git

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/*
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 * Copyright (C) 2005 Junio C Hamano
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 * Copyright (C) 2010 Google Inc.
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 */
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#include "git-compat-util.h"
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#include "diff.h"
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#include "diffcore.h"
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#include "xdiff-interface.h"
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#include "kwset.h"
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#include "oidset.h"
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#include "pretty.h"
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#include "quote.h"
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typedef int (*pickaxe_fn)(mmfile_t *one, mmfile_t *two,
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			  struct diff_options *o,
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			  regex_t *regexp, kwset_t kws);
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struct diffgrep_cb {
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	regex_t *regexp;
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	int hit;
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};
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static int diffgrep_consume(void *priv, char *line, unsigned long len)
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{
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	struct diffgrep_cb *data = priv;
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	regmatch_t regmatch;
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	if (line[0] != '+' && line[0] != '-')
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		return 0;
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	if (data->hit)
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		BUG("Already matched in diffgrep_consume! Broken xdiff_emit_line_fn?");
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	if (!regexec_buf(data->regexp, line + 1, len - 1, 1,
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			 &regmatch, 0)) {
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		data->hit = 1;
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		return 1;
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	}
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	return 0;
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}
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static int diff_grep(mmfile_t *one, mmfile_t *two,
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		     struct diff_options *o,
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		     regex_t *regexp, kwset_t kws UNUSED)
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{
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	struct diffgrep_cb ecbdata;
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	xpparam_t xpp;
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	xdemitconf_t xecfg;
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	int ret;
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	/*
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	 * We have both sides; need to run textual diff and see if
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	 * the pattern appears on added/deleted lines.
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	 */
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	memset(&xpp, 0, sizeof(xpp));
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	memset(&xecfg, 0, sizeof(xecfg));
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	ecbdata.regexp = regexp;
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	ecbdata.hit = 0;
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	xecfg.flags = XDL_EMIT_NO_HUNK_HDR;
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	xecfg.ctxlen = o->context;
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	xecfg.interhunkctxlen = o->interhunkcontext;
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	/*
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	 * An xdiff error might be our "data->hit" from above. See the
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	 * comment for xdiff_emit_line_fn in xdiff-interface.h
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	 */
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	ret = xdi_diff_outf(one, two, NULL, diffgrep_consume,
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			    &ecbdata, &xpp, &xecfg);
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	if (ecbdata.hit)
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		return 1;
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	if (ret)
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		return ret;
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	return 0;
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}
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static unsigned int contains(mmfile_t *mf, regex_t *regexp, kwset_t kws,
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			     unsigned int limit)
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{
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	unsigned int cnt = 0;
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	unsigned long sz = mf->size;
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	const char *data = mf->ptr;
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	if (regexp) {
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		regmatch_t regmatch;
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		int flags = 0;
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		while (sz &&
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		       !regexec_buf(regexp, data, sz, 1, &regmatch, flags)) {
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			flags |= REG_NOTBOL;
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			data += regmatch.rm_eo;
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			sz -= regmatch.rm_eo;
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			if (sz && regmatch.rm_so == regmatch.rm_eo) {
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				data++;
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				sz--;
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			}
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			cnt++;
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			if (limit && cnt == limit)
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				return cnt;
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		}
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	} else { /* Classic exact string match */
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		while (sz) {
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			struct kwsmatch kwsm;
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			size_t offset = kwsexec(kws, data, sz, &kwsm);
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			if (offset == -1)
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				break;
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			sz -= offset + kwsm.size[0];
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			data += offset + kwsm.size[0];
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			cnt++;
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			if (limit && cnt == limit)
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				return cnt;
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		}
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	}
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	return cnt;
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}
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static int has_changes(mmfile_t *one, mmfile_t *two,
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		       struct diff_options *o UNUSED,
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		       regex_t *regexp, kwset_t kws)
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{
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	unsigned int c1 = one ? contains(one, regexp, kws, 0) : 0;
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	unsigned int c2 = two ? contains(two, regexp, kws, c1 + 1) : 0;
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	return c1 != c2;
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}
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static int pickaxe_match(struct diff_filepair *p, struct diff_options *o,
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			 regex_t *regexp, kwset_t kws, pickaxe_fn fn)
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{
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	struct userdiff_driver *textconv_one = NULL;
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	struct userdiff_driver *textconv_two = NULL;
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	mmfile_t mf1, mf2;
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	int ret;
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	/* ignore unmerged */
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	if (!DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two))
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		return 0;
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	if (o->objfind) {
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		return  (DIFF_FILE_VALID(p->one) &&
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			 oidset_contains(o->objfind, &p->one->oid)) ||
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			(DIFF_FILE_VALID(p->two) &&
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			 oidset_contains(o->objfind, &p->two->oid));
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	}
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	if (o->flags.allow_textconv) {
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		textconv_one = get_textconv(o->repo, p->one);
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		textconv_two = get_textconv(o->repo, p->two);
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	}
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	/*
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	 * If we have an unmodified pair, we know that the count will be the
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	 * same and don't even have to load the blobs. Unless textconv is in
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	 * play, _and_ we are using two different textconv filters (e.g.,
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	 * because a pair is an exact rename with different textconv attributes
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	 * for each side, which might generate different content).
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	 */
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	if (textconv_one == textconv_two && diff_unmodified_pair(p))
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		return 0;
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	if ((o->pickaxe_opts & DIFF_PICKAXE_KIND_G) &&
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	    !o->flags.text &&
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	    ((!textconv_one && diff_filespec_is_binary(o->repo, p->one)) ||
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	     (!textconv_two && diff_filespec_is_binary(o->repo, p->two))))
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		return 0;
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	mf1.size = fill_textconv(o->repo, textconv_one, p->one, &mf1.ptr);
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	mf2.size = fill_textconv(o->repo, textconv_two, p->two, &mf2.ptr);
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	ret = fn(&mf1, &mf2, o, regexp, kws);
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	if (textconv_one)
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		free(mf1.ptr);
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	if (textconv_two)
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		free(mf2.ptr);
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	diff_free_filespec_data(p->one);
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	diff_free_filespec_data(p->two);
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	return ret;
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}
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static void pickaxe(struct diff_queue_struct *q, struct diff_options *o,
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		    regex_t *regexp, kwset_t kws, pickaxe_fn fn)
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{
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	int i;
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	struct diff_queue_struct outq;
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	DIFF_QUEUE_CLEAR(&outq);
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	if (o->pickaxe_opts & DIFF_PICKAXE_ALL) {
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		/* Showing the whole changeset if needle exists */
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		for (i = 0; i < q->nr; i++) {
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			struct diff_filepair *p = q->queue[i];
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			if (pickaxe_match(p, o, regexp, kws, fn))
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				return; /* do not munge the queue */
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		}
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		/*
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		 * Otherwise we will clear the whole queue by copying
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		 * the empty outq at the end of this function, but
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		 * first clear the current entries in the queue.
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		 */
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		for (i = 0; i < q->nr; i++)
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			diff_free_filepair(q->queue[i]);
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	} else {
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		/* Showing only the filepairs that has the needle */
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		for (i = 0; i < q->nr; i++) {
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			struct diff_filepair *p = q->queue[i];
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			if (pickaxe_match(p, o, regexp, kws, fn))
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				diff_q(&outq, p);
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			else
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				diff_free_filepair(p);
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		}
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	}
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	free(q->queue);
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	*q = outq;
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}
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static void regcomp_or_die(regex_t *regex, const char *needle, int cflags)
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{
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	int err = regcomp(regex, needle, cflags);
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	if (err) {
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		/* The POSIX.2 people are surely sick */
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		char errbuf[1024];
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		regerror(err, regex, errbuf, 1024);
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		die("invalid regex: %s", errbuf);
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	}
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}
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void diffcore_pickaxe(struct diff_options *o)
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{
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	const char *needle = o->pickaxe;
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	int opts = o->pickaxe_opts;
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	regex_t regex, *regexp = NULL;
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	kwset_t kws = NULL;
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	pickaxe_fn fn;
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	if (opts & ~DIFF_PICKAXE_KIND_OBJFIND &&
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	    (!needle || !*needle))
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		BUG("should have needle under -G or -S");
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	if (opts & (DIFF_PICKAXE_REGEX | DIFF_PICKAXE_KIND_G)) {
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		int cflags = REG_EXTENDED | REG_NEWLINE;
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		if (o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE)
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			cflags |= REG_ICASE;
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		regcomp_or_die(&regex, needle, cflags);
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		regexp = &regex;
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		if (opts & DIFF_PICKAXE_KIND_G)
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			fn = diff_grep;
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		else if (opts & DIFF_PICKAXE_REGEX)
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			fn = has_changes;
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		else
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			/*
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			 * We don't need to check the combination of
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			 * -G and --pickaxe-regex, by the time we get
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			 * here diff.c has already died if they're
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			 * combined. See the usage tests in
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			 * t4209-log-pickaxe.sh.
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			 */
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			BUG("unreachable");
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	} else if (opts & DIFF_PICKAXE_KIND_S) {
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		if (o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE &&
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		    has_non_ascii(needle)) {
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			struct strbuf sb = STRBUF_INIT;
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			int cflags = REG_NEWLINE | REG_ICASE;
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			basic_regex_quote_buf(&sb, needle);
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			regcomp_or_die(&regex, sb.buf, cflags);
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			strbuf_release(&sb);
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			regexp = &regex;
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		} else {
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			kws = kwsalloc(o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE
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				       ? tolower_trans_tbl : NULL);
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			kwsincr(kws, needle, strlen(needle));
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			kwsprep(kws);
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		}
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		fn = has_changes;
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	} else if (opts & DIFF_PICKAXE_KIND_OBJFIND) {
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		fn = NULL;
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	} else {
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		BUG("unknown pickaxe_opts flag");
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	}
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	pickaxe(&diff_queued_diff, o, regexp, kws, fn);
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	if (regexp)
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		regfree(regexp);
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	if (kws)
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		kwsfree(kws);
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	return;
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}
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