Add is_absolute_path() and make_absolute_path()

This patch adds convenience functions to work with absolute paths.
The function is_absolute_path() should help the efforts to integrate
the MinGW fork.

Note that make_absolute_path() returns a pointer to a static buffer.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index ff5fc5fbe2e8239bf2e0ccbae6072b59842df7c5..b593446efb1d86971de66f0928e63a879ae3aa59 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -944,7 +944,7 @@ endif
 
 ### Testing rules
 
-TEST_PROGRAMS = test-chmtime$X test-genrandom$X test-date$X test-delta$X test-sha1$X test-match-trees$X
+TEST_PROGRAMS = test-chmtime$X test-genrandom$X test-date$X test-delta$X test-sha1$X test-match-trees$X test-absolute-path$X
 
 all:: $(TEST_PROGRAMS)
 

diff --git a/cache.h b/cache.h
index 53801b8089e0fbea5e36414432ef9aa7d1313781..98af53040d1e0274895237fdf6a3699b91bdb20f 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -358,6 +358,11 @@ int git_config_perm(const char *var, const char *value);
 int adjust_shared_perm(const char *path);
 int safe_create_leading_directories(char *path);
 char *enter_repo(char *path, int strict);
+static inline int is_absolute_path(const char *path)
+{
+       return path[0] == '/';
+}
+const char *make_absolute_path(const char *path);
 
 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 extern int sha1_object_info(const unsigned char *, unsigned long *);

diff --git a/path.c b/path.c
index dfff41f62668709e80cc54f816394303e8f6cefc..42609524a55ad017557d48bedf26906cc4405d0a 100644 (file)
--- a/path.c
+++ b/path.c
@@ -288,3 +288,68 @@ int adjust_shared_perm(const char *path)
                return -2;
        return 0;
 }
+
+/* We allow "recursive" symbolic links. Only within reason, though. */
+#define MAXDEPTH 5
+
+const char *make_absolute_path(const char *path)
+{
+       static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
+       char cwd[1024] = "";
+       int buf_index = 1, len;
+
+       int depth = MAXDEPTH;
+       char *last_elem = NULL;
+       struct stat st;
+
+       if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
+               die ("Too long path: %.*s", 60, path);
+
+       while (depth--) {
+               if (stat(buf, &st) || !S_ISDIR(st.st_mode)) {
+                       char *last_slash = strrchr(buf, '/');
+                       if (last_slash) {
+                               *last_slash = '\0';
+                               last_elem = xstrdup(last_slash + 1);
+                       } else
+                               last_elem = xstrdup(buf);
+               }
+
+               if (*buf) {
+                       if (!*cwd && !getcwd(cwd, sizeof(cwd)))
+                               die ("Could not get current working directory");
+
+                       if (chdir(buf))
+                               die ("Could not switch to '%s'", buf);
+               }
+               if (!getcwd(buf, PATH_MAX))
+                       die ("Could not get current working directory");
+
+               if (last_elem) {
+                       int len = strlen(buf);
+                       if (len + strlen(last_elem) + 2 > PATH_MAX)
+                               die ("Too long path name: '%s/%s'",
+                                               buf, last_elem);
+                       buf[len] = '/';
+                       strcpy(buf + len + 1, last_elem);
+                       free(last_elem);
+                       last_elem = NULL;
+               }
+
+               if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
+                       len = readlink(buf, next_buf, PATH_MAX);
+                       if (len < 0)
+                               die ("Invalid symlink: %s", buf);
+                       next_buf[len] = '\0';
+                       buf = next_buf;
+                       buf_index = 1 - buf_index;
+                       next_buf = bufs[buf_index];
+               } else
+                       break;
+       }
+
+       if (*cwd && chdir(cwd))
+               die ("Could not change back to '%s'", cwd);
+
+       return buf;
+}

diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 4bba9c0717731bfc6912ac28f98c10aa0f3e17fd..4e49d590651363631a1f3a795d3c1679a70fb05f 100755 (executable)
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -281,4 +281,20 @@ test_expect_success 'update-index D/F conflict' '
        test $numpath0 = 1
 '
 
+test_expect_success 'absolute path works as expected' '
+       mkdir first &&
+       ln -s ../.git first/.git &&
+       mkdir second &&
+       ln -s ../first second/other &&
+       mkdir third &&
+       dir="$(cd .git; pwd -P)" &&
+       dir2=third/../second/other/.git &&
+       test "$dir" = "$(test-absolute-path $dir2)" &&
+       file="$dir"/index &&
+       test "$file" = "$(test-absolute-path $dir2/index)" &&
+       ln -s ../first/file .git/syml &&
+       sym="$(cd first; pwd -P)"/file &&
+       test "$sym" = "$(test-absolute-path $dir2/syml)"
+'
+
 test_done

diff --git a/test-absolute-path.c b/test-absolute-path.c
new file mode 100644 (file)
index 0000000..c959ea2
--- /dev/null
+++ b/test-absolute-path.c
@@ -0,0 +1,11 @@
+#include "cache.h"
+
+int main(int argc, char **argv)
+{
+       while (argc > 1) {
+               puts(make_absolute_path(argv[1]));
+               argc--;
+               argv++;
+       }
+       return 0;
+}