[PATCH] git-tar-tree: add extended header helpers

[git.git] / tar-tree.c

diff --git a/tar-tree.c b/tar-tree.c
index ea7ea91..277c882 100644 (file)
--- a/tar-tree.c
+++ b/tar-tree.c
@@ -4,6 +4,12 @@
 #define RECORDSIZE     (512)
 #define BLOCKSIZE      (RECORDSIZE * 20)
 
+#define TYPEFLAG_AUTO          '\0'
+#define TYPEFLAG_REG           '0'
+#define TYPEFLAG_DIR           '5'
+#define TYPEFLAG_GLOBAL_HEADER 'g'
+#define TYPEFLAG_EXT_HEADER    'x'
+
 static const char *tar_tree_usage = "tar-tree <key> [basedir]";
 
 static char block[BLOCKSIZE];
@@ -45,6 +51,15 @@ static void write_if_needed(void)
        }
 }
 
+/* acquire the next record from the buffer; user must call write_if_needed() */
+static char *get_record(void)
+{
+       char *p = block + offset;
+       memset(p, 0, RECORDSIZE);
+       offset += RECORDSIZE;
+       return p;
+}
+
 /*
  * The end of tar archives is marked by 1024 nul bytes and after that
  * follows the rest of the block (if any).
@@ -113,12 +128,6 @@ static void append_char(char **p, char c)
        *p += 1;
 }
 
-static void append_long(char **p, long n)
-{
-       int len = sprintf(*p, "%ld", n);
-       *p += len;
-}
-
 static void append_path_prefix(char **buffer, struct path_prefix *prefix)
 {
        if (!prefix)
@@ -160,6 +169,35 @@ static unsigned int path_len(int is_dir, const char *basepath,
        return len;
 }
 
+static void append_extended_header_prefix(char **p, unsigned int size,
+                                          const char *keyword)
+{
+       int len = sprintf(*p, "%u %s=", size, keyword);
+       *p += len;
+}
+
+static unsigned int extended_header_len(const char *keyword,
+                                        unsigned int valuelen)
+{
+       /* "%u %s=%s\n" */
+       unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
+       if (len > 9)
+               len++;
+       if (len > 99)
+               len++;
+       return len;
+}
+
+static void append_extended_header(char **p, const char *keyword,
+                                   const char *value, unsigned int len)
+{
+       unsigned int size = extended_header_len(keyword, len);
+       append_extended_header_prefix(p, size, keyword);
+       memcpy(*p, value, len);
+       *p += len;
+       append_char(p, '\n');
+}
+
 static void write_header(const char *, char, const char *, struct path_prefix *,
                          const char *, unsigned int, unsigned long);
 
@@ -170,19 +208,16 @@ static void write_extended_header(const char *headerfilename, int is_dir,
                                   const char *path, unsigned int namelen)
 {
        char *p;
-       unsigned int size = 1 + 6 + namelen + 1;
-       if (size > 9)
-               size++;
-       if (size > 99)
-               size++;
+       unsigned int pathlen, size;
+
+       size = pathlen = extended_header_len("path", namelen);
        if (size > RECORDSIZE)
                die("tar-tree: extended header too big, wtf?");
-       write_header(NULL, 'x', NULL, NULL, headerfilename, 0100600, size);
-       p = block + offset;
-       memset(p, 0, RECORDSIZE);
-       offset += RECORDSIZE;
-       append_long(&p, size);
-       append_string(&p, " path=");
+       write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
+                    0100600, size);
+
+       p = get_record();
+       append_extended_header_prefix(&p, pathlen, "path");
        append_path(&p, is_dir, basepath, prefix, path);
        append_char(&p, '\n');
        write_if_needed();
@@ -191,14 +226,14 @@ static void write_extended_header(const char *headerfilename, int is_dir,
 static void write_global_extended_header(const char *sha1)
 {
        char *p;
-       write_header(NULL, 'g', NULL, NULL, "pax_global_header", 0, 52);
-       p = block + offset;
-       memset(p, 0, RECORDSIZE);
-       offset += RECORDSIZE;
-       append_long(&p, 52);    /* 2 + 9 + 40 + 1 */
-       append_string(&p, " comment=");
-       append_string(&p, sha1_to_hex(sha1));
-       append_char(&p, '\n');
+       unsigned int size;
+
+       size = extended_header_len("comment", 40);
+       write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
+                    "pax_global_header", 0100600, size);
+
+       p = get_record();
+       append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
        write_if_needed();
 }
 
@@ -212,6 +247,13 @@ static void write_header(const char *sha1, char typeflag, const char *basepath,
        unsigned int checksum = 0;
        int i;
 
+       if (typeflag == TYPEFLAG_AUTO) {
+               if (S_ISDIR(mode))
+                       typeflag = TYPEFLAG_DIR;
+               else
+                       typeflag = TYPEFLAG_REG;
+       }
+
        namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
        if (namelen > 500) {
                die("tar-tree: name too log of object %s\n", sha1_to_hex(sha1));
@@ -223,15 +265,10 @@ static void write_header(const char *sha1, char typeflag, const char *basepath,
                write_extended_header(headerfilename, S_ISDIR(mode), basepath,
                                      prefix, path, namelen);
 
-               header = block + offset;
-               memset(header, 0, RECORDSIZE);
-               offset += RECORDSIZE;
+               header = get_record();
                sprintf(header, "%s.data", sha1_hex);
        } else {
-               header = block + offset;
-               memset(header, 0, RECORDSIZE);
-               offset += RECORDSIZE;
-               p = header;
+               p = header = get_record();
                append_path(&p, S_ISDIR(mode), basepath, prefix, path);
        }
 
@@ -287,8 +324,8 @@ static void traverse_tree(void *buffer, unsigned long size,
                eltbuf = read_sha1_file(sha1, elttype, &eltsize);
                if (!eltbuf)
                        die("cannot read %s", sha1_to_hex(sha1));
-               write_header(sha1, S_ISDIR(mode) ? '5' : '0', basedir,
-                            prefix, path, mode, eltsize);
+               write_header(sha1, TYPEFLAG_AUTO, basedir, prefix, path,
+                            mode, eltsize);
                if (!strcmp(elttype, "tree")) {
                        this_prefix.name = path;
                        traverse_tree(eltbuf, eltsize, &this_prefix);
@@ -338,7 +375,7 @@ int main(int argc, char **argv)
                basedir = argv[2];
                /* FALLTHROUGH */
        case 2:
-               if (get_sha1_hex(argv[1], sha1) < 0)
+               if (get_sha1(argv[1], sha1) < 0)
                        usage(tar_tree_usage);
                break;
        default:
@@ -362,7 +399,7 @@ int main(int argc, char **argv)
        if (!archive_time)
                archive_time = time(NULL);
        if (basedir)
-               write_header("0", '5', NULL, NULL, basedir, 040755, 0);
+               write_header("0", TYPEFLAG_DIR, NULL, NULL, basedir, 040755, 0);
        traverse_tree(buffer, size, NULL);
        free(buffer);
        write_trailer();