diff: add option to show whole functions as context

Add the option -W/--function-context to git diff.  It is similar to
the same option of git grep and expands the context of change hunks
so that the whole surrounding function is shown.  This "natural"
context can allow changes to be understood better.

Note: GNU patch doesn't like diffs generated with the new option;
it seems to expect context lines to be the same before and after
changes.  git apply doesn't complain.

This implementation has the same shortcoming as the one in grep,
namely that there is no way to explicitly find the end of a
function.  That means that a few lines of extra context are shown,
right up to the next recognized function begins.  It's already
useful in its current form, though.

The function get_func_line() in xdiff/xemit.c is extended to work
forward as well as backward to find post-context as well as
pre-context.  It returns the position of the first found matching
line.  The func_line parameter is made optional, as we don't need
it for -W.

The enhanced function is then used in xdl_emit_diff() to extend
the context as needed.  If the added context overlaps with the
next change, it is merged into the current hunk.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
René Scharfe 2011-10-09 13:36:57 +02:00 committed by Junio C Hamano
parent f99f4b3667
commit 14937c2c06
6 changed files with 154 additions and 6 deletions

View File

@ -404,6 +404,10 @@ endif::git-format-patch[]
Show the context between diff hunks, up to the specified number
of lines, thereby fusing hunks that are close to each other.
-W::
--function-context::
Show whole surrounding functions of changes.
ifndef::git-format-patch[]
--exit-code::
Make the program exit with codes similar to diff(1).

8
diff.c
View File

@ -2169,6 +2169,8 @@ static void builtin_diff(const char *name_a,
xecfg.ctxlen = o->context;
xecfg.interhunkctxlen = o->interhunkcontext;
xecfg.flags = XDL_EMIT_FUNCNAMES;
if (DIFF_OPT_TST(o, FUNCCONTEXT))
xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
if (pe)
xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
if (!diffopts)
@ -3530,6 +3532,12 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
else if (opt_arg(arg, '\0', "inter-hunk-context",
&options->interhunkcontext))
;
else if (!strcmp(arg, "-W"))
DIFF_OPT_SET(options, FUNCCONTEXT);
else if (!strcmp(arg, "--function-context"))
DIFF_OPT_SET(options, FUNCCONTEXT);
else if (!strcmp(arg, "--no-function-context"))
DIFF_OPT_CLR(options, FUNCCONTEXT);
else if ((argcount = parse_long_opt("output", av, &optarg))) {
options->file = fopen(optarg, "w");
if (!options->file)

1
diff.h
View File

@ -79,6 +79,7 @@ typedef struct strbuf *(*diff_prefix_fn_t)(struct diff_options *opt, void *data)
#define DIFF_OPT_IGNORE_DIRTY_SUBMODULES (1 << 26)
#define DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG (1 << 27)
#define DIFF_OPT_DIRSTAT_BY_LINE (1 << 28)
#define DIFF_OPT_FUNCCONTEXT (1 << 29)
#define DIFF_OPT_TST(opts, flag) ((opts)->flags & DIFF_OPT_##flag)
#define DIFF_OPT_SET(opts, flag) ((opts)->flags |= DIFF_OPT_##flag)

View File

@ -0,0 +1,92 @@
#!/bin/sh
test_description='diff function context'
. ./test-lib.sh
. "$TEST_DIRECTORY"/diff-lib.sh
cat <<\EOF >hello.c
#include <stdio.h>
static int a(void)
{
/*
* Dummy.
*/
}
static int hello_world(void)
{
/* Classic. */
printf("Hello world.\n");
/* Success! */
return 0;
}
static int b(void)
{
/*
* Dummy, too.
*/
}
int main(int argc, char **argv)
{
a();
b();
return hello_world();
}
EOF
test_expect_success 'setup' '
git add hello.c &&
test_tick &&
git commit -m initial &&
grep -v Classic <hello.c >hello.c.new &&
mv hello.c.new hello.c
'
cat <<\EOF >expected
diff --git a/hello.c b/hello.c
--- a/hello.c
+++ b/hello.c
@@ -10,8 +10,7 @@ static int a(void)
static int hello_world(void)
{
- /* Classic. */
printf("Hello world.\n");
/* Success! */
return 0;
}
EOF
test_expect_success 'diff -U0 -W' '
git diff -U0 -W >actual &&
compare_diff_patch actual expected
'
cat <<\EOF >expected
diff --git a/hello.c b/hello.c
--- a/hello.c
+++ b/hello.c
@@ -9,9 +9,8 @@ static int a(void)
static int hello_world(void)
{
- /* Classic. */
printf("Hello world.\n");
/* Success! */
return 0;
}
EOF
test_expect_success 'diff -W' '
git diff -W >actual &&
compare_diff_patch actual expected
'
test_done

View File

@ -43,6 +43,7 @@ extern "C" {
#define XDL_EMIT_FUNCNAMES (1 << 0)
#define XDL_EMIT_COMMON (1 << 1)
#define XDL_EMIT_FUNCCONTEXT (1 << 2)
#define XDL_MMB_READONLY (1 << 0)

View File

@ -105,22 +105,27 @@ struct func_line {
char buf[80];
};
static void get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
struct func_line *func_line, long start, long limit)
{
find_func_t ff = xecfg->find_func ? xecfg->find_func : def_ff;
long l, size = sizeof(func_line->buf);
char *buf = func_line->buf;
long l, size, step = (start > limit) ? -1 : 1;
char *buf, dummy[1];
for (l = start; l > limit && 0 <= l; l--) {
buf = func_line ? func_line->buf : dummy;
size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
const char *rec;
long reclen = xdl_get_rec(&xe->xdf1, l, &rec);
long len = ff(rec, reclen, buf, size, xecfg->find_func_priv);
if (len >= 0) {
func_line->len = len;
break;
if (func_line)
func_line->len = len;
return l;
}
}
return -1;
}
int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
@ -139,6 +144,17 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
long fs1 = get_func_line(xe, xecfg, NULL, xch->i1, -1);
if (fs1 < 0)
fs1 = 0;
if (fs1 < s1) {
s2 -= s1 - fs1;
s1 = fs1;
}
}
again:
lctx = xecfg->ctxlen;
lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
@ -146,6 +162,32 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
e1 = xche->i1 + xche->chg1 + lctx;
e2 = xche->i2 + xche->chg2 + lctx;
if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
long fe1 = get_func_line(xe, xecfg, NULL,
xche->i1 + xche->chg1,
xe->xdf1.nrec);
if (fe1 < 0)
fe1 = xe->xdf1.nrec;
if (fe1 > e1) {
e2 += fe1 - e1;
e1 = fe1;
}
/*
* Overlap with next change? Then include it
* in the current hunk and start over to find
* its new end.
*/
if (xche->next) {
long l = xche->next->i1;
if (l <= e1 ||
get_func_line(xe, xecfg, NULL, l, e1) < 0) {
xche = xche->next;
goto again;
}
}
}
/*
* Emit current hunk header.
*/