rev-list --boundary
[gitweb.git] / tar-tree.c
index 92035f51d84559478033fe6c801ea18c019360b8..8d9e31c20612f09f641a53b7876591b744eb0cea 100644 (file)
@@ -1,37 +1,23 @@
 /*
- * Copyright (c) 2005 Rene Scharfe
+ * Copyright (c) 2005, 2006 Rene Scharfe
  */
 #include <time.h>
 #include "cache.h"
 #include "diff.h"
 #include "commit.h"
+#include "strbuf.h"
+#include "tar.h"
 
 #define RECORDSIZE     (512)
 #define BLOCKSIZE      (RECORDSIZE * 20)
 
-#define TYPEFLAG_AUTO          '\0'
-#define TYPEFLAG_REG           '0'
-#define TYPEFLAG_LNK           '2'
-#define TYPEFLAG_DIR           '5'
-#define TYPEFLAG_GLOBAL_HEADER 'g'
-#define TYPEFLAG_EXT_HEADER    'x'
-
-#define EXT_HEADER_PATH                1
-#define EXT_HEADER_LINKPATH    2
-
 static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
 
 static char block[BLOCKSIZE];
 static unsigned long offset;
 
-static const char *basedir;
 static time_t archive_time;
 
-struct path_prefix {
-       struct path_prefix *prev;
-       const char *name;
-};
-
 /* tries hard to write, either succeeds or dies in the attempt */
 static void reliable_write(void *buf, unsigned long size)
 {
@@ -119,230 +105,170 @@ static void write_blocked(void *buf, unsigned long size)
        write_if_needed();
 }
 
-static void append_string(char **p, const char *s)
-{
-       unsigned int len = strlen(s);
-       memcpy(*p, s, len);
-       *p += len;
-}
-
-static void append_char(char **p, char c)
-{
-       **p = c;
-       *p += 1;
-}
-
-static void append_path_prefix(char **buffer, struct path_prefix *prefix)
+static void strbuf_append_string(struct strbuf *sb, const char *s)
 {
-       if (!prefix)
-               return;
-       append_path_prefix(buffer, prefix->prev);
-       append_string(buffer, prefix->name);
-       append_char(buffer, '/');
-}
-
-static unsigned int path_prefix_len(struct path_prefix *prefix)
-{
-       if (!prefix)
-               return 0;
-       return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
-}
-
-static void append_path(char **p, int is_dir, const char *basepath,
-                        struct path_prefix *prefix, const char *path)
-{
-       if (basepath) {
-               append_string(p, basepath);
-               append_char(p, '/');
+       int slen = strlen(s);
+       int total = sb->len + slen;
+       if (total > sb->alloc) {
+               sb->buf = xrealloc(sb->buf, total);
+               sb->alloc = total;
        }
-       append_path_prefix(p, prefix);
-       append_string(p, path);
-       if (is_dir)
-               append_char(p, '/');
+       memcpy(sb->buf + sb->len, s, slen);
+       sb->len = total;
 }
 
-static unsigned int path_len(int is_dir, const char *basepath,
-                             struct path_prefix *prefix, const char *path)
-{
-       unsigned int len = 0;
-       if (basepath)
-               len += strlen(basepath) + 1;
-       len += path_prefix_len(prefix) + strlen(path);
-       if (is_dir)
-               len++;
-       return len;
-}
-
-static void append_extended_header_prefix(char **p, unsigned int size,
-                                          const char *keyword)
+/*
+ * pax extended header records have the format "%u %s=%s\n".  %u contains
+ * the size of the whole string (including the %u), the first %s is the
+ * keyword, the second one is the value.  This function constructs such a
+ * string and appends it to a struct strbuf.
+ */
+static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
+                                     const char *value, unsigned int valuelen)
 {
-       int len = sprintf(*p, "%u %s=", size, keyword);
-       *p += len;
-}
+       char *p;
+       int len, total, tmp;
 
-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 = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
+       for (tmp = len; tmp > 9; tmp /= 10)
                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');
-}
+       total = sb->len + len;
+       if (total > sb->alloc) {
+               sb->buf = xrealloc(sb->buf, total);
+               sb->alloc = total;
+       }
 
-static void write_header(const unsigned char *, char, const char *, struct path_prefix *,
-                         const char *, unsigned int, void *, unsigned long);
+       p = sb->buf;
+       p += sprintf(p, "%u %s=", len, keyword);
+       memcpy(p, value, valuelen);
+       p += valuelen;
+       *p = '\n';
+       sb->len = total;
+}
 
-/* stores a pax extended header directly in the block buffer */
-static void write_extended_header(const char *headerfilename, int is_dir,
-                                  unsigned int flags, const char *basepath,
-                                  struct path_prefix *prefix,
-                                  const char *path, unsigned int namelen,
-                                  void *content, unsigned int contentsize)
+static unsigned int ustar_header_chksum(const struct ustar_header *header)
 {
-       char *buffer, *p;
-       unsigned int pathlen, size, linkpathlen = 0;
-
-       size = pathlen = extended_header_len("path", namelen);
-       if (flags & EXT_HEADER_LINKPATH) {
-               linkpathlen = extended_header_len("linkpath", contentsize);
-               size += linkpathlen;
-       }
-       write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
-                    0100600, NULL, size);
-
-       buffer = p = malloc(size);
-       if (!buffer)
-               die("git-tar-tree: %s", strerror(errno));
-       append_extended_header_prefix(&p, pathlen, "path");
-       append_path(&p, is_dir, basepath, prefix, path);
-       append_char(&p, '\n');
-       if (flags & EXT_HEADER_LINKPATH)
-               append_extended_header(&p, "linkpath", content, contentsize);
-       write_blocked(buffer, size);
-       free(buffer);
+       char *p = (char *)header;
+       unsigned int chksum = 0;
+       while (p < header->chksum)
+               chksum += *p++;
+       chksum += sizeof(header->chksum) * ' ';
+       p += sizeof(header->chksum);
+       while (p < (char *)header + sizeof(struct ustar_header))
+               chksum += *p++;
+       return chksum;
 }
 
-static void write_global_extended_header(const unsigned char *sha1)
+static int get_path_prefix(const struct strbuf *path, int maxlen)
 {
-       char *p;
-       unsigned int size;
-
-       size = extended_header_len("comment", 40);
-       write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
-                    "pax_global_header", 0100600, NULL, size);
-
-       p = get_record();
-       append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
-       write_if_needed();
+       int i = path->len;
+       if (i > maxlen)
+               i = maxlen;
+       while (i > 0 && path->buf[i] != '/')
+               i--;
+       return i;
 }
 
-/* stores a ustar header directly in the block buffer */
-static void write_header(const unsigned char *sha1, char typeflag, const char *basepath,
-                         struct path_prefix *prefix, const char *path,
-                         unsigned int mode, void *buffer, unsigned long size)
+static void write_entry(const unsigned char *sha1, struct strbuf *path,
+                        unsigned int mode, void *buffer, unsigned long size)
 {
-       unsigned int namelen; 
-       char *header = NULL;
-       unsigned int checksum = 0;
-       int i;
-       unsigned int ext_header = 0;
-
-       if (typeflag == TYPEFLAG_AUTO) {
-               if (S_ISDIR(mode))
-                       typeflag = TYPEFLAG_DIR;
-               else if (S_ISLNK(mode))
-                       typeflag = TYPEFLAG_LNK;
-               else
-                       typeflag = TYPEFLAG_REG;
-       }
-
-       namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
-       if (namelen > 100)
-               ext_header |= EXT_HEADER_PATH;
-       if (typeflag == TYPEFLAG_LNK && size > 100)
-               ext_header |= EXT_HEADER_LINKPATH;
-
-       /* the extended header must be written before the normal one */
-       if (ext_header) {
-               char headerfilename[51];
-               sprintf(headerfilename, "%s.paxheader", sha1_to_hex(sha1));
-               write_extended_header(headerfilename, S_ISDIR(mode),
-                                     ext_header, basepath, prefix, path,
-                                     namelen, buffer, size);
-       }
-
-       header = get_record();
-
-       if (ext_header) {
-               sprintf(header, "%s.data", sha1_to_hex(sha1));
+       struct ustar_header header;
+       struct strbuf ext_header;
+
+       memset(&header, 0, sizeof(header));
+       ext_header.buf = NULL;
+       ext_header.len = ext_header.alloc = 0;
+
+       if (!sha1) {
+               *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
+               mode = 0100666;
+               strcpy(header.name, "pax_global_header");
+       } else if (!path) {
+               *header.typeflag = TYPEFLAG_EXT_HEADER;
+               mode = 0100666;
+               sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
        } else {
-               char *p = header;
-               append_path(&p, S_ISDIR(mode), basepath, prefix, path);
+               if (S_ISDIR(mode)) {
+                       *header.typeflag = TYPEFLAG_DIR;
+                       mode |= 0777;
+               } else if (S_ISLNK(mode)) {
+                       *header.typeflag = TYPEFLAG_LNK;
+                       mode |= 0777;
+               } else if (S_ISREG(mode)) {
+                       *header.typeflag = TYPEFLAG_REG;
+                       mode |= (mode & 0100) ? 0777 : 0666;
+               } else {
+                       error("unsupported file mode: 0%o (SHA1: %s)",
+                             mode, sha1_to_hex(sha1));
+                       return;
+               }
+               if (path->len > sizeof(header.name)) {
+                       int plen = get_path_prefix(path, sizeof(header.prefix));
+                       int rest = path->len - plen - 1;
+                       if (plen > 0 && rest <= sizeof(header.name)) {
+                               memcpy(header.prefix, path->buf, plen);
+                               memcpy(header.name, path->buf + plen + 1, rest);
+                       } else {
+                               sprintf(header.name, "%s.data",
+                                       sha1_to_hex(sha1));
+                               strbuf_append_ext_header(&ext_header, "path",
+                                                        path->buf, path->len);
+                       }
+               } else
+                       memcpy(header.name, path->buf, path->len);
        }
 
-       if (typeflag == TYPEFLAG_LNK) {
-               if (ext_header & EXT_HEADER_LINKPATH) {
-                       sprintf(&header[157], "see %s.paxheader",
+       if (S_ISLNK(mode) && buffer) {
+               if (size > sizeof(header.linkname)) {
+                       sprintf(header.linkname, "see %s.paxheader",
                                sha1_to_hex(sha1));
-               } else {
-                       if (buffer)
-                               strncpy(&header[157], buffer, size);
-               }
+                       strbuf_append_ext_header(&ext_header, "linkpath",
+                                                buffer, size);
+               } else
+                       memcpy(header.linkname, buffer, size);
        }
 
-       if (S_ISDIR(mode))
-               mode |= 0777;
-       else if (S_ISREG(mode))
-               mode |= (mode & 0100) ? 0777 : 0666;
-       else if (S_ISLNK(mode))
-               mode |= 0777;
-       sprintf(&header[100], "%07o", mode & 07777);
+       sprintf(header.mode, "%07o", mode & 07777);
+       sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
+       sprintf(header.mtime, "%011lo", archive_time);
 
        /* XXX: should we provide more meaningful info here? */
-       sprintf(&header[108], "%07o", 0);       /* uid */
-       sprintf(&header[116], "%07o", 0);       /* gid */
-       strncpy(&header[265], "git", 31);       /* uname */
-       strncpy(&header[297], "git", 31);       /* gname */
-
-       if (S_ISDIR(mode) || S_ISLNK(mode))
-               size = 0;
-       sprintf(&header[124], "%011lo", size);
-       sprintf(&header[136], "%011lo", archive_time);
+       sprintf(header.uid, "%07o", 0);
+       sprintf(header.gid, "%07o", 0);
+       strncpy(header.uname, "git", 31);
+       strncpy(header.gname, "git", 31);
+       sprintf(header.devmajor, "%07o", 0);
+       sprintf(header.devminor, "%07o", 0);
 
-       header[156] = typeflag;
+       memcpy(header.magic, "ustar", 6);
+       memcpy(header.version, "00", 2);
 
-       memcpy(&header[257], "ustar", 6);
-       memcpy(&header[263], "00", 2);
+       sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 
-       sprintf(&header[329], "%07o", 0);       /* devmajor */
-       sprintf(&header[337], "%07o", 0);       /* devminor */
-
-       memset(&header[148], ' ', 8);
-       for (i = 0; i < RECORDSIZE; i++)
-               checksum += header[i];
-       sprintf(&header[148], "%07o", checksum & 0x1fffff);
+       if (ext_header.len > 0) {
+               write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
+               free(ext_header.buf);
+       }
+       write_blocked(&header, sizeof(header));
+       if (S_ISREG(mode) && buffer && size > 0)
+               write_blocked(buffer, size);
+}
 
-       write_if_needed();
+static void write_global_extended_header(const unsigned char *sha1)
+{
+       struct strbuf ext_header;
+       ext_header.buf = NULL;
+       ext_header.len = ext_header.alloc = 0;
+       strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
+       write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
+       free(ext_header.buf);
 }
 
-static void traverse_tree(struct tree_desc *tree,
-                         struct path_prefix *prefix)
+static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
 {
-       struct path_prefix this_prefix;
-       this_prefix.prev = prefix;
+       int pathlen = path->len;
 
        while (tree->size) {
                const char *name;
@@ -358,16 +284,19 @@ static void traverse_tree(struct tree_desc *tree,
                eltbuf = read_sha1_file(sha1, elttype, &eltsize);
                if (!eltbuf)
                        die("cannot read %s", sha1_to_hex(sha1));
-               write_header(sha1, TYPEFLAG_AUTO, basedir, 
-                            prefix, name, mode, eltbuf, eltsize);
+
+               path->len = pathlen;
+               strbuf_append_string(path, name);
+               if (S_ISDIR(mode))
+                       strbuf_append_string(path, "/");
+
+               write_entry(sha1, path, mode, eltbuf, eltsize);
+
                if (S_ISDIR(mode)) {
                        struct tree_desc subtree;
                        subtree.buf = eltbuf;
                        subtree.size = eltsize;
-                       this_prefix.name = name;
-                       traverse_tree(&subtree, &this_prefix);
-               } else if (!S_ISLNK(mode)) {
-                       write_blocked(eltbuf, eltsize);
+                       traverse_tree(&subtree, path);
                }
                free(eltbuf);
        }
@@ -375,16 +304,22 @@ static void traverse_tree(struct tree_desc *tree,
 
 int main(int argc, char **argv)
 {
-       unsigned char sha1[20];
+       unsigned char sha1[20], tree_sha1[20];
        struct commit *commit;
        struct tree_desc tree;
+       struct strbuf current_path;
+
+       current_path.buf = xmalloc(PATH_MAX);
+       current_path.alloc = PATH_MAX;
+       current_path.len = current_path.eof = 0;
 
        setup_git_directory();
        git_config(git_default_config);
 
        switch (argc) {
        case 3:
-               basedir = argv[2];
+               strbuf_append_string(&current_path, argv[2]);
+               strbuf_append_string(&current_path, "/");
                /* FALLTHROUGH */
        case 2:
                if (get_sha1(argv[1], sha1) < 0)
@@ -398,17 +333,19 @@ int main(int argc, char **argv)
        if (commit) {
                write_global_extended_header(commit->object.sha1);
                archive_time = commit->date;
-       }
-       tree.buf = read_object_with_reference(sha1, "tree", &tree.size, NULL);
+       } else
+               archive_time = time(NULL);
+
+       tree.buf = read_object_with_reference(sha1, "tree", &tree.size,
+                                             tree_sha1);
        if (!tree.buf)
                die("not a reference to a tag, commit or tree object: %s",
                    sha1_to_hex(sha1));
-       if (!archive_time)
-               archive_time = time(NULL);
-       if (basedir)
-               write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
-                       basedir, 040777, NULL, 0);
-       traverse_tree(&tree, NULL);
+
+       if (current_path.len > 0)
+               write_entry(tree_sha1, &current_path, 040777, NULL, 0);
+       traverse_tree(&tree, &current_path);
        write_trailer();
+       free(current_path.buf);
        return 0;
 }