Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-19 Thread Jiang Xin 
2013/9/18 Johannes Sixt j...@kdbg.org:
 Am 17.09.2013 10:24, schrieb Jiang Xin:
 I have checked the behavior of UNC path on Windows (msysGit):

 * I can cd to a UNC path:

 cd //server1/share1/path

 * can cd to other share:

 cd ../../share2/path

 * and can cd to other server's share:

 cd ../../../server2/share/path

 That means relative_path(path1, path2) support UNC paths out of the box.
 We only need to check both path1 and path2 are UNC paths, or both not.

 Your tests are flawed. You issued the commands in bash, which (or rather
 MSYS) does everything for you that you need to make it work. But in
 reality it does not, because the system cannot apply .. to //server/share:

 $ git ls-remote //srv/public/../repos/his/setups.git
 fatal: '//srv/public/../repos/his/setups.git' does not appear to be a
 git repository
 fatal: Could not read from remote repository.

 Please make sure you have the correct access rights
 and the repository exists.

 even though the repository (and //srv/public, let me assure) exists:

 $ git ls-remote //srv/repos/his/setups.git
 bea489b0611a72c41f133343fdccbd3e2b9f80b5HEAD
 ...

After see this link (provided by Torsten):


http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx

I find the following commands could work:

$ git ls-remote //srv/repos/his/setups.git
$ git ls-remote //srv/repos/his/../his/setups.git
$ git ls-remote //?/UNC/srv/repos/his/setups.git
$ git ls-remote //?/UNC/srv/repos/../repos/his/setups.git

But no luck for this one:

$ git ls-remote //srv/repos/../repos/his/setups.git

I trace it using gdb, and find it failed in stat()/mingw_stat() call
of function enter_repo in path.c. But I can not find out why
git ls-remote //?/UNC/srv/repos/../repos/his/setups.git could
work (success in shell, failed in gdb).

 Please let me suggest not to scratch where there is no itch. ;) Your
 round v2 was good enough.

 If you really want to check UNC paths, then you must compare two path
 components after the the double-slash, not just one.


I have already try this (honor two path components after //)
during the reroll for patch v3. But I am not satisfied with it,
and it seems like over-engineered: Rename have_same_root
to get_common_root_prefix_width, and it return -1 for no
same_root found, otherwize return the length of root_prefix_width.

Since restored the default behavior of setup.c in commit (Use
simpler relative_path when set_git_dir), function relative_path
are only used in quote.c and builtin/clean.c, and two paths
provided to relative_path are always (I can not find exception)
relative paths. So no itch exist I think.

-- 
Jiang Xin
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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-18 Thread Torsten Bögershausen 
On 2013-09-17 21.32, Johannes Sixt wrote:
 Am 17.09.2013 10:24, schrieb Jiang Xin:
 I have checked the behavior of UNC path on Windows (msysGit):

 * I can cd to a UNC path:

 cd //server1/share1/path

 * can cd to other share:

 cd ../../share2/path

 * and can cd to other server's share:

 cd ../../../server2/share/path

 That means relative_path(path1, path2) support UNC paths out of the box.
 We only need to check both path1 and path2 are UNC paths, or both not.
 
 Your tests are flawed. You issued the commands in bash, which (or rather
 MSYS) does everything for you that you need to make it work. But in
 reality it does not, because the system cannot apply .. to //server/share:
 
 $ git ls-remote //srv/public/../repos/his/setups.git
 fatal: '//srv/public/../repos/his/setups.git' does not appear to be a
 git repository
 fatal: Could not read from remote repository.
 
 Please make sure you have the correct access rights
 and the repository exists.
 
 even though the repository (and //srv/public, let me assure) exists:
 
 $ git ls-remote //srv/repos/his/setups.git
 bea489b0611a72c41f133343fdccbd3e2b9f80b5HEAD
 ...
 
 The situation does not change with your latest round (v3).
 
 Please let me suggest not to scratch where there is no itch. ;) Your
 round v2 was good enough.
 
 If you really want to check UNC paths, then you must compare two path
 components after the the double-slash, not just one.
 
 Furthermore, you should audit all code that references
 is_absolute_path(), relative_path(), normalize_path_copy(), and possibly
 a few others whether the functions or call sites need improvement.
 That's worth a separate patch.
 
 -- Hannes

I tend to agree here.
The V2 patch fixed a regression.
This should be one commit on its own:
Documentation/SubmittingPatches:
(1) Make separate commits for logically separate changes.

Fixing a bug is a good thing, thanks for working on this,

The support for UNC paths is a new feature, and this deserves a seperate commit.
/Torsten





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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-17 Thread Jiang Xin 
2013/9/13 Junio C Hamano gits...@pobox.com:
 Jiang Xin worldhello@gmail.com writes:

 2013/9/13 Junio C Hamano gits...@pobox.com:

 For systems that need POSIX escape hatch for Apollo Domain ;-), we
 would need a bit more work.  When both path1 and path2 begin with a
 double-dash, we would need to check if they match up to the next
 slash, so that

  - //host1/usr/src and //host1/usr/lib share the same root and the
former can be made to ../src relative to the latter;

  - //host1/usr/src and //host2/usr/lib are of separate roots.

 or something.

 But how could we know which platform supports network pathnames and
 needs such implementation.

 Near the end of

 http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_12

 is this:

 If a pathname begins with two successive slash characters, the
 first component following the leading slash characters may be
 interpreted in an implementation-defined manner, although more than
 two leading slash characters shall be treated as a single slash
 character.

 Two points to note are

  (1) Only paths that begin with exactly two slashes are special.

  (2) As it is implementation-defined, we are not even allowed to
  treat that //host1/usr/src and //host1/usr/lib as sharing the
  same root, and make the former to ../src relative to the
  latter.

 So in the strictest sense, we do not have to bother. As long as we
 make sure we do not molest anything that begins with exactly two
 slashes.


I have checked the behavior of UNC path on Windows (msysGit):

* I can cd to a UNC path:

cd //server1/share1/path

* can cd to other share:

cd ../../share2/path

* and can cd to other server's share:

cd ../../../server2/share/path

That means relative_path(path1, path2) support UNC paths out of the box.
We only need to check both path1 and path2 are UNC paths, or both not.

So, funciton “have_same_root will write like this:


+static int have_same_root(const char *path1, const char *path2)
+{
+   int is_abs1, is_abs2;
+
+   is_abs1 = is_absolute_path(path1);
+   is_abs2 = is_absolute_path(path2);
+   if (is_abs1  is_abs2) {
+   if (is_unc_path(path1) ^ is_unc_path(path2))
+   return 0;
+   return tolower(path1[0]) == tolower(path2[0]);
+   } else {
+   return !is_abs1  !is_abs2;
+   }
+}


-- 
Jiang Xin
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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-17 Thread Johannes Sixt 
Am 17.09.2013 10:24, schrieb Jiang Xin:
 I have checked the behavior of UNC path on Windows (msysGit):
 
 * I can cd to a UNC path:
 
 cd //server1/share1/path
 
 * can cd to other share:
 
 cd ../../share2/path
 
 * and can cd to other server's share:
 
 cd ../../../server2/share/path
 
 That means relative_path(path1, path2) support UNC paths out of the box.
 We only need to check both path1 and path2 are UNC paths, or both not.

Your tests are flawed. You issued the commands in bash, which (or rather
MSYS) does everything for you that you need to make it work. But in
reality it does not, because the system cannot apply .. to //server/share:

$ git ls-remote //srv/public/../repos/his/setups.git
fatal: '//srv/public/../repos/his/setups.git' does not appear to be a
git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

even though the repository (and //srv/public, let me assure) exists:

$ git ls-remote //srv/repos/his/setups.git
bea489b0611a72c41f133343fdccbd3e2b9f80b5HEAD
...

The situation does not change with your latest round (v3).

Please let me suggest not to scratch where there is no itch. ;) Your
round v2 was good enough.

If you really want to check UNC paths, then you must compare two path
components after the the double-slash, not just one.

Furthermore, you should audit all code that references
is_absolute_path(), relative_path(), normalize_path_copy(), and possibly
a few others whether the functions or call sites need improvement.
That's worth a separate patch.

-- Hannes

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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-13 Thread Torsten Bögershausen 
On 13.09.13 06:55, Jiang Xin wrote:
 2013/9/13 Junio C Hamano gits...@pobox.com:
 For systems that need POSIX escape hatch for Apollo Domain ;-), we
 would need a bit more work.  When both path1 and path2 begin with a
 double-dash, we would need to check if they match up to the next
 slash, so that

  - //host1/usr/src and //host1/usr/lib share the same root and the
former can be made to ../src relative to the latter;

  - //host1/usr/src and //host2/usr/lib are of separate roots.

 or something.


 But how could we know which platform supports network pathnames and
 needs such implementation.
Similar to the has_dos_drive_prefix:

For Windows/Mingw we do like this

mingw.h
#define has_dos_drive_prefix(path) (isalpha(*(path))  (path)[1] == ':')

And all other platforms defines has_dos_drive_prefix() to be 0 here
git-compat-util.h
#ifndef has_dos_drive_prefix
#define has_dos_drive_prefix(path) 0
#endif

mingw.h:
#define has_unc_path_prefix(path) ((path)[0] == '/'  (path)[1] == '/')
(Or may be)
#define has_unc_path_prefix(path) (is_dir_sep((path)[0])
is_dir_sep((path)[1]))
 


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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Tvangeste 
Thank you, this fixes the problem with `git svn rebase` on Windows for me.

--Tvangeste

On Thu, Sep 12, 2013 at 11:12 AM, Jiang Xin worldhello@gmail.com wrote:
 Tvangeste found that the relative_path function could not work
 properly on Windows if in and prefix have dos driver prefix.
 ($gmane/234434)

 e.g., When execute: test-path-utils relative_path C:/a/b D:/x/y,
 should return C:/a/b, but returns ../../C:/a/b, which is wrong.

 So make relative_path honor dos_drive_prefix, and add test cases
 for it in t0060.

 Reported-by: Tvangeste i.4m.l...@yandex.ru
 Helped-by: Johannes Sixt j...@kdbg.org
 Signed-off-by: Jiang Xin worldhello@gmail.com
 ---
  path.c| 20 
  t/t0060-path-utils.sh |  4 
  2 files changed, 24 insertions(+)

 diff --git a/path.c b/path.c
 index 7f3324a..ffcdea1 100644
 --- a/path.c
 +++ b/path.c
 @@ -441,6 +441,16 @@ int adjust_shared_perm(const char *path)
 return 0;
  }

 +static int have_same_root(const char *path1, const char *path2)
 +{
 +   int is_abs1, is_abs2;
 +
 +   is_abs1 = is_absolute_path(path1);
 +   is_abs2 = is_absolute_path(path2);
 +   return (is_abs1  is_abs2  !strncasecmp(path1, path2, 1)) ||
 +  (!is_abs1  !is_abs2);
 +}
 +
  /*
   * Give path as relative to prefix.
   *
 @@ -461,6 +471,16 @@ const char *relative_path(const char *in, const char 
 *prefix,
 else if (!prefix_len)
 return in;

 +   if (have_same_root(in, prefix)) {
 +   /* bypass dos_drive, for c: is identical to C: */
 +   if (has_dos_drive_prefix(in)) {
 +   i = 2;
 +   j = 2;
 +   }
 +   } else {
 +   return in;
 +   }
 +
 while (i  prefix_len  j  in_len  prefix[i] == in[j]) {
 if (is_dir_sep(prefix[i])) {
 while (is_dir_sep(prefix[i]))
 diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
 index 76c7792..c3c3b33 100755
 --- a/t/t0060-path-utils.sh
 +++ b/t/t0060-path-utils.sh
 @@ -208,6 +208,10 @@ relative_path a/b/ a/b ./
  relative_path aa/b ../
  relative_path x/y  a/b ../../x/y
  relative_path a/c  a/b ../c
 +relative_path a/b  /x/ya/b
 +relative_path /a/b x/y /a/bPOSIX
 +relative_path d:/a/b   D:/a/c  ../bMINGW
 +relative_path C:/a/b   D:/a/c  C:/a/b  MINGW
  relative_path a/b  empty   a/b
  relative_path a/b  nulla/b
  relative_path empty/a/b./
 --
 1.8.3.rc2.14.g5ac1b82

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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Torsten Bögershausen 
On 2013-09-12 11.12, Jiang Xin wrote:
 Tvangeste found that the relative_path function could not work
 properly on Windows if in and prefix have dos driver prefix.
 ($gmane/234434)
 
 e.g., When execute: test-path-utils relative_path C:/a/b D:/x/y,
 should return C:/a/b, but returns ../../C:/a/b, which is wrong.
 
 So make relative_path honor dos_drive_prefix, and add test cases
 for it in t0060.
 
 Reported-by: Tvangeste i.4m.l...@yandex.ru
 Helped-by: Johannes Sixt j...@kdbg.org
 Signed-off-by: Jiang Xin worldhello@gmail.com
 ---
  path.c| 20 
  t/t0060-path-utils.sh |  4 
  2 files changed, 24 insertions(+)
 
 diff --git a/path.c b/path.c
 index 7f3324a..ffcdea1 100644
 --- a/path.c
 +++ b/path.c
 @@ -441,6 +441,16 @@ int adjust_shared_perm(const char *path)
   return 0;
  }
  
 +static int have_same_root(const char *path1, const char *path2)
 +{
 + int is_abs1, is_abs2;
 +
 + is_abs1 = is_absolute_path(path1);
 + is_abs2 = is_absolute_path(path2);
 + return (is_abs1  is_abs2  !strncasecmp(path1, path2, 1)) ||
   ^^^
I wonder: should strncasecmp() be replaced with strncmp_icase() ?

See dir.c: 
int strncmp_icase(const char *a, const char *b, size_t count)
{
return ignore_case ? strncasecmp(a, b, count) : strncmp(a, b, count);
}
/Torsten











 +(!is_abs1  !is_abs2);
 +}
 +
  /*
   * Give path as relative to prefix.
   *
 @@ -461,6 +471,16 @@ const char *relative_path(const char *in, const char 
 *prefix,
   else if (!prefix_len)
   return in;
  
 + if (have_same_root(in, prefix)) {
 + /* bypass dos_drive, for c: is identical to C: */
 + if (has_dos_drive_prefix(in)) {
 + i = 2;
 + j = 2;
 + }
 + } else {
 + return in;
 + }
 +
   while (i  prefix_len  j  in_len  prefix[i] == in[j]) {
   if (is_dir_sep(prefix[i])) {
   while (is_dir_sep(prefix[i]))
 diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
 index 76c7792..c3c3b33 100755
 --- a/t/t0060-path-utils.sh
 +++ b/t/t0060-path-utils.sh
 @@ -208,6 +208,10 @@ relative_path a/b/   a/b ./
  relative_path a  a/b ../
  relative_path x/ya/b ../../x/y
  relative_path a/ca/b ../c
 +relative_path a/b/x/ya/b
 +relative_path /a/b   x/y /a/bPOSIX
 +relative_path d:/a/b D:/a/c  ../bMINGW
 +relative_path C:/a/b D:/a/c  C:/a/b  MINGW
  relative_path a/bempty   a/b
  relative_path a/bnulla/b
  relative_path empty  /a/b./
 

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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Karsten Blees 
Am 12.09.2013 11:12, schrieb Jiang Xin:
 Tvangeste found that the relative_path function could not work
 properly on Windows if in and prefix have dos driver prefix.
 ($gmane/234434)
 
 e.g., When execute: test-path-utils relative_path C:/a/b D:/x/y,
 should return C:/a/b, but returns ../../C:/a/b, which is wrong.
 
 So make relative_path honor dos_drive_prefix, and add test cases
 for it in t0060.
 

I still don't think that cd'ing through the root is a Good Thing for absolute 
paths, as it is not possible to do so in general.

POSIX says the meaning of '//' is implementation-defined [1].

Cygwin supports //hostname/share/directory/file. You cannot cd to the hostname 
(i.e. root would be //hostname/share).

On Windows, we have drive letters, UNC paths and namespaces:
C:\directory\file
\\hostname\share\directory\file (same as cygwin)
\\?\C:\directory\file
\\?\UNC\hostname\share\directory\file

I'm not sure about '//' support on other git platforms (the most likely 
candidate would probably be HP-UX, as HP bought Apollo/DomainOS, which 
supported '//hostname/directory/file back in 1981).


You could of course handle all these special cases. However, with the POSIX 
definition above, the only reliable and future-proof way to check if we can cd 
out of a path component of an _absolute_ path is to actually try it until we 
get an error. And we probably don't want to do actual IO in relative_path 
(which is pure string manipulation so far).

[1] 
http://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xbd_chap04.html#tag_21_04_12


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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Junio C Hamano 
Torsten Bögershausen tbo...@web.de writes:

 +static int have_same_root(const char *path1, const char *path2)
 +{
 +int is_abs1, is_abs2;
 +
 +is_abs1 = is_absolute_path(path1);
 +is_abs2 = is_absolute_path(path2);
 +return (is_abs1  is_abs2  !strncasecmp(path1, path2, 1)) ||
^^^
 I wonder: should strncasecmp() be replaced with strncmp_icase() ?

True.

 See dir.c: 
 int strncmp_icase(const char *a, const char *b, size_t count)
 {
   return ignore_case ? strncasecmp(a, b, count) : strncmp(a, b, count);
 }
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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Johannes Sixt 
Am 12.09.2013 16:13, schrieb Torsten Bögershausen:
 On 2013-09-12 11.12, Jiang Xin wrote:
 +static int have_same_root(const char *path1, const char *path2)
 +{
 +int is_abs1, is_abs2;
 +
 +is_abs1 = is_absolute_path(path1);
 +is_abs2 = is_absolute_path(path2);
 +return (is_abs1  is_abs2  !strncasecmp(path1, path2, 1)) ||
^^^
 I wonder: should strncasecmp() be replaced with strncmp_icase() ?

I don't think so: On POSIX, it is irrelevant, because the call will only
compare a slash to a slash. On Windows, it compares the drive letters
(or a slash); it is *always* case-insensitive, even if the volume
mounted is NTFS with case-sensitivity enabled and core.ignorecase is false.

 See dir.c: 
 int strncmp_icase(const char *a, const char *b, size_t count)
 {
   return ignore_case ? strncasecmp(a, b, count) : strncmp(a, b, count);
 }

-- Hannes

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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Junio C Hamano 
Johannes Sixt j...@kdbg.org writes:

 Am 12.09.2013 16:13, schrieb Torsten Bögershausen:
 On 2013-09-12 11.12, Jiang Xin wrote:
 +static int have_same_root(const char *path1, const char *path2)
 +{
 +   int is_abs1, is_abs2;
 +
 +   is_abs1 = is_absolute_path(path1);
 +   is_abs2 = is_absolute_path(path2);
 +   return (is_abs1  is_abs2  !strncasecmp(path1, path2, 1)) ||
^^^
 I wonder: should strncasecmp() be replaced with strncmp_icase() ?

 I don't think so: On POSIX, it is irrelevant, because the call will only
 compare a slash to a slash. On Windows, it compares the drive letters
 (or a slash); it is *always* case-insensitive, even if the volume
 mounted is NTFS with case-sensitivity enabled and core.ignorecase is false.

Ah, you are right, of course.  We could even do

tolower(path1[0]) == tolower(path2[0])

which might be more explicit.

For systems that need POSIX escape hatch for Apollo Domain ;-), we
would need a bit more work.  When both path1 and path2 begin with a
double-dash, we would need to check if they match up to the next
slash, so that

 - //host1/usr/src and //host1/usr/lib share the same root and the
   former can be made to ../src relative to the latter;

 - //host1/usr/src and //host2/usr/lib are of separate roots.

or something.


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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Jiang Xin 
2013/9/13 Junio C Hamano gits...@pobox.com:

 For systems that need POSIX escape hatch for Apollo Domain ;-), we
 would need a bit more work.  When both path1 and path2 begin with a
 double-dash, we would need to check if they match up to the next
 slash, so that

  - //host1/usr/src and //host1/usr/lib share the same root and the
former can be made to ../src relative to the latter;

  - //host1/usr/src and //host2/usr/lib are of separate roots.

 or something.



But how could we know which platform supports network pathnames and
needs such implementation.

-- 
Jiang Xin
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Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

2013-09-12 Thread Junio C Hamano 
Jiang Xin worldhello@gmail.com writes:

 2013/9/13 Junio C Hamano gits...@pobox.com:

 For systems that need POSIX escape hatch for Apollo Domain ;-), we
 would need a bit more work.  When both path1 and path2 begin with a
 double-dash, we would need to check if they match up to the next
 slash, so that

  - //host1/usr/src and //host1/usr/lib share the same root and the
former can be made to ../src relative to the latter;

  - //host1/usr/src and //host2/usr/lib are of separate roots.

 or something.

 But how could we know which platform supports network pathnames and
 needs such implementation.

Near the end of

http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_12

is this:

If a pathname begins with two successive slash characters, the
first component following the leading slash characters may be
interpreted in an implementation-defined manner, although more than
two leading slash characters shall be treated as a single slash
character.

Two points to note are

 (1) Only paths that begin with exactly two slashes are special.

 (2) As it is implementation-defined, we are not even allowed to
 treat that //host1/usr/src and //host1/usr/lib as sharing the
 same root, and make the former to ../src relative to the
 latter.

So in the strictest sense, we do not have to bother. As long as we
make sure we do not molest anything that begins with exactly two
slashes.

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