[PATCH v4 1/2] compat: add a mkstemps() compatibility function

[PATCH v4 1/2] compat: add a mkstemps() compatibility function

[David Aguilar]

mkstemps() is a BSD extension so provide an implementation
for cross-platform use.

Signed-off-by: David Aguilar <davvid@gmail.com>
Tested-by: Johannes Sixt <j6t@kdbg.org> (Windows)
---

This patch is unchanged from last time.
I'm including it here for completeness.

 Makefile          |   19 +++++++++++++++
 compat/mkstemps.c |   67 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 config.mak.in     |    1 +
 configure.ac      |    6 ++++
 git-compat-util.h |    5 ++++
 5 files changed, 98 insertions(+), 0 deletions(-)
 create mode 100644 compat/mkstemps.c

diff --git a/Makefile b/Makefile
index eaae45d..a70b5f0 100644
--- a/Makefile
+++ b/Makefile
@@ -52,6 +52,8 @@ all::
 #
 # Define NO_MKDTEMP if you don't have mkdtemp in the C library.
 #
+# Define NO_MKSTEMPS if you don't have mkstemps in the C library.
+#
 # Define NO_SYS_SELECT_H if you don't have sys/select.h.
 #
 # Define NO_SYMLINK_HEAD if you never want .git/HEAD to be a symbolic link.
@@ -636,10 +638,12 @@ EXTLIBS =
 
 ifeq ($(uname_S),Linux)
 	NO_STRLCPY = YesPlease
+	NO_MKSTEMPS = YesPlease
 	THREADED_DELTA_SEARCH = YesPlease
 endif
 ifeq ($(uname_S),GNU/kFreeBSD)
 	NO_STRLCPY = YesPlease
+	NO_MKSTEMPS = YesPlease
 	THREADED_DELTA_SEARCH = YesPlease
 endif
 ifeq ($(uname_S),UnixWare)
@@ -651,6 +655,7 @@ ifeq ($(uname_S),UnixWare)
 	SHELL_PATH = /usr/local/bin/bash
 	NO_IPV6 = YesPlease
 	NO_HSTRERROR = YesPlease
+	NO_MKSTEMPS = YesPlease
 	BASIC_CFLAGS += -Kthread
 	BASIC_CFLAGS += -I/usr/local/include
 	BASIC_LDFLAGS += -L/usr/local/lib
@@ -674,6 +679,7 @@ ifeq ($(uname_S),SCO_SV)
 	SHELL_PATH = /usr/bin/bash
 	NO_IPV6 = YesPlease
 	NO_HSTRERROR = YesPlease
+	NO_MKSTEMPS = YesPlease
 	BASIC_CFLAGS += -I/usr/local/include
 	BASIC_LDFLAGS += -L/usr/local/lib
 	NO_STRCASESTR = YesPlease
@@ -702,6 +708,7 @@ ifeq ($(uname_S),SunOS)
 	NO_MEMMEM = YesPlease
 	NO_HSTRERROR = YesPlease
 	NO_MKDTEMP = YesPlease
+	NO_MKSTEMPS = YesPlease
 	OLD_ICONV = UnfortunatelyYes
 	ifeq ($(uname_R),5.8)
 		NO_UNSETENV = YesPlease
@@ -724,6 +731,7 @@ ifeq ($(uname_O),Cygwin)
 	NO_D_INO_IN_DIRENT = YesPlease
 	NO_STRCASESTR = YesPlease
 	NO_MEMMEM = YesPlease
+	NO_MKSTEMPS = YesPlease
 	NO_SYMLINK_HEAD = YesPlease
 	NEEDS_LIBICONV = YesPlease
 	NO_FAST_WORKING_DIRECTORY = UnfortunatelyYes
@@ -767,11 +775,13 @@ ifeq ($(uname_S),NetBSD)
 	BASIC_LDFLAGS += -L/usr/pkg/lib $(CC_LD_DYNPATH)/usr/pkg/lib
 	THREADED_DELTA_SEARCH = YesPlease
 	USE_ST_TIMESPEC = YesPlease
+	NO_MKSTEMPS = YesPlease
 endif
 ifeq ($(uname_S),AIX)
 	NO_STRCASESTR=YesPlease
 	NO_MEMMEM = YesPlease
 	NO_MKDTEMP = YesPlease
+	NO_MKSTEMPS = YesPlease
 	NO_STRLCPY = YesPlease
 	NO_NSEC = YesPlease
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
@@ -787,12 +797,14 @@ endif
 ifeq ($(uname_S),GNU)
 	# GNU/Hurd
 	NO_STRLCPY=YesPlease
+	NO_MKSTEMPS = YesPlease
 endif
 ifeq ($(uname_S),IRIX64)
 	NO_IPV6=YesPlease
 	NO_SETENV=YesPlease
 	NO_STRCASESTR=YesPlease
 	NO_MEMMEM = YesPlease
+	NO_MKSTEMPS = YesPlease
 	NO_STRLCPY = YesPlease
 	NO_SOCKADDR_STORAGE=YesPlease
 	SHELL_PATH=/usr/gnu/bin/bash
@@ -805,6 +817,7 @@ ifeq ($(uname_S),HP-UX)
 	NO_SETENV=YesPlease
 	NO_STRCASESTR=YesPlease
 	NO_MEMMEM = YesPlease
+	NO_MKSTEMPS = YesPlease
 	NO_STRLCPY = YesPlease
 	NO_MKDTEMP = YesPlease
 	NO_UNSETENV = YesPlease
@@ -834,6 +847,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_C99_FORMAT = YesPlease
 	NO_STRTOUMAX = YesPlease
 	NO_MKDTEMP = YesPlease
+	NO_MKSTEMPS = YesPlease
 	SNPRINTF_RETURNS_BOGUS = YesPlease
 	NO_SVN_TESTS = YesPlease
 	NO_PERL_MAKEMAKER = YesPlease
@@ -853,6 +867,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 endif
 ifneq (,$(findstring arm,$(uname_M)))
 	ARM_SHA1 = YesPlease
+	NO_MKSTEMPS = YesPlease
 endif
 
 -include config.mak.autogen
@@ -1011,6 +1026,10 @@ ifdef NO_MKDTEMP
 	COMPAT_CFLAGS += -DNO_MKDTEMP
 	COMPAT_OBJS += compat/mkdtemp.o
 endif
+ifdef NO_MKSTEMPS
+	COMPAT_CFLAGS += -DNO_MKSTEMPS
+	COMPAT_OBJS += compat/mkstemps.o
+endif
 ifdef NO_UNSETENV
 	COMPAT_CFLAGS += -DNO_UNSETENV
 	COMPAT_OBJS += compat/unsetenv.o
diff --git a/compat/mkstemps.c b/compat/mkstemps.c
new file mode 100644
index 0000000..87ebc2a
--- /dev/null
+++ b/compat/mkstemps.c
@@ -0,0 +1,67 @@
+#include "../git-compat-util.h"
+
+#ifndef TMP_MAX
+#define TMP_MAX 16384
+#endif
+
+/* Adapted from libiberty's mkstemp.c. */
+int gitmkstemps(char *pattern, int suffix_len)
+{
+	static const char letters[] =
+		"abcdefghijklmnopqrstuvwxyz"
+		"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+		"0123456789";
+	static const int num_letters = 62;
+	uint64_t value;
+	struct timeval tv;
+	char *template;
+	size_t len;
+	int fd, count;
+
+	len = strlen(pattern);
+
+	if (len < 6 + suffix_len) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	/* Replace pattern's XXXXXX characters with randomness.
+	 * Try TMP_MAX different filenames.
+	 */
+	gettimeofday(&tv, NULL);
+	value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
+	template = &pattern[len - 6 - suffix_len];
+	for (count = 0; count < TMP_MAX; ++count) {
+		uint64_t v = value;
+		/* Fill in the random bits. */
+		template[0] = letters[v % num_letters]; v/= num_letters;
+		template[1] = letters[v % num_letters]; v/= num_letters;
+		template[2] = letters[v % num_letters]; v/= num_letters;
+		template[3] = letters[v % num_letters]; v/= num_letters;
+		template[4] = letters[v % num_letters]; v/= num_letters;
+		template[5] = letters[v % num_letters]; v/= num_letters;
+
+		fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, 0600);
+		if (fd > 0)
+			return fd;
+		/* Fatal error (EPERM, ENOSPC etc).
+		 * It doesn't make sense to loop.
+		 */
+		if (errno != EEXIST)
+			break;
+		/* This is a random value.  It is only necessary that
+		 * the next TMP_MAX values generated by adding 7777 to
+		 * VALUE are different with (module 2^32).
+		 */
+		value += 7777;
+	}
+	/* We return the null string if we can't find a unique file name.  */
+	pattern[0] = '\0';
+	errno = EINVAL;
+	return -1;
+}
diff --git a/config.mak.in b/config.mak.in
index 7cce0c1..b6619af 100644
--- a/config.mak.in
+++ b/config.mak.in
@@ -46,6 +46,7 @@ NO_STRTOUMAX=@NO_STRTOUMAX@
 NO_SETENV=@NO_SETENV@
 NO_UNSETENV=@NO_UNSETENV@
 NO_MKDTEMP=@NO_MKDTEMP@
+NO_MKSTEMPS=@NO_MKSTEMPS@
 NO_ICONV=@NO_ICONV@
 OLD_ICONV=@OLD_ICONV@
 NO_DEFLATE_BOUND=@NO_DEFLATE_BOUND@
diff --git a/configure.ac b/configure.ac
index 4e728bc..95dccd4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -676,6 +676,12 @@ GIT_CHECK_FUNC(mkdtemp,
 [NO_MKDTEMP=],
 [NO_MKDTEMP=YesPlease])
 AC_SUBST(NO_MKDTEMP)
+# Define NO_MKSTEMPS if you don't have mkstemps in the C library.
+GIT_CHECK_FUNC(mkstemps,
+[NO_MKSTEMPS=],
+[NO_MKSTEMPS=YesPlease])
+AC_SUBST(NO_MKSTEMPS)
+#
 #
 # Define NO_MMAP if you want to avoid mmap.
 #
diff --git a/git-compat-util.h b/git-compat-util.h
index c7cf2d5..f7217ad 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -232,6 +232,11 @@ extern int gitsetenv(const char *, const char *, int);
 extern char *gitmkdtemp(char *);
 #endif
 
+#ifdef NO_MKSTEMPS
+#define mkstemps gitmkstemps
+extern int gitmkstemps(char *, int);
+#endif
+
 #ifdef NO_UNSETENV
 #define unsetenv gitunsetenv
 extern void gitunsetenv(const char *);
-- 
1.6.1.3

[PATCH v4 2/2] diff: generate pretty filenames in prep_temp_blob()

[David Aguilar]

Naturally, prep_temp_blob() did not care about filenames.
As a result, scripts that used GIT_EXTERNAL_DIFF or textconv
ended up with filenames such as ".diff_XXXXXX".

This modifies prep_temp_blob() to generate user-friendly
filenames when creating temporary files.

Diffing "name.ext" now generates "XXXXXX_name.ext".

Signed-off-by: David Aguilar <davvid@gmail.com>
Tested-by: Johannes Sixt <j6t@kdbg.org> (Windows)
---

This includes Peff's suggestion to make this the
default behavior.

Peff mentioned that: "Switching to user-friendly
temp filenames for textconv was on my todo list".

This patch accomplishes exactly that for both
textconv and GIT_EXTERNAL_DIFF.

 cache.h                  |    2 ++
 diff.c                   |   19 ++++++++++++++++++-
 path.c                   |   16 ++++++++++++++++
 t/t4020-diff-external.sh |    9 +++++++++
 4 files changed, 45 insertions(+), 1 deletions(-)

diff --git a/cache.h b/cache.h
index b8503ad..871c984 100644
--- a/cache.h
+++ b/cache.h
@@ -614,6 +614,8 @@ extern int is_empty_blob_sha1(const unsigned char *sha1);
 
 int git_mkstemp(char *path, size_t n, const char *template);
 
+int git_mkstemps(char *path, size_t n, const char *template, int suffix_len);
+
 /*
  * NOTE NOTE NOTE!!
  *
diff --git a/diff.c b/diff.c
index dcfbcb0..85503ce 100644
--- a/diff.c
+++ b/diff.c
@@ -1964,8 +1964,24 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
 {
 	int fd;
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf template = STRBUF_INIT;
+	char *basename = ((char*)path) + strlen(path) - 1;
+
+	/* Windows lacks basename() */
+	while(*basename && basename > path) {
+		basename--;
+		if (is_dir_sep(*basename)) {
+			basename++;
+			break;
+		}
+	}
+
+	/* Generate "XXXXXX_basename.ext" */
+	strbuf_addstr(&template, "XXXXXX_");
+	strbuf_addstr(&template, basename);
 
-	fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
+	fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
+			strlen(basename) + 1);
 	if (fd < 0)
 		die("unable to create temp-file: %s", strerror(errno));
 	if (convert_to_working_tree(path,
@@ -1981,6 +1997,7 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
 	temp->hex[40] = 0;
 	sprintf(temp->mode, "%06o", mode);
 	strbuf_release(&buf);
+	strbuf_release(&template);
 }
 
 static struct diff_tempfile *prepare_temp_file(const char *name,
diff --git a/path.c b/path.c
index 8a0a674..047fdb0 100644
--- a/path.c
+++ b/path.c
@@ -139,6 +139,22 @@ int git_mkstemp(char *path, size_t len, const char *template)
 	return mkstemp(path);
 }
 
+/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
+int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
+{
+	const char *tmp;
+	size_t n;
+
+	tmp = getenv("TMPDIR");
+	if (!tmp)
+		tmp = "/tmp";
+	n = snprintf(path, len, "%s/%s", tmp, template);
+	if (len <= n) {
+		errno = ENAMETOOLONG;
+		return -1;
+	}
+	return mkstemps(path, suffix_len);
+}
 
 int validate_headref(const char *path)
 {
diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index 0720001..4ea42e0 100755
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -136,6 +136,15 @@ test_expect_success 'GIT_EXTERNAL_DIFF with more than one changed files' '
 	GIT_EXTERNAL_DIFF=echo git diff
 '
 
+test_expect_success 'GIT_EXTERNAL_DIFF generates pretty paths' '
+	touch file.ext &&
+	git add file.ext &&
+	echo with extension > file.ext &&
+	GIT_EXTERNAL_DIFF=echo git diff file.ext | grep ......_file\.ext &&
+	git update-index --force-remove file.ext &&
+	rm file.ext
+'
+
 echo "#!$SHELL_PATH" >fake-diff.sh
 cat >> fake-diff.sh <<\EOF
 cat $2 >> crlfed.txt
-- 
1.6.1.3

Re: [PATCH v4 2/2] diff: generate pretty filenames in prep_temp_blob()

[Jeff King]

On Thu, May 28, 2009 at 05:49:24PM -0700, David Aguilar wrote:

> @@ -1964,8 +1964,24 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
>  {
>  	int fd;
>  	struct strbuf buf = STRBUF_INIT;
> +	struct strbuf template = STRBUF_INIT;
> +	char *basename = ((char*)path) + strlen(path) - 1;

Why do you drop constness in this assignment?

> +	/* Windows lacks basename() */
> +	while(*basename && basename > path) {
> +		basename--;
> +		if (is_dir_sep(*basename)) {
> +			basename++;
> +			break;
> +		}
> +	}

This is such an easily-factorable bit, maybe it makes sense to add as
basename() in compat/?

-Peff

Re: [PATCH v4 2/2] diff: generate pretty filenames in prep_temp_blob()

[David Aguilar]

On Fri, May 29, 2009 at 03:55:37PM -0400, Jeff King wrote:
> On Thu, May 28, 2009 at 05:49:24PM -0700, David Aguilar wrote:
> 
> > @@ -1964,8 +1964,24 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
> >  {
> >  	int fd;
> >  	struct strbuf buf = STRBUF_INIT;
> > +	struct strbuf template = STRBUF_INIT;
> > +	char *basename = ((char*)path) + strlen(path) - 1;
> 
> Why do you drop constness in this assignment?


That was a mistake.


> > +	/* Windows lacks basename() */
> > +	while(*basename && basename > path) {
> > +		basename--;
> > +		if (is_dir_sep(*basename)) {
> > +			basename++;
> > +			break;
> > +		}
> > +	}
> 
> This is such an easily-factorable bit, maybe it makes sense to add as
> basename() in compat/?

I would feel a little better calling it
git_basename(const char *) and keeping it in path.c
(or another name if basename is no good)

The reason is from the manpage for basename:

"Both dirname() and basename() may modify the
contents of path, so it may be desirable to
pass a copy when calling one of these functions."

The above snippet is much simpler and does not have
that restriction since we can guarantee const-ness.

All this version cares about is being able to find the
last dir_sep and returning a pointer.

What do you think?

-- 

	David

Re: [PATCH v4 2/2] diff: generate pretty filenames in prep_temp_blob()

[Jeff King]

On Fri, May 29, 2009 at 06:22:05PM -0700, David Aguilar wrote:

> > This is such an easily-factorable bit, maybe it makes sense to add as
> > basename() in compat/?
> 
> I would feel a little better calling it
> git_basename(const char *) and keeping it in path.c
> [...]
> All this version cares about is being able to find the
> last dir_sep and returning a pointer.
> 
> What do you think?

That sounds good to me.

-Peff