Documentation: more examples.

diff --git a/refs.c b/refs.c
index 6aa6aec82dbd5510d43dea07362399f57669eeef..d2aec73edcbe06cf63009ac7dd85fa53b6c995b9 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -2,11 +2,14 @@
 #include "cache.h"
 
 #include <errno.h>
-#include <ctype.h>
 
 /* We allow "recursive" symbolic refs. Only within reason, though */
 #define MAXDEPTH 5
 
+#ifndef USE_SYMLINK_HEAD
+#define USE_SYMLINK_HEAD 1
+#endif
+
 const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
 {
        int depth = MAXDEPTH, len;
@@ -71,6 +74,43 @@ const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
        return path;
 }
 
+int create_symref(const char *git_HEAD, const char *refs_heads_master)
+{
+       const char *lockpath;
+       char ref[1000];
+       int fd, len, written;
+
+#if USE_SYMLINK_HEAD
+       if (!only_use_symrefs) {
+               unlink(git_HEAD);
+               if (!symlink(refs_heads_master, git_HEAD))
+                       return 0;
+               fprintf(stderr, "no symlink - falling back to symbolic ref\n");
+       }
+#endif
+
+       len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
+       if (sizeof(ref) <= len) {
+               error("refname too long: %s", refs_heads_master);
+               return -1;
+       }
+       lockpath = mkpath("%s.lock", git_HEAD);
+       fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666); 
+       written = write(fd, ref, len);
+       close(fd);
+       if (written != len) {
+               unlink(lockpath);
+               error("Unable to write to %s", lockpath);
+               return -2;
+       }
+       if (rename(lockpath, git_HEAD) < 0) {
+               unlink(lockpath);
+               error("Unable to create %s", git_HEAD);
+               return -3;
+       }
+       return 0;
+}
+
 int read_ref(const char *filename, unsigned char *sha1)
 {
        if (resolve_ref(filename, sha1, 1))
@@ -252,23 +292,62 @@ int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
                return -1;
        filename = ref_file_name(ref);
        lock_filename = ref_lock_file_name(ref);
+       if (safe_create_leading_directories(filename))
+               die("unable to create leading directory for %s", filename);
        retval = write_ref_file(filename, lock_filename, fd, sha1);
        free(filename);
        free(lock_filename);
        return retval;
 }
 
+/*
+ * Make sure "ref" is something reasonable to have under ".git/refs/";
+ * We do not like it if:
+ *
+ * - any path component of it begins with ".", or
+ * - it has double dots "..", or
+ * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
+ * - it ends with a "/".
+ */
+
+static inline int bad_ref_char(int ch)
+{
+       return (((unsigned) ch) <= ' ' ||
+               ch == '~' || ch == '^' || ch == ':');
+}
+
 int check_ref_format(const char *ref)
 {
-       char *middle;
-       if (ref[0] == '.' || ref[0] == '/')
-               return -1;
-       middle = strchr(ref, '/');
-       if (!middle || !middle[1])
-               return -1;
-       if (strchr(middle + 1, '/'))
-               return -1;
-       return 0;
+       int ch, level;
+       const char *cp = ref;
+
+       level = 0;
+       while (1) {
+               while ((ch = *cp++) == '/')
+                       ; /* tolerate duplicated slashes */
+               if (!ch)
+                       return -1; /* should not end with slashes */
+
+               /* we are at the beginning of the path component */
+               if (ch == '.' || bad_ref_char(ch))
+                       return -1;
+
+               /* scan the rest of the path component */
+               while ((ch = *cp++) != 0) {
+                       if (bad_ref_char(ch))
+                               return -1;
+                       if (ch == '/')
+                               break;
+                       if (ch == '.' && *cp == '.')
+                               return -1;
+               }
+               level++;
+               if (!ch) {
+                       if (level < 2)
+                               return -1; /* at least of form "heads/blah" */
+                       return 0;
+               }
+       }
 }
 
 int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
@@ -281,6 +360,8 @@ int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
                return -1;
        filename = ref_file_name(ref);
        lock_filename = ref_lock_file_name(ref);
+       if (safe_create_leading_directories(filename))
+               die("unable to create leading directory for %s", filename);
        fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
        if (fd < 0) {
                error("Writing %s", lock_filename);