Update get_sha1() to grok extended format.

Everybody envies rev-parse, who is the only one that can grok
the extended sha1 format.  Move the get_extended_sha1() out of
rev-parse, rename it to get_sha1() and make it available to
everybody else.

The one I posted earlier to the list had one bug where it did
not handle a name that ends with a digit correctly (it
incorrectly tried the "Nth parent" path).  This commit fixes it.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Makefile b/Makefile
index 7b5397e..425e9a4 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -95,7 +95,8 @@ LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h epoch.h csum-file.h
        pack.h pkt-line.h refs.h
 LIB_OBJS=read-cache.o sha1_file.o usage.o object.o commit.o tree.o blob.o \
         tag.o date.o index.o diff-delta.o patch-delta.o entry.o path.o \
-        refs.o csum-file.o pack-check.o pkt-line.o connect.o ident.o
+        refs.o csum-file.o pack-check.o pkt-line.o connect.o ident.o \
+        sha1_name.o
 
 LIB_H += rev-cache.h
 LIB_OBJS += rev-cache.o

diff --git a/rev-parse.c b/rev-parse.c
index 4bd58eb..1965e90 100644 (file)
--- a/rev-parse.c
+++ b/rev-parse.c
@@ -21,8 +21,6 @@ static int output_sq = 0;
 #define REVERSED 1
 static int show_type = NORMAL;
 
-static int get_extended_sha1(char *name, unsigned char *sha1);
-
 /*
  * Some arguments are relevant "revision" arguments,
  * others are about output format or other details.
@@ -107,182 +105,6 @@ static void show_arg(char *arg)
                show_norev(arg);
 }
 
-static int get_parent(char *name, unsigned char *result, int idx)
-{
-       unsigned char sha1[20];
-       int ret = get_extended_sha1(name, sha1);
-       struct commit *commit;
-       struct commit_list *p;
-
-       if (ret)
-               return ret;
-       commit = lookup_commit_reference(sha1);
-       if (!commit)
-               return -1;
-       if (parse_commit(commit))
-               return -1;
-       if (!idx) {
-               memcpy(result, commit->object.sha1, 20);
-               return 0;
-       }
-       p = commit->parents;
-       while (p) {
-               if (!--idx) {
-                       memcpy(result, p->item->object.sha1, 20);
-                       return 0;
-               }
-               p = p->next;
-       }
-       return -1;
-}
-
-static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
-{
-       static char dirname[PATH_MAX];
-       char hex[40];
-       DIR *dir;
-       int found;
-
-       snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
-       dir = opendir(dirname);
-       sprintf(hex, "%.2s", name);
-       found = 0;
-       if (dir) {
-               struct dirent *de;
-               while ((de = readdir(dir)) != NULL) {
-                       if (strlen(de->d_name) != 38)
-                               continue;
-                       if (memcmp(de->d_name, name + 2, len-2))
-                               continue;
-                       memcpy(hex + 2, de->d_name, 38);
-                       if (++found > 1)
-                               break;
-               }
-               closedir(dir);
-       }
-       if (found == 1)
-               return get_sha1_hex(hex, sha1) == 0;
-       return 0;
-}
-
-static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
-{
-       do {
-               if (*a != *b)
-                       return 0;
-               a++;
-               b++;
-               len -= 2;
-       } while (len > 1);
-       if (len)
-               if ((*a ^ *b) & 0xf0)
-                       return 0;
-       return 1;
-}
-
-static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
-{
-       struct packed_git *p;
-
-       prepare_packed_git();
-       for (p = packed_git; p; p = p->next) {
-               unsigned num = num_packed_objects(p);
-               unsigned first = 0, last = num;
-               while (first < last) {
-                       unsigned mid = (first + last) / 2;
-                       unsigned char now[20];
-                       int cmp;
-
-                       nth_packed_object_sha1(p, mid, now);
-                       cmp = memcmp(match, now, 20);
-                       if (!cmp) {
-                               first = mid;
-                               break;
-                       }
-                       if (cmp > 0) {
-                               first = mid+1;
-                               continue;
-                       }
-                       last = mid;
-               }
-               if (first < num) {
-                       unsigned char now[20], next[20];
-                       nth_packed_object_sha1(p, first, now);
-                       if (match_sha(len, match, now)) {
-                               if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
-                                       memcpy(sha1, now, 20);
-                                       return 1;
-                               }
-                       }
-               }       
-       }
-       return 0;
-}
-
-static int get_short_sha1(char *name, unsigned char *sha1)
-{
-       int i;
-       char canonical[40];
-       unsigned char res[20];
-
-       memset(res, 0, 20);
-       memset(canonical, 'x', 40);
-       for (i = 0;;i++) {
-               unsigned char c = name[i];
-               unsigned char val;
-               if (!c || i > 40)
-                       break;
-               if (c >= '0' && c <= '9')
-                       val = c - '0';
-               else if (c >= 'a' && c <= 'f')
-                       val = c - 'a' + 10;
-               else if (c >= 'A' && c <='F') {
-                       val = c - 'A' + 10;
-                       c -= 'A' - 'a';
-               }
-               else
-                       return -1;
-               canonical[i] = c;
-               if (!(i & 1))
-                       val <<= 4;
-               res[i >> 1] |= val;
-       }
-       if (i < 4)
-               return -1;
-       if (find_short_object_filename(i, canonical, sha1))
-               return 0;
-       if (find_short_packed_object(i, res, sha1))
-               return 0;
-       return -1;
-}
-
-/*
- * This is like "get_sha1()", except it allows "sha1 expressions",
- * notably "xyz^" for "parent of xyz"
- */
-static int get_extended_sha1(char *name, unsigned char *sha1)
-{
-       int parent, ret;
-       int len = strlen(name);
-
-       parent = 1;
-       if (len > 2 && name[len-1] >= '0' && name[len-1] <= '9') {
-               parent = name[len-1] - '0';
-               len--;
-       }
-       if (len > 1 && name[len-1] == '^') {
-               name[len-1] = 0;
-               ret = get_parent(name, sha1, parent);
-               name[len-1] = '^';
-               if (!ret)
-                       return 0;
-       }
-       ret = get_sha1(name, sha1);
-       if (!ret)
-               return 0;
-       return get_short_sha1(name, sha1);
-}
-
 static void show_default(void)
 {
        char *s = def;
@@ -291,7 +113,7 @@ static void show_default(void)
                unsigned char sha1[20];
 
                def = NULL;
-               if (!get_extended_sha1(s, sha1)) {
+               if (!get_sha1(s, sha1)) {
                        show_rev(NORMAL, sha1);
                        return;
                }
@@ -372,10 +194,10 @@ int main(int argc, char **argv)
                        unsigned char end[20];
                        char *n = dotdot+2;
                        *dotdot = 0;
-                       if (!get_extended_sha1(arg, sha1)) {
+                       if (!get_sha1(arg, sha1)) {
                                if (!*n)
                                        n = "HEAD";
-                               if (!get_extended_sha1(n, end)) {
+                               if (!get_sha1(n, end)) {
                                        if (no_revs)
                                                continue;
                                        def = NULL;
@@ -386,14 +208,14 @@ int main(int argc, char **argv)
                        }
                        *dotdot = '.';
                }
-               if (!get_extended_sha1(arg, sha1)) {
+               if (!get_sha1(arg, sha1)) {
                        if (no_revs)
                                continue;
                        def = NULL;
                        show_rev(NORMAL, sha1);
                        continue;
                }
-               if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
+               if (*arg == '^' && !get_sha1(arg+1, sha1)) {
                        if (no_revs)
                                continue;
                        def = NULL;

diff --git a/sha1_file.c b/sha1_file.c
index df5eb2a..a17a6d1 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -46,21 +46,6 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
        return 0;
 }
 
-static int get_sha1_file(const char *path, unsigned char *result)
-{
-       char buffer[60];
-       int fd = open(path, O_RDONLY);
-       int len;
-
-       if (fd < 0)
-               return -1;
-       len = read(fd, buffer, sizeof(buffer));
-       close(fd);
-       if (len < 40)
-               return -1;
-       return get_sha1_hex(buffer, result);
-}
-
 static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir,
        *git_graft_file;
 static void setup_git_env(void)
@@ -132,30 +117,6 @@ int safe_create_leading_directories(char *path)
        return 0;
 }
 
-int get_sha1(const char *str, unsigned char *sha1)
-{
-       static const char *prefix[] = {
-               "",
-               "refs",
-               "refs/tags",
-               "refs/heads",
-               "refs/snap",
-               NULL
-       };
-       const char **p;
-
-       if (!get_sha1_hex(str, sha1))
-               return 0;
-
-       for (p = prefix; *p; p++) {
-               char * pathname = git_path("%s/%s", *p, str);
-               if (!get_sha1_file(pathname, sha1))
-                       return 0;
-       }
-
-       return -1;
-}
-
 char * sha1_to_hex(const unsigned char *sha1)
 {
        static char buffer[50];

diff --git a/sha1_name.c b/sha1_name.c
new file mode 100644 (file)
index 0000000..df3ba2d
--- /dev/null
+++ b/sha1_name.c
@@ -0,0 +1,228 @@
+#include "cache.h"
+#include "commit.h"
+
+static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
+{
+       static char dirname[PATH_MAX];
+       char hex[40];
+       DIR *dir;
+       int found;
+
+       snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
+       dir = opendir(dirname);
+       sprintf(hex, "%.2s", name);
+       found = 0;
+       if (dir) {
+               struct dirent *de;
+               while ((de = readdir(dir)) != NULL) {
+                       if (strlen(de->d_name) != 38)
+                               continue;
+                       if (memcmp(de->d_name, name + 2, len-2))
+                               continue;
+                       memcpy(hex + 2, de->d_name, 38);
+                       if (++found > 1)
+                               break;
+               }
+               closedir(dir);
+       }
+       if (found == 1)
+               return get_sha1_hex(hex, sha1) == 0;
+       return 0;
+}
+
+static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
+{
+       do {
+               if (*a != *b)
+                       return 0;
+               a++;
+               b++;
+               len -= 2;
+       } while (len > 1);
+       if (len)
+               if ((*a ^ *b) & 0xf0)
+                       return 0;
+       return 1;
+}
+
+static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
+{
+       struct packed_git *p;
+
+       prepare_packed_git();
+       for (p = packed_git; p; p = p->next) {
+               unsigned num = num_packed_objects(p);
+               unsigned first = 0, last = num;
+               while (first < last) {
+                       unsigned mid = (first + last) / 2;
+                       unsigned char now[20];
+                       int cmp;
+
+                       nth_packed_object_sha1(p, mid, now);
+                       cmp = memcmp(match, now, 20);
+                       if (!cmp) {
+                               first = mid;
+                               break;
+                       }
+                       if (cmp > 0) {
+                               first = mid+1;
+                               continue;
+                       }
+                       last = mid;
+               }
+               if (first < num) {
+                       unsigned char now[20], next[20];
+                       nth_packed_object_sha1(p, first, now);
+                       if (match_sha(len, match, now)) {
+                               if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
+                                       memcpy(sha1, now, 20);
+                                       return 1;
+                               }
+                       }
+               }
+       }
+       return 0;
+}
+
+static int get_short_sha1(const char *name, unsigned char *sha1)
+{
+       int i;
+       char canonical[40];
+       unsigned char res[20];
+
+       memset(res, 0, 20);
+       memset(canonical, 'x', 40);
+       for (i = 0;;i++) {
+               unsigned char c = name[i];
+               unsigned char val;
+               if (!c || i > 40)
+                       break;
+               if (c >= '0' && c <= '9')
+                       val = c - '0';
+               else if (c >= 'a' && c <= 'f')
+                       val = c - 'a' + 10;
+               else if (c >= 'A' && c <='F') {
+                       val = c - 'A' + 10;
+                       c -= 'A' - 'a';
+               }
+               else
+                       return -1;
+               canonical[i] = c;
+               if (!(i & 1))
+                       val <<= 4;
+               res[i >> 1] |= val;
+       }
+       if (i < 4)
+               return -1;
+       if (find_short_object_filename(i, canonical, sha1))
+               return 0;
+       if (find_short_packed_object(i, res, sha1))
+               return 0;
+       return -1;
+}
+
+static int get_sha1_file(const char *path, unsigned char *result)
+{
+       char buffer[60];
+       int fd = open(path, O_RDONLY);
+       int len;
+
+       if (fd < 0)
+               return -1;
+       len = read(fd, buffer, sizeof(buffer));
+       close(fd);
+       if (len < 40)
+               return -1;
+       return get_sha1_hex(buffer, result);
+}
+
+static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
+{
+       static const char *prefix[] = {
+               "",
+               "refs",
+               "refs/tags",
+               "refs/heads",
+               "refs/snap",
+               NULL
+       };
+       const char **p;
+
+       if (!get_sha1_hex(str, sha1))
+               return 0;
+
+       for (p = prefix; *p; p++) {
+               char *pathname = git_path("%s/%.*s", *p, len, str);
+               if (!get_sha1_file(pathname, sha1))
+                       return 0;
+       }
+
+       return -1;
+}
+
+static int get_sha1_1(const char *name, int len, unsigned char *sha1);
+
+static int get_parent(const char *name, int len,
+                     unsigned char *result, int idx)
+{
+       unsigned char sha1[20];
+       int ret = get_sha1_1(name, len, sha1);
+       struct commit *commit;
+       struct commit_list *p;
+
+       if (ret)
+               return ret;
+       commit = lookup_commit_reference(sha1);
+       if (!commit)
+               return -1;
+       if (parse_commit(commit))
+               return -1;
+       if (!idx) {
+               memcpy(result, commit->object.sha1, 20);
+               return 0;
+       }
+       p = commit->parents;
+       while (p) {
+               if (!--idx) {
+                       memcpy(result, p->item->object.sha1, 20);
+                       return 0;
+               }
+               p = p->next;
+       }
+       return -1;
+}
+
+static int get_sha1_1(const char *name, int len, unsigned char *sha1)
+{
+       int parent, ret;
+
+       /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
+       if (len > 2 && name[len-2] == '^' &&
+           name[len-1] >= '0' && name[len-1] <= '9') {
+               parent = name[len-1] - '0';
+               len -= 2;
+       }
+       else if (len > 1 && name[len-1] == '^')
+               parent = 1;
+       else
+               parent = -1;
+
+       if (0 <= parent) {
+               ret = get_parent(name, len-1, sha1, parent);
+               if (!ret)
+                       return 0;
+       }
+       ret = get_sha1_basic(name, len, sha1);
+       if (!ret)
+               return 0;
+       return get_short_sha1(name, sha1);
+}
+
+/*
+ * This is like "get_sha1_basic()", except it allows "sha1 expressions",
+ * notably "xyz^" for "parent of xyz"
+ */
+int get_sha1(const char *name, unsigned char *sha1)
+{
+       return get_sha1_1(name, strlen(name), sha1);
+}