diff options
Diffstat (limited to 'object-file-convert.c')
| -rw-r--r-- | object-file-convert.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/object-file-convert.c b/object-file-convert.c new file mode 100644 index 0000000000..4f6189095b --- /dev/null +++ b/object-file-convert.c @@ -0,0 +1,277 @@ +#include "git-compat-util.h" +#include "gettext.h" +#include "strbuf.h" +#include "hex.h" +#include "repository.h" +#include "hash-ll.h" +#include "hash.h" +#include "object.h" +#include "loose.h" +#include "commit.h" +#include "gpg-interface.h" +#include "object-file-convert.h" + +int repo_oid_to_algop(struct repository *repo, const struct object_id *src, + const struct git_hash_algo *to, struct object_id *dest) +{ + /* + * If the source algorithm is not set, then we're using the + * default hash algorithm for that object. + */ + const struct git_hash_algo *from = + src->algo ? &hash_algos[src->algo] : repo->hash_algo; + + if (from == to) { + if (src != dest) + oidcpy(dest, src); + return 0; + } + if (repo_loose_object_map_oid(repo, src, to, dest)) { + /* + * We may have loaded the object map at repo initialization but + * another process (perhaps upstream of a pipe from us) may have + * written a new object into the map. If the object is missing, + * let's reload the map to see if the object has appeared. + */ + repo_read_loose_object_map(repo); + if (repo_loose_object_map_oid(repo, src, to, dest)) + return -1; + } + return 0; +} + +static int decode_tree_entry_raw(struct object_id *oid, const char **path, + size_t *len, const struct git_hash_algo *algo, + const char *buf, unsigned long size) +{ + uint16_t mode; + const unsigned hashsz = algo->rawsz; + + if (size < hashsz + 3 || buf[size - (hashsz + 1)]) { + return -1; + } + + *path = parse_mode(buf, &mode); + if (!*path || !**path) + return -1; + *len = strlen(*path) + 1; + + oidread_algop(oid, (const unsigned char *)*path + *len, algo); + return 0; +} + +static int convert_tree_object(struct strbuf *out, + const struct git_hash_algo *from, + const struct git_hash_algo *to, + const char *buffer, size_t size) +{ + const char *p = buffer, *end = buffer + size; + + while (p < end) { + struct object_id entry_oid, mapped_oid; + const char *path = NULL; + size_t pathlen; + + if (decode_tree_entry_raw(&entry_oid, &path, &pathlen, from, p, + end - p)) + return error(_("failed to decode tree entry")); + if (repo_oid_to_algop(the_repository, &entry_oid, to, &mapped_oid)) + return error(_("failed to map tree entry for %s"), oid_to_hex(&entry_oid)); + strbuf_add(out, p, path - p); + strbuf_add(out, path, pathlen); + strbuf_add(out, mapped_oid.hash, to->rawsz); + p = path + pathlen + from->rawsz; + } + return 0; +} + +static int convert_tag_object(struct strbuf *out, + const struct git_hash_algo *from, + const struct git_hash_algo *to, + const char *buffer, size_t size) +{ + struct strbuf payload = STRBUF_INIT, oursig = STRBUF_INIT, othersig = STRBUF_INIT; + const int entry_len = from->hexsz + 7; + size_t payload_size; + struct object_id oid, mapped_oid; + const char *p; + + /* Consume the object line */ + if ((entry_len >= size) || + memcmp(buffer, "object ", 7) || buffer[entry_len] != '\n') + return error("bogus tag object"); + if (parse_oid_hex_algop(buffer + 7, &oid, &p, from) < 0) + return error("bad tag object ID"); + if (repo_oid_to_algop(the_repository, &oid, to, &mapped_oid)) + return error("unable to map tree %s in tag object", + oid_to_hex(&oid)); + size -= ((p + 1) - buffer); + buffer = p + 1; + + /* Is there a signature for our algorithm? */ + payload_size = parse_signed_buffer(buffer, size); + if (payload_size != size) { + /* Yes, there is. */ + strbuf_add(&oursig, buffer + payload_size, size - payload_size); + } + + /* Now, is there a signature for the other algorithm? */ + parse_buffer_signed_by_header(buffer, payload_size, &payload, &othersig, to); + /* + * Our payload is now in payload and we may have up to two signatrures + * in oursig and othersig. + */ + + /* Add some slop for longer signature header in the new algorithm. */ + strbuf_grow(out, (7 + to->hexsz + 1) + size + 7); + strbuf_addf(out, "object %s\n", oid_to_hex(&mapped_oid)); + strbuf_addbuf(out, &payload); + if (oursig.len) + add_header_signature(out, &oursig, from); + strbuf_addbuf(out, &othersig); + + strbuf_release(&payload); + strbuf_release(&othersig); + strbuf_release(&oursig); + return 0; +} + +static int convert_commit_object(struct strbuf *out, + const struct git_hash_algo *from, + const struct git_hash_algo *to, + const char *buffer, size_t size) +{ + const char *tail = buffer; + const char *bufptr = buffer; + const int tree_entry_len = from->hexsz + 5; + const int parent_entry_len = from->hexsz + 7; + struct object_id oid, mapped_oid; + const char *p, *eol; + + tail += size; + + while ((bufptr < tail) && (*bufptr != '\n')) { + eol = memchr(bufptr, '\n', tail - bufptr); + if (!eol) + return error(_("bad %s in commit"), "line"); + + if (((bufptr + 5) < eol) && !memcmp(bufptr, "tree ", 5)) + { + if (((bufptr + tree_entry_len) != eol) || + parse_oid_hex_algop(bufptr + 5, &oid, &p, from) || + (p != eol)) + return error(_("bad %s in commit"), "tree"); + + if (repo_oid_to_algop(the_repository, &oid, to, &mapped_oid)) + return error(_("unable to map %s %s in commit object"), + "tree", oid_to_hex(&oid)); + strbuf_addf(out, "tree %s\n", oid_to_hex(&mapped_oid)); + } + else if (((bufptr + 7) < eol) && !memcmp(bufptr, "parent ", 7)) + { + if (((bufptr + parent_entry_len) != eol) || + parse_oid_hex_algop(bufptr + 7, &oid, &p, from) || + (p != eol)) + return error(_("bad %s in commit"), "parent"); + + if (repo_oid_to_algop(the_repository, &oid, to, &mapped_oid)) + return error(_("unable to map %s %s in commit object"), + "parent", oid_to_hex(&oid)); + + strbuf_addf(out, "parent %s\n", oid_to_hex(&mapped_oid)); + } + else if (((bufptr + 9) < eol) && !memcmp(bufptr, "mergetag ", 9)) + { + struct strbuf tag = STRBUF_INIT, new_tag = STRBUF_INIT; + + /* Recover the tag object from the mergetag */ + strbuf_add(&tag, bufptr + 9, (eol - (bufptr + 9)) + 1); + + bufptr = eol + 1; + while ((bufptr < tail) && (*bufptr == ' ')) { + eol = memchr(bufptr, '\n', tail - bufptr); + if (!eol) { + strbuf_release(&tag); + return error(_("bad %s in commit"), "mergetag continuation"); + } + strbuf_add(&tag, bufptr + 1, (eol - (bufptr + 1)) + 1); + bufptr = eol + 1; + } + + /* Compute the new tag object */ + if (convert_tag_object(&new_tag, from, to, tag.buf, tag.len)) { + strbuf_release(&tag); + strbuf_release(&new_tag); + return -1; + } + + /* Write the new mergetag */ + strbuf_addstr(out, "mergetag"); + strbuf_add_lines(out, " ", new_tag.buf, new_tag.len); + strbuf_release(&tag); + strbuf_release(&new_tag); + } + else if (((bufptr + 7) < tail) && !memcmp(bufptr, "author ", 7)) + strbuf_add(out, bufptr, (eol - bufptr) + 1); + else if (((bufptr + 10) < tail) && !memcmp(bufptr, "committer ", 10)) + strbuf_add(out, bufptr, (eol - bufptr) + 1); + else if (((bufptr + 9) < tail) && !memcmp(bufptr, "encoding ", 9)) + strbuf_add(out, bufptr, (eol - bufptr) + 1); + else if (((bufptr + 6) < tail) && !memcmp(bufptr, "gpgsig", 6)) + strbuf_add(out, bufptr, (eol - bufptr) + 1); + else { + /* Unknown line fail it might embed an oid */ + return -1; + } + /* Consume any trailing continuation lines */ + bufptr = eol + 1; + while ((bufptr < tail) && (*bufptr == ' ')) { + eol = memchr(bufptr, '\n', tail - bufptr); + if (!eol) + return error(_("bad %s in commit"), "continuation"); + strbuf_add(out, bufptr, (eol - bufptr) + 1); + bufptr = eol + 1; + } + } + if (bufptr < tail) + strbuf_add(out, bufptr, tail - bufptr); + return 0; +} + +int convert_object_file(struct strbuf *outbuf, + const struct git_hash_algo *from, + const struct git_hash_algo *to, + const void *buf, size_t len, + enum object_type type, + int gentle) +{ + int ret; + + /* Don't call this function when no conversion is necessary */ + if ((from == to) || (type == OBJ_BLOB)) + BUG("Refusing noop object file conversion"); + + switch (type) { + case OBJ_COMMIT: + ret = convert_commit_object(outbuf, from, to, buf, len); + break; + case OBJ_TREE: + ret = convert_tree_object(outbuf, from, to, buf, len); + break; + case OBJ_TAG: + ret = convert_tag_object(outbuf, from, to, buf, len); + break; + default: + /* Not implemented yet, so fail. */ + ret = -1; + break; + } + if (!ret) + return 0; + if (gentle) { + strbuf_release(outbuf); + return ret; + } + die(_("Failed to convert object from %s to %s"), + from->name, to->name); +} |