From dcb191a29ea75d9a49351fdf5abbbf37bdcea4bd Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Thu, 20 Jul 2017 15:27:39 -0300
Subject: [PATCH 131/132] tools include: Adopt strstarts() from the kernel

[tonyj: move tools/perf change to perf package]

Git-commit: 8e99b6d4533cf3f49dcd813155a513a5b572baef
Patch-mainline: v4.14-rc1
References: fate#325865,fate#325861

Replacing prefixcmp(), same purpose, inverted result, so standardize on
the kernel variant, to reduce silly differences among tools/ and the
kernel sources, making it easier for people to work in both codebases.

And then doing:

	if (strstarts(option, "no-"))

Looks clearer than doing:

	if (!prefixcmp(option, "no-"))

To figure out if option starts witn "no-".

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-kaei42gi7lpa8subwtv7eug8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 tools/include/linux/string.h     |   12 ++++++++++--
 tools/lib/string.c               |    9 ---------
 tools/lib/subcmd/help.c          |    2 +-
 tools/lib/subcmd/parse-options.c |   18 +++++++++---------
 4 files changed, 20 insertions(+), 21 deletions(-)

--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -1,8 +1,8 @@
 #ifndef _TOOLS_LINUX_STRING_H_
 #define _TOOLS_LINUX_STRING_H_
 
-
 #include <linux/types.h>	/* for size_t */
+#include <string.h>
 
 void *memdup(const void *src, size_t len);
 
@@ -18,6 +18,14 @@ extern size_t strlcpy(char *dest, const
 
 char *str_error_r(int errnum, char *buf, size_t buflen);
 
-int prefixcmp(const char *str, const char *prefix);
+/**
+ * strstarts - does @str start with @prefix?
+ * @str: string to examine
+ * @prefix: prefix to look for.
+ */
+static inline bool strstarts(const char *str, const char *prefix)
+{
+	return strncmp(str, prefix, strlen(prefix)) == 0;
+}
 
 #endif /* _LINUX_STRING_H_ */
--- a/tools/lib/string.c
+++ b/tools/lib/string.c
@@ -87,12 +87,3 @@ size_t __weak strlcpy(char *dest, const
 	}
 	return ret;
 }
-
-int prefixcmp(const char *str, const char *prefix)
-{
-	for (; ; str++, prefix++)
-		if (!*prefix)
-			return 0;
-		else if (*str != *prefix)
-			return (unsigned char)*prefix - (unsigned char)*str;
-}
--- a/tools/lib/subcmd/help.c
+++ b/tools/lib/subcmd/help.c
@@ -171,7 +171,7 @@ static void list_commands_in_dir(struct
 	while ((de = readdir(dir)) != NULL) {
 		int entlen;
 
-		if (prefixcmp(de->d_name, prefix))
+		if (!strstarts(de->d_name, prefix))
 			continue;
 
 		astrcat(&buf, de->d_name);
--- a/tools/lib/subcmd/parse-options.c
+++ b/tools/lib/subcmd/parse-options.c
@@ -368,7 +368,7 @@ retry:
 			return 0;
 		}
 		if (!rest) {
-			if (!prefixcmp(options->long_name, "no-")) {
+			if (strstarts(options->long_name, "no-")) {
 				/*
 				 * The long name itself starts with "no-", so
 				 * accept the option without "no-" so that users
@@ -381,7 +381,7 @@ retry:
 					goto match;
 				}
 				/* Abbreviated case */
-				if (!prefixcmp(options->long_name + 3, arg)) {
+				if (strstarts(options->long_name + 3, arg)) {
 					flags |= OPT_UNSET;
 					goto is_abbreviated;
 				}
@@ -406,7 +406,7 @@ is_abbreviated:
 				continue;
 			}
 			/* negated and abbreviated very much? */
-			if (!prefixcmp("no-", arg)) {
+			if (strstarts("no-", arg)) {
 				flags |= OPT_UNSET;
 				goto is_abbreviated;
 			}
@@ -416,7 +416,7 @@ is_abbreviated:
 			flags |= OPT_UNSET;
 			rest = skip_prefix(arg + 3, options->long_name);
 			/* abbreviated and negated? */
-			if (!rest && !prefixcmp(options->long_name, arg + 3))
+			if (!rest && strstarts(options->long_name, arg + 3))
 				goto is_abbreviated;
 			if (!rest)
 				continue;
@@ -456,7 +456,7 @@ static void check_typos(const char *arg,
 	if (strlen(arg) < 3)
 		return;
 
-	if (!prefixcmp(arg, "no-")) {
+	if (strstarts(arg, "no-")) {
 		fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)", arg);
 		exit(129);
 	}
@@ -464,7 +464,7 @@ static void check_typos(const char *arg,
 	for (; options->type != OPTION_END; options++) {
 		if (!options->long_name)
 			continue;
-		if (!prefixcmp(options->long_name, arg)) {
+		if (strstarts(options->long_name, arg)) {
 			fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)", arg);
 			exit(129);
 		}
@@ -933,10 +933,10 @@ opt:
 		if (opts->long_name == NULL)
 			continue;
 
-		if (!prefixcmp(opts->long_name, optstr))
+		if (strstarts(opts->long_name, optstr))
 			print_option_help(opts, 0);
-		if (!prefixcmp("no-", optstr) &&
-		    !prefixcmp(opts->long_name, optstr + 3))
+		if (strstarts("no-", optstr) &&
+		    strstarts(opts->long_name, optstr + 3))
 			print_option_help(opts, 0);
 	}