diff: fix "multiple regexp" semantics to find hunk header comment

When multiple regular expressions are concatenated with "\n", they were traditionally AND'ed together, and only a line that matches _all_ of them is taken as a match. This however is unwieldy when multiple regexp feature is used to specify alternatives. This fixes the semantics to take the first match. A nagative pattern, if matches, makes the line to fail as before. A match with a positive pattern will be the final match, and what it captures in $1 is used as the hunk header comment. We could write alternatives using "|" in ERE, but the machinery can only use captured $1 as the hunk header comment (or $0 if there is no match in $1), so you cannot write: "junk ( A | B ) | garbage ( C | D )" and expect both "junk" and "garbage" to get stripped with the existing code. With this fix, you can write it as: "junk ( A | B ) \n garbage ( C | D )" and the way capture works would match the user expectation more naturally. Signed-off-by: Junio C Hamano <gitster@pobox.com>

Junio C Hamano committed Sep 20, 2008 at 00:52 UTC 3d8dccd74aa29a9019c4e8b52e75a40189e6f5cb

2 files changed +11 -8

diff.c

+1 -1

@@ -1414,7 +1414,7 @@ static const struct funcname_pattern_entry builtin_funcname_pattern[] = {

1414 { "pascal",

1416 "implementation|initialization|finalization)[ \t]*.*)$"

1417 - "|"

1417 + "\n"

1418 "^(.*=[ \t]*(class|record).*)$",

1419 REG_EXTENDED },

1420 { "php", "^[\t ]*((function|class).*)", REG_EXTENDED },

xdiff-interface.c

+10 -7

@@ -194,26 +194,29 @@ static long ff_regexp(const char *line, long len,

194 char *line_buffer = xstrndup(line, len); /* make NUL terminated */

195 struct ff_regs *regs = priv;

196 regmatch_t pmatch[2];

197 - int result = 0, i;

197 + int i;

198 + int result = -1;

199

200 for (i = 0; i < regs->nr; i++) {

201 struct ff_reg *reg = regs->array + i;

201 - if (reg->negate ^ !!regexec(&reg->re,

202 - line_buffer, 2, pmatch, 0)) {

203 - free(line_buffer);

204 - return -1;

202 + if (!regexec(&reg->re, line_buffer, 2, pmatch, 0)) {

203 + if (reg->negate)

204 + goto fail;

205 + break;

206 }

207 }

208 + if (regs->nr <= i)

209 + goto fail;

210 i = pmatch[1].rm_so >= 0 ? 1 : 0;

211 line += pmatch[i].rm_so;

212 result = pmatch[i].rm_eo - pmatch[i].rm_so;

213 if (result > buffer_size)

214 result = buffer_size;

215 else

213 - while (result > 0 && (isspace(line[result - 1]) ||

214 - line[result - 1] == '\n'))

216 + while (result > 0 && (isspace(line[result - 1])))

217 result--;

218 memcpy(buffer, line, result);

219 + fail:

220 free(line_buffer);

221 return result;

222 }