diff options
| -rw-r--r-- | Makefile | 3 | ||||
| -rw-r--r-- | cache.h | 1 | ||||
| -rw-r--r-- | refs.c | 173 | ||||
| -rw-r--r-- | refs.h | 21 | ||||
| -rw-r--r-- | sha1_file.c | 11 |
5 files changed, 207 insertions, 2 deletions
@@ -40,7 +40,8 @@ install: $(PROG) $(SCRIPTS) $(INSTALL) $(PROG) $(SCRIPTS) $(dest)$(bin) LIB_OBJS=read-cache.o sha1_file.o usage.o object.o commit.o tree.o blob.o \ - tag.o delta.o date.o index.o diff-delta.o patch-delta.o entry.o epoch.o + tag.o delta.o date.o index.o diff-delta.o patch-delta.o entry.o \ + epoch.o refs.o LIB_FILE=libgit.a LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h epoch.h @@ -117,6 +117,7 @@ extern unsigned int active_nr, active_alloc, active_cache_changed; #define INDEX_ENVIRONMENT "GIT_INDEX_FILE" extern char *get_object_directory(void); +extern char *get_refs_directory(void); extern char *get_index_file(void); #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES" diff --git a/refs.c b/refs.c new file mode 100644 index 0000000000..9973d1fc21 --- /dev/null +++ b/refs.c @@ -0,0 +1,173 @@ +#include "refs.h" +#include "cache.h" + +#include <errno.h> + +static char *ref_file_name(const char *ref) +{ + char *base = get_refs_directory(); + int baselen = strlen(base); + int reflen = strlen(ref); + char *ret = xmalloc(baselen + 2 + reflen); + sprintf(ret, "%s/%s", base, ref); + return ret; +} + +static char *ref_lock_file_name(const char *ref) +{ + char *base = get_refs_directory(); + int baselen = strlen(base); + int reflen = strlen(ref); + char *ret = xmalloc(baselen + 7 + reflen); + sprintf(ret, "%s/%s.lock", base, ref); + return ret; +} + +static int read_ref_file(const char *filename, unsigned char *sha1) { + int fd = open(filename, O_RDONLY); + char hex[41]; + if (fd < 0) { + return error("Couldn't open %s\n", filename); + } + if ((read(fd, hex, 41) < 41) || + (hex[40] != '\n') || + get_sha1_hex(hex, sha1)) { + error("Couldn't read a hash from %s\n", filename); + close(fd); + return -1; + } + close(fd); + return 0; +} + +int get_ref_sha1(const char *ref, unsigned char *sha1) +{ + char *filename; + int retval; + if (check_ref_format(ref)) + return -1; + filename = ref_file_name(ref); + retval = read_ref_file(filename, sha1); + free(filename); + return retval; +} + +static int lock_ref_file(const char *filename, const char *lock_filename, + const unsigned char *old_sha1) +{ + int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666); + unsigned char current_sha1[20]; + int retval; + if (fd < 0) { + return error("Couldn't open lock file for %s: %s", + filename, strerror(errno)); + } + retval = read_ref_file(filename, current_sha1); + if (old_sha1) { + if (retval) { + close(fd); + unlink(lock_filename); + return error("Could not read the current value of %s", + filename); + } + if (memcmp(current_sha1, old_sha1, 20)) { + close(fd); + unlink(lock_filename); + error("The current value of %s is %s", + filename, sha1_to_hex(current_sha1)); + return error("Expected %s", + sha1_to_hex(old_sha1)); + } + } else { + if (!retval) { + close(fd); + unlink(lock_filename); + return error("Unexpectedly found a value of %s for %s", + sha1_to_hex(current_sha1), filename); + } + } + return fd; +} + +int lock_ref_sha1(const char *ref, const unsigned char *old_sha1) +{ + char *filename; + char *lock_filename; + int retval; + if (check_ref_format(ref)) + return -1; + filename = ref_file_name(ref); + lock_filename = ref_lock_file_name(ref); + retval = lock_ref_file(filename, lock_filename, old_sha1); + free(filename); + free(lock_filename); + return retval; +} + +static int write_ref_file(const char *filename, + const char *lock_filename, int fd, + const unsigned char *sha1) +{ + char *hex = sha1_to_hex(sha1); + char term = '\n'; + if (write(fd, hex, 40) < 40 || + write(fd, &term, 1) < 1) { + error("Couldn't write %s\n", filename); + close(fd); + return -1; + } + close(fd); + rename(lock_filename, filename); + return 0; +} + +int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1) +{ + char *filename; + char *lock_filename; + int retval; + if (fd < 0) + return -1; + if (check_ref_format(ref)) + return -1; + filename = ref_file_name(ref); + lock_filename = ref_lock_file_name(ref); + retval = write_ref_file(filename, lock_filename, fd, sha1); + free(filename); + free(lock_filename); + return retval; +} + +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 write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1) +{ + char *filename; + char *lock_filename; + int fd; + int retval; + if (check_ref_format(ref)) + return -1; + filename = ref_file_name(ref); + lock_filename = ref_lock_file_name(ref); + fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666); + if (fd < 0) { + error("Writing %s", lock_filename); + perror("Open"); + } + retval = write_ref_file(filename, lock_filename, fd, sha1); + free(filename); + free(lock_filename); + return retval; +} diff --git a/refs.h b/refs.h new file mode 100644 index 0000000000..60cf48086f --- /dev/null +++ b/refs.h @@ -0,0 +1,21 @@ +#ifndef REFS_H +#define REFS_H + +/** Reads the refs file specified into sha1 **/ +extern int get_ref_sha1(const char *ref, unsigned char *sha1); + +/** Locks ref and returns the fd to give to write_ref_sha1() if the ref + * has the given value currently; otherwise, returns -1. + **/ +extern int lock_ref_sha1(const char *ref, const unsigned char *old_sha1); + +/** Writes sha1 into the refs file specified, locked with the given fd. **/ +extern int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1); + +/** Writes sha1 into the refs file specified. **/ +extern int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1); + +/** Returns 0 if target has the right format for a ref. **/ +extern int check_ref_format(const char *target); + +#endif /* REFS_H */ diff --git a/sha1_file.c b/sha1_file.c index a2ba4c81db..7cfd43c51b 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -58,7 +58,7 @@ static int get_sha1_file(const char *path, unsigned char *result) return get_sha1_hex(buffer, result); } -static char *git_dir, *git_object_dir, *git_index_file; +static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir; static void setup_git_env(void) { git_dir = gitenv(GIT_DIR_ENVIRONMENT); @@ -69,6 +69,8 @@ static void setup_git_env(void) git_object_dir = xmalloc(strlen(git_dir) + 9); sprintf(git_object_dir, "%s/objects", git_dir); } + git_refs_dir = xmalloc(strlen(git_dir) + 6); + sprintf(git_refs_dir, "%s/refs", git_dir); git_index_file = gitenv(INDEX_ENVIRONMENT); if (!git_index_file) { git_index_file = xmalloc(strlen(git_dir) + 7); @@ -83,6 +85,13 @@ char *get_object_directory(void) return git_object_dir; } +char *get_refs_directory(void) +{ + if (!git_refs_dir) + setup_git_env(); + return git_refs_dir; +} + char *get_index_file(void) { if (!git_index_file) |