Merge branch 'nd/icase' into maint

"git grep -i" has been taught to fold case in non-ascii locales
correctly.

* nd/icase:
  grep.c: reuse "icase" variable
  diffcore-pickaxe: support case insensitive match on non-ascii
  diffcore-pickaxe: Add regcomp_or_die()
  grep/pcre: support utf-8
  gettext: add is_utf8_locale()
  grep/pcre: prepare locale-dependent tables for icase matching
  grep: rewrite an if/else condition to avoid duplicate expression
  grep/icase: avoid kwsset when -F is specified
  grep/icase: avoid kwsset on literal non-ascii strings
  test-regex: expose full regcomp() to the command line
  test-regex: isolate the bug test code
  grep: break down an "if" stmt in preparation for next changes

Author: gitster

diffcore-pickaxe.c

@@ -7,6 +7,8 @@
 #include "diffcore.h"
 #include "xdiff-interface.h"
 #include "kwset.h"
+#include "commit.h"
+#include "quote.h"
 
 typedef int (*pickaxe_fn)(mmfile_t *one, mmfile_t *two,
 			  struct diff_options *o,
@@ -198,6 +200,18 @@ static void pickaxe(struct diff_queue_struct *q, struct diff_options *o,
 	*q = outq;
 }
 
+static void regcomp_or_die(regex_t *regex, const char *needle, int cflags)
+{
+	int err = regcomp(regex, needle, cflags);
+	if (err) {
+		/* The POSIX.2 people are surely sick */
+		char errbuf[1024];
+		regerror(err, regex, errbuf, 1024);
+		regfree(regex);
+		die("invalid regex: %s", errbuf);
+	}
+}
+
 void diffcore_pickaxe(struct diff_options *o)
 {
 	const char *needle = o->pickaxe;
@@ -206,18 +220,19 @@ void diffcore_pickaxe(struct diff_options *o)
 	kwset_t kws = NULL;
 
 	if (opts & (DIFF_PICKAXE_REGEX | DIFF_PICKAXE_KIND_G)) {
-		int err;
 		int cflags = REG_EXTENDED | REG_NEWLINE;
 		if (DIFF_OPT_TST(o, PICKAXE_IGNORE_CASE))
 			cflags |= REG_ICASE;
-		err = regcomp(&regex, needle, cflags);
-		if (err) {
-			/* The POSIX.2 people are surely sick */
-			char errbuf[1024];
-			regerror(err, &regex, errbuf, 1024);
-			regfree(&regex);
-			die("invalid regex: %s", errbuf);
-		}
+		regcomp_or_die(&regex, needle, cflags);
+		regexp = &regex;
+	} else if (DIFF_OPT_TST(o, PICKAXE_IGNORE_CASE) &&
+		   has_non_ascii(needle)) {
+		struct strbuf sb = STRBUF_INIT;
+		int cflags = REG_NEWLINE | REG_ICASE;
+
+		basic_regex_quote_buf(&sb, needle);
+		regcomp_or_die(&regex, sb.buf, cflags);
+		strbuf_release(&sb);
 		regexp = &regex;
 	} else {
 		kws = kwsalloc(DIFF_OPT_TST(o, PICKAXE_IGNORE_CASE)

gettext.c

@@ -18,6 +18,8 @@
 #	endif
 #endif
 
+static const char *charset;
+
 /*
  * Guess the user's preferred languages from the value in LANGUAGE environment
  * variable and LC_MESSAGES locale category if NO_GETTEXT is not defined.
@@ -65,7 +67,6 @@ static int test_vsnprintf(const char *fmt, ...)
 	return ret;
 }
 
-static const char *charset;
 static void init_gettext_charset(const char *domain)
 {
 	/*
@@ -172,8 +173,27 @@ int gettext_width(const char *s)
 {
 	static int is_utf8 = -1;
 	if (is_utf8 == -1)
-		is_utf8 = !strcmp(charset, "UTF-8");
+		is_utf8 = is_utf8_locale();
 
 	return is_utf8 ? utf8_strwidth(s) : strlen(s);
 }
 #endif
+
+int is_utf8_locale(void)
+{
+#ifdef NO_GETTEXT
+	if (!charset) {
+		const char *env = getenv("LC_ALL");
+		if (!env || !*env)
+			env = getenv("LC_CTYPE");
+		if (!env || !*env)
+			env = getenv("LANG");
+		if (!env)
+			env = "";
+		if (strchr(env, '.'))
+			env = strchr(env, '.') + 1;
+		charset = xstrdup(env);
+	}
+#endif
+	return is_encoding_utf8(charset);
+}

gettext.h

@@ -90,5 +90,6 @@ const char *Q_(const char *msgid, const char *plu, unsigned long n)
 #endif
 
 const char *get_preferred_languages(void);
+extern int is_utf8_locale(void);
 
 #endif

grep.c

@@ -4,6 +4,8 @@
 #include "xdiff-interface.h"
 #include "diff.h"
 #include "diffcore.h"
+#include "commit.h"
+#include "quote.h"
 
 static int grep_source_load(struct grep_source *gs);
 static int grep_source_is_binary(struct grep_source *gs);
@@ -322,11 +324,16 @@ static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 	int erroffset;
 	int options = PCRE_MULTILINE;
 
-	if (opt->ignore_case)
+	if (opt->ignore_case) {
+		if (has_non_ascii(p->pattern))
+			p->pcre_tables = pcre_maketables();
 		options |= PCRE_CASELESS;
+	}
+	if (is_utf8_locale() && has_non_ascii(p->pattern))
+		options |= PCRE_UTF8;
 
 	p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
-			NULL);
+				      p->pcre_tables);
 	if (!p->pcre_regexp)
 		compile_regexp_failed(p, error);
 
@@ -360,6 +367,7 @@ static void free_pcre_regexp(struct grep_pat *p)
 {
 	pcre_free(p->pcre_regexp);
 	pcre_free(p->pcre_extra_info);
+	pcre_free((void *)p->pcre_tables);
 }
 #else /* !USE_LIBPCRE */
 static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
@@ -396,26 +404,68 @@ static int is_fixed(const char *s, size_t len)
 	return 1;
 }
 
+static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int err;
+	int regflags;
+
+	basic_regex_quote_buf(&sb, p->pattern);
+	regflags = opt->regflags & ~REG_EXTENDED;
+	if (opt->ignore_case)
+		regflags |= REG_ICASE;
+	err = regcomp(&p->regexp, sb.buf, regflags);
+	if (opt->debug)
+		fprintf(stderr, "fixed %s\n", sb.buf);
+	strbuf_release(&sb);
+	if (err) {
+		char errbuf[1024];
+		regerror(err, &p->regexp, errbuf, sizeof(errbuf));
+		regfree(&p->regexp);
+		compile_regexp_failed(p, errbuf);
+	}
+}
+
 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 {
+	int icase, ascii_only;
 	int err;
 
 	p->word_regexp = opt->word_regexp;
 	p->ignore_case = opt->ignore_case;
+	icase	       = opt->regflags & REG_ICASE || p->ignore_case;
+	ascii_only     = !has_non_ascii(p->pattern);
 
+	/*
+	 * Even when -F (fixed) asks us to do a non-regexp search, we
+	 * may not be able to correctly case-fold when -i
+	 * (ignore-case) is asked (in which case, we'll synthesize a
+	 * regexp to match the pattern that matches regexp special
+	 * characters literally, while ignoring case differences).  On
+	 * the other hand, even without -F, if the pattern does not
+	 * have any regexp special characters and there is no need for
+	 * case-folding search, we can internally turn it into a
+	 * simple string match using kws.  p->fixed tells us if we
+	 * want to use kws.
+	 */
 	if (opt->fixed || is_fixed(p->pattern, p->patternlen))
-		p->fixed = 1;
+		p->fixed = !icase || ascii_only;
 	else
 		p->fixed = 0;
 
 	if (p->fixed) {
-		if (opt->regflags & REG_ICASE || p->ignore_case)
-			p->kws = kwsalloc(tolower_trans_tbl);
-		else
-			p->kws = kwsalloc(NULL);
+		p->kws = kwsalloc(icase ? tolower_trans_tbl : NULL);
 		kwsincr(p->kws, p->pattern, p->patternlen);
 		kwsprep(p->kws);
 		return;
+	} else if (opt->fixed) {
+		/*
+		 * We come here when the pattern has the non-ascii
+		 * characters we cannot case-fold, and asked to
+		 * ignore-case.
+		 */
+		compile_fixed_regexp(p, opt);
+		return;
 	}
 
 	if (opt->pcre) {

grep.h

@@ -48,6 +48,7 @@ struct grep_pat {
 	regex_t regexp;
 	pcre *pcre_regexp;
 	pcre_extra *pcre_extra_info;
+	const unsigned char *pcre_tables;
 	kwset_t kws;
 	unsigned fixed:1;
 	unsigned ignore_case:1;

quote.c

@@ -453,3 +453,40 @@ void tcl_quote_buf(struct strbuf *sb, const char *src)
 	}
 	strbuf_addch(sb, '"');
 }
+
+void basic_regex_quote_buf(struct strbuf *sb, const char *src)
+{
+	char c;
+
+	if (*src == '^') {
+		/* only beginning '^' is special and needs quoting */
+		strbuf_addch(sb, '\\');
+		strbuf_addch(sb, *src++);
+	}
+	if (*src == '*')
+		/* beginning '*' is not special, no quoting */
+		strbuf_addch(sb, *src++);
+
+	while ((c = *src++)) {
+		switch (c) {
+		case '[':
+		case '.':
+		case '\\':
+		case '*':
+			strbuf_addch(sb, '\\');
+			strbuf_addch(sb, c);
+			break;
+
+		case '$':
+			/* only the end '$' is special and needs quoting */
+			if (*src == '\0')
+				strbuf_addch(sb, '\\');
+			strbuf_addch(sb, c);
+			break;
+
+		default:
+			strbuf_addch(sb, c);
+			break;
+		}
+	}
+}

quote.h

@@ -70,5 +70,6 @@ extern char *quote_path_relative(const char *in, const char *prefix,
 extern void perl_quote_buf(struct strbuf *sb, const char *src);
 extern void python_quote_buf(struct strbuf *sb, const char *src);
 extern void tcl_quote_buf(struct strbuf *sb, const char *src);
+extern void basic_regex_quote_buf(struct strbuf *sb, const char *src);
 
 #endif

t/helper/test-regex.c

@@ -1,6 +1,23 @@
 #include "git-compat-util.h"
+#include "gettext.h"
 
-int main(int argc, char **argv)
+struct reg_flag {
+	const char *name;
+	int flag;
+};
+
+static struct reg_flag reg_flags[] = {
+	{ "EXTENDED",	 REG_EXTENDED	},
+	{ "NEWLINE",	 REG_NEWLINE	},
+	{ "ICASE",	 REG_ICASE	},
+	{ "NOTBOL",	 REG_NOTBOL	},
+#ifdef REG_STARTEND
+	{ "STARTEND",	 REG_STARTEND	},
+#endif
+	{ NULL, 0 }
+};
+
+static int test_regex_bug(void)
 {
 	char *pat = "[^={} \t]+";
 	char *str = "={}\nfred";
@@ -16,5 +33,43 @@ int main(int argc, char **argv)
 	if (m[0].rm_so == 3) /* matches '\n' when it should not */
 		die("regex bug confirmed: re-build git with NO_REGEX=1");
 
-	exit(0);
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	const char *pat;
+	const char *str;
+	int flags = 0;
+	regex_t r;
+	regmatch_t m[1];
+
+	if (argc == 2 && !strcmp(argv[1], "--bug"))
+		return test_regex_bug();
+	else if (argc < 3)
+		usage("test-regex --bug\n"
+		      "test-regex <pattern> <string> [<options>]");
+
+	argv++;
+	pat = *argv++;
+	str = *argv++;
+	while (*argv) {
+		struct reg_flag *rf;
+		for (rf = reg_flags; rf->name; rf++)
+			if (!strcmp(*argv, rf->name)) {
+				flags |= rf->flag;
+				break;
+			}
+		if (!rf->name)
+			die("do not recognize %s", *argv);
+		argv++;
+	}
+	git_setup_gettext();
+
+	if (regcomp(&r, pat, flags))
+		die("failed regcomp() for pattern '%s'", pat);
+	if (regexec(&r, str, 1, m, 0))
+		return 1;
+
+	return 0;
 }

t/t0070-fundamental.sh

@@ -31,7 +31,7 @@ test_expect_success 'git_mkstemps_mode does not fail if fd 0 is not open' '
 
 test_expect_success 'check for a bug in the regex routines' '
 	# if this test fails, re-build git with NO_REGEX=1
-	test-regex
+	test-regex --bug
 '
 
 test_done