)ndex;
    "git-diff HEAD:file1 file2" compares an (o)bject and a (w)ork tree entity;
    "git diff --no-index a b" compares two non-git things (1) and (2).

Because these mnemonics now have meanings, they are swapped when reverse
diff is in effect and this feature is enabled.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
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1 parent 53d1589 commit a5a818ee4877e4458e8e6741a03ac3b19941d58a @gitster gitster committed Aug 19, 2008
Showing with 70 additions and 8 deletions.
  1. +16 −0 Documentation/config.txt
  2. +2 −0 builtin-diff.c
  3. +6 −2 combine-diff.c
  4. +3 −0 diff-lib.c
  5. +1 −0 diff-no-index.c
  6. +40 −6 diff.c
  7. +2 −0 diff.h
View
@@ -581,6 +581,22 @@ diff.external::
you want to use an external diff program only on a subset of
your files, you might want to use linkgit:gitattributes[5] instead.
+diff.mnemonicprefix::
+ If set, 'git-diff' uses a prefix pair that is different from the
+ standard "a/" and "b/" depending on what is being compared. When
+ this configuration is in effect, reverse diff output also swaps
+ the order of the prefixes:
+'git-diff';;
+ compares the (i)ndex and the (w)ork tree;
+'git-diff HEAD';;
+ compares a (c)ommit and the (w)ork tree;
+'git diff --cached';;
+ compares a (c)ommit and the (i)ndex;
+'git-diff HEAD:file1 file2';;
+ compares an (o)bject and a (w)ork tree entity;
+'git diff --no-index a b';;
+ compares two non-git things (1) and (2).
+
diff.renameLimit::
The number of files to consider when performing the copy/rename
detection; equivalent to the 'git-diff' option '-l'.
View
@@ -74,6 +74,8 @@ static int builtin_diff_b_f(struct rev_info *revs,
if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
die("'%s': not a regular file or symlink", path);
+ diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
+
if (blob[0].mode == S_IFINVALID)
blob[0].mode = canon_mode(st.st_mode);
View
@@ -675,9 +675,13 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
int i, show_hunks;
int working_tree_file = is_null_sha1(elem->sha1);
int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
+ const char *a_prefix, *b_prefix;
mmfile_t result_file;
context = opt->context;
+ a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
+ b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
+
/* Read the result of merge first */
if (!working_tree_file)
result = grab_blob(elem->sha1, &result_size);
@@ -853,13 +857,13 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
dump_quoted_path("--- ", "", "/dev/null",
c_meta, c_reset);
else
- dump_quoted_path("--- ", opt->a_prefix, elem->path,
+ dump_quoted_path("--- ", a_prefix, elem->path,
c_meta, c_reset);
if (deleted)
dump_quoted_path("+++ ", "", "/dev/null",
c_meta, c_reset);
else
- dump_quoted_path("+++ ", opt->b_prefix, elem->path,
+ dump_quoted_path("+++ ", b_prefix, elem->path,
c_meta, c_reset);
dump_sline(sline, cnt, num_parent,
DIFF_OPT_TST(opt, COLOR_DIFF));
View
@@ -63,6 +63,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
? CE_MATCH_RACY_IS_DIRTY : 0);
char symcache[PATH_MAX];
+ diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
+
if (diff_unmerged_stage < 0)
diff_unmerged_stage = 2;
entries = active_nr;
@@ -469,6 +471,7 @@ int run_diff_index(struct rev_info *revs, int cached)
if (unpack_trees(1, &t, &opts))
exit(128);
+ diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
diffcore_std(&revs->diffopt);
diff_flush(&revs->diffopt);
return 0;
View
@@ -252,6 +252,7 @@ void diff_no_index(struct rev_info *revs,
if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
revs->diffopt.paths[1]))
exit(1);
+ diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
diffcore_std(&revs->diffopt);
diff_flush(&revs->diffopt);
View
46 diff.c
@@ -23,6 +23,7 @@ static int diff_rename_limit_default = 200;
int diff_use_color_default = -1;
static const char *external_diff_cmd_cfg;
int diff_auto_refresh_index = 1;
+static int diff_mnemonic_prefix;
static char diff_colors[][COLOR_MAXLEN] = {
"\033[m", /* reset */
@@ -149,6 +150,10 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
diff_auto_refresh_index = git_config_bool(var, value);
return 0;
}
+ if (!strcmp(var, "diff.mnemonicprefix")) {
+ diff_mnemonic_prefix = git_config_bool(var, value);
+ return 0;
+ }
if (!strcmp(var, "diff.external"))
return git_config_string(&external_diff_cmd_cfg, var, value);
if (!prefixcmp(var, "diff.")) {
@@ -305,6 +310,15 @@ static void emit_rewrite_diff(const char *name_a,
const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
const char *reset = diff_get_color(color_diff, DIFF_RESET);
static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
+ const char *a_prefix, *b_prefix;
+
+ if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
+ a_prefix = o->b_prefix;
+ b_prefix = o->a_prefix;
+ } else {
+ a_prefix = o->a_prefix;
+ b_prefix = o->b_prefix;
+ }
name_a += (*name_a == '/');
name_b += (*name_b == '/');
@@ -313,8 +327,8 @@ static void emit_rewrite_diff(const char *name_a,
strbuf_reset(&a_name);
strbuf_reset(&b_name);
- quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
- quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
+ quote_two_c_style(&a_name, a_prefix, name_a, 0);
+ quote_two_c_style(&b_name, b_prefix, name_b, 0);
diff_populate_filespec(one, 0);
diff_populate_filespec(two, 0);
@@ -1432,6 +1446,14 @@ static const char *diff_funcname_pattern(struct diff_filespec *one)
return NULL;
}
+void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
+{
+ if (!options->a_prefix)
+ options->a_prefix = a;
+ if (!options->b_prefix)
+ options->b_prefix = b;
+}
+
static void builtin_diff(const char *name_a,
const char *name_b,
struct diff_filespec *one,
@@ -1445,9 +1467,19 @@ static void builtin_diff(const char *name_a,
char *a_one, *b_two;
const char *set = diff_get_color_opt(o, DIFF_METAINFO);
const char *reset = diff_get_color_opt(o, DIFF_RESET);
+ const char *a_prefix, *b_prefix;
+
+ diff_set_mnemonic_prefix(o, "a/", "b/");
+ if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
+ a_prefix = o->b_prefix;
+ b_prefix = o->a_prefix;
+ } else {
+ a_prefix = o->a_prefix;
+ b_prefix = o->b_prefix;
+ }
- a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
- b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
+ a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
+ b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
@@ -2308,8 +2340,10 @@ void diff_setup(struct diff_options *options)
DIFF_OPT_CLR(options, COLOR_DIFF);
options->detect_rename = diff_detect_rename_default;
- options->a_prefix = "a/";
- options->b_prefix = "b/";
+ if (!diff_mnemonic_prefix) {
+ options->a_prefix = "a/";
+ options->b_prefix = "b/";
+ }
}
int diff_setup_done(struct diff_options *options)
View
2 diff.h
@@ -160,6 +160,8 @@ extern void diff_tree_combined(const unsigned char *sha1, const unsigned char pa
extern void diff_tree_combined_merge(const unsigned char *sha1, int, struct rev_info *);
+void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b);
+
extern void diff_addremove(struct diff_options *,
int addremove,
unsigned mode,

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