mirror of
https://github.com/git/git.git
synced 2024-11-26 03:14:50 +08:00
a1e920a0a7
We have some tricky checks in fsck that rely on a side effect of require_end_of_header(), and would otherwise easily run outside non-NUL-terminated buffers. This is a bit brittle, so let's make sure that only NUL-terminated buffers are passed around to begin with. Jeff "Peff" King contributed the detailed analysis which call paths are involved and pointed out that we also have to patch the get_data() function in unpack-objects.c, which is what Johannes "Dscho" Schindelin implemented. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Analyzed-by: Jeff King <peff@peff.net> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
575 lines
13 KiB
C
575 lines
13 KiB
C
#include "builtin.h"
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#include "cache.h"
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#include "object.h"
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#include "delta.h"
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#include "pack.h"
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#include "blob.h"
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#include "commit.h"
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#include "tag.h"
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#include "tree.h"
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#include "tree-walk.h"
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#include "progress.h"
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#include "decorate.h"
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#include "fsck.h"
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static int dry_run, quiet, recover, has_errors, strict;
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static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict] < pack-file";
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/* We always read in 4kB chunks. */
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static unsigned char buffer[4096];
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static unsigned int offset, len;
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static off_t consumed_bytes;
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static git_SHA_CTX ctx;
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/*
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* When running under --strict mode, objects whose reachability are
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* suspect are kept in core without getting written in the object
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* store.
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*/
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struct obj_buffer {
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char *buffer;
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unsigned long size;
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};
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static struct decoration obj_decorate;
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static struct obj_buffer *lookup_object_buffer(struct object *base)
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{
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return lookup_decoration(&obj_decorate, base);
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}
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static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
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{
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struct obj_buffer *obj;
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obj = xcalloc(1, sizeof(struct obj_buffer));
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obj->buffer = buffer;
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obj->size = size;
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if (add_decoration(&obj_decorate, object, obj))
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die("object %s tried to add buffer twice!", sha1_to_hex(object->sha1));
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}
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/*
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* Make sure at least "min" bytes are available in the buffer, and
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* return the pointer to the buffer.
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*/
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static void *fill(int min)
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{
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if (min <= len)
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return buffer + offset;
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if (min > sizeof(buffer))
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die("cannot fill %d bytes", min);
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if (offset) {
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git_SHA1_Update(&ctx, buffer, offset);
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memmove(buffer, buffer + offset, len);
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offset = 0;
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}
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do {
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ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
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if (ret <= 0) {
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if (!ret)
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die("early EOF");
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die_errno("read error on input");
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}
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len += ret;
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} while (len < min);
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return buffer;
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}
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static void use(int bytes)
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{
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if (bytes > len)
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die("used more bytes than were available");
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len -= bytes;
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offset += bytes;
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/* make sure off_t is sufficiently large not to wrap */
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if (signed_add_overflows(consumed_bytes, bytes))
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die("pack too large for current definition of off_t");
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consumed_bytes += bytes;
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}
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static void *get_data(unsigned long size)
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{
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git_zstream stream;
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void *buf = xmallocz(size);
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memset(&stream, 0, sizeof(stream));
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stream.next_out = buf;
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stream.avail_out = size;
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stream.next_in = fill(1);
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stream.avail_in = len;
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git_inflate_init(&stream);
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for (;;) {
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int ret = git_inflate(&stream, 0);
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use(len - stream.avail_in);
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if (stream.total_out == size && ret == Z_STREAM_END)
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break;
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if (ret != Z_OK) {
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error("inflate returned %d", ret);
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free(buf);
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buf = NULL;
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if (!recover)
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exit(1);
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has_errors = 1;
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break;
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}
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stream.next_in = fill(1);
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stream.avail_in = len;
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}
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git_inflate_end(&stream);
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return buf;
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}
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struct delta_info {
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unsigned char base_sha1[20];
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unsigned nr;
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off_t base_offset;
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unsigned long size;
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void *delta;
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struct delta_info *next;
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};
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static struct delta_info *delta_list;
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static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1,
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off_t base_offset,
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void *delta, unsigned long size)
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{
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struct delta_info *info = xmalloc(sizeof(*info));
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hashcpy(info->base_sha1, base_sha1);
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info->base_offset = base_offset;
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info->size = size;
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info->delta = delta;
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info->nr = nr;
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info->next = delta_list;
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delta_list = info;
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}
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struct obj_info {
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off_t offset;
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unsigned char sha1[20];
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struct object *obj;
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};
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#define FLAG_OPEN (1u<<20)
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#define FLAG_WRITTEN (1u<<21)
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static struct obj_info *obj_list;
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static unsigned nr_objects;
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/*
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* Called only from check_object() after it verified this object
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* is Ok.
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*/
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static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
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{
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unsigned char sha1[20];
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if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type), sha1) < 0)
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die("failed to write object %s", sha1_to_hex(obj->sha1));
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obj->flags |= FLAG_WRITTEN;
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}
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/*
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* At the very end of the processing, write_rest() scans the objects
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* that have reachability requirements and calls this function.
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* Verify its reachability and validity recursively and write it out.
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*/
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static int check_object(struct object *obj, int type, void *data)
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{
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struct obj_buffer *obj_buf;
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if (!obj)
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return 1;
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if (obj->flags & FLAG_WRITTEN)
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return 0;
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if (type != OBJ_ANY && obj->type != type)
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die("object type mismatch");
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if (!(obj->flags & FLAG_OPEN)) {
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unsigned long size;
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int type = sha1_object_info(obj->sha1, &size);
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if (type != obj->type || type <= 0)
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die("object of unexpected type");
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obj->flags |= FLAG_WRITTEN;
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return 0;
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}
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obj_buf = lookup_object_buffer(obj);
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if (!obj_buf)
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die("Whoops! Cannot find object '%s'", sha1_to_hex(obj->sha1));
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if (fsck_object(obj, obj_buf->buffer, obj_buf->size, 1,
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fsck_error_function))
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die("Error in object");
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if (fsck_walk(obj, check_object, NULL))
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die("Error on reachable objects of %s", sha1_to_hex(obj->sha1));
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write_cached_object(obj, obj_buf);
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return 0;
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}
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static void write_rest(void)
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{
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unsigned i;
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for (i = 0; i < nr_objects; i++) {
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if (obj_list[i].obj)
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check_object(obj_list[i].obj, OBJ_ANY, NULL);
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}
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}
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static void added_object(unsigned nr, enum object_type type,
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void *data, unsigned long size);
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/*
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* Write out nr-th object from the list, now we know the contents
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* of it. Under --strict, this buffers structured objects in-core,
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* to be checked at the end.
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*/
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static void write_object(unsigned nr, enum object_type type,
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void *buf, unsigned long size)
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{
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if (!strict) {
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if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
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die("failed to write object");
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added_object(nr, type, buf, size);
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free(buf);
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obj_list[nr].obj = NULL;
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} else if (type == OBJ_BLOB) {
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struct blob *blob;
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if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
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die("failed to write object");
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added_object(nr, type, buf, size);
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free(buf);
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blob = lookup_blob(obj_list[nr].sha1);
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if (blob)
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blob->object.flags |= FLAG_WRITTEN;
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else
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die("invalid blob object");
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obj_list[nr].obj = NULL;
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} else {
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struct object *obj;
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int eaten;
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hash_sha1_file(buf, size, typename(type), obj_list[nr].sha1);
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added_object(nr, type, buf, size);
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obj = parse_object_buffer(obj_list[nr].sha1, type, size, buf, &eaten);
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if (!obj)
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die("invalid %s", typename(type));
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add_object_buffer(obj, buf, size);
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obj->flags |= FLAG_OPEN;
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obj_list[nr].obj = obj;
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}
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}
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static void resolve_delta(unsigned nr, enum object_type type,
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void *base, unsigned long base_size,
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void *delta, unsigned long delta_size)
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{
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void *result;
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unsigned long result_size;
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result = patch_delta(base, base_size,
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delta, delta_size,
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&result_size);
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if (!result)
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die("failed to apply delta");
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free(delta);
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write_object(nr, type, result, result_size);
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}
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/*
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* We now know the contents of an object (which is nr-th in the pack);
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* resolve all the deltified objects that are based on it.
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*/
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static void added_object(unsigned nr, enum object_type type,
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void *data, unsigned long size)
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{
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struct delta_info **p = &delta_list;
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struct delta_info *info;
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while ((info = *p) != NULL) {
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if (!hashcmp(info->base_sha1, obj_list[nr].sha1) ||
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info->base_offset == obj_list[nr].offset) {
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*p = info->next;
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p = &delta_list;
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resolve_delta(info->nr, type, data, size,
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info->delta, info->size);
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free(info);
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continue;
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}
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p = &info->next;
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}
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}
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static void unpack_non_delta_entry(enum object_type type, unsigned long size,
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unsigned nr)
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{
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void *buf = get_data(size);
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if (!dry_run && buf)
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write_object(nr, type, buf, size);
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else
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free(buf);
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}
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static int resolve_against_held(unsigned nr, const unsigned char *base,
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void *delta_data, unsigned long delta_size)
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{
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struct object *obj;
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struct obj_buffer *obj_buffer;
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obj = lookup_object(base);
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if (!obj)
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return 0;
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obj_buffer = lookup_object_buffer(obj);
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if (!obj_buffer)
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return 0;
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resolve_delta(nr, obj->type, obj_buffer->buffer,
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obj_buffer->size, delta_data, delta_size);
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return 1;
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}
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static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
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unsigned nr)
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{
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void *delta_data, *base;
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unsigned long base_size;
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unsigned char base_sha1[20];
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if (type == OBJ_REF_DELTA) {
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hashcpy(base_sha1, fill(20));
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use(20);
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delta_data = get_data(delta_size);
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if (dry_run || !delta_data) {
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free(delta_data);
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return;
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}
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if (has_sha1_file(base_sha1))
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; /* Ok we have this one */
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else if (resolve_against_held(nr, base_sha1,
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delta_data, delta_size))
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return; /* we are done */
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else {
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/* cannot resolve yet --- queue it */
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hashcpy(obj_list[nr].sha1, null_sha1);
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add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size);
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return;
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}
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} else {
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unsigned base_found = 0;
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unsigned char *pack, c;
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off_t base_offset;
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unsigned lo, mid, hi;
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pack = fill(1);
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c = *pack;
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use(1);
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base_offset = c & 127;
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while (c & 128) {
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base_offset += 1;
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if (!base_offset || MSB(base_offset, 7))
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die("offset value overflow for delta base object");
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pack = fill(1);
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c = *pack;
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use(1);
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base_offset = (base_offset << 7) + (c & 127);
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}
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base_offset = obj_list[nr].offset - base_offset;
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if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
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die("offset value out of bound for delta base object");
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delta_data = get_data(delta_size);
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if (dry_run || !delta_data) {
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free(delta_data);
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return;
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}
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lo = 0;
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hi = nr;
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while (lo < hi) {
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mid = (lo + hi)/2;
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if (base_offset < obj_list[mid].offset) {
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hi = mid;
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} else if (base_offset > obj_list[mid].offset) {
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lo = mid + 1;
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} else {
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hashcpy(base_sha1, obj_list[mid].sha1);
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base_found = !is_null_sha1(base_sha1);
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break;
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}
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}
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if (!base_found) {
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/*
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* The delta base object is itself a delta that
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* has not been resolved yet.
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*/
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hashcpy(obj_list[nr].sha1, null_sha1);
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add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size);
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return;
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}
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}
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if (resolve_against_held(nr, base_sha1, delta_data, delta_size))
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return;
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base = read_sha1_file(base_sha1, &type, &base_size);
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if (!base) {
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error("failed to read delta-pack base object %s",
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sha1_to_hex(base_sha1));
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if (!recover)
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exit(1);
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has_errors = 1;
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return;
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}
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resolve_delta(nr, type, base, base_size, delta_data, delta_size);
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free(base);
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}
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static void unpack_one(unsigned nr)
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{
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unsigned shift;
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unsigned char *pack;
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unsigned long size, c;
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enum object_type type;
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obj_list[nr].offset = consumed_bytes;
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pack = fill(1);
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c = *pack;
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use(1);
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type = (c >> 4) & 7;
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size = (c & 15);
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shift = 4;
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while (c & 0x80) {
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pack = fill(1);
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c = *pack;
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use(1);
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size += (c & 0x7f) << shift;
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shift += 7;
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}
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switch (type) {
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case OBJ_COMMIT:
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case OBJ_TREE:
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case OBJ_BLOB:
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case OBJ_TAG:
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unpack_non_delta_entry(type, size, nr);
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return;
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case OBJ_REF_DELTA:
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case OBJ_OFS_DELTA:
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unpack_delta_entry(type, size, nr);
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return;
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default:
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error("bad object type %d", type);
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has_errors = 1;
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if (recover)
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return;
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exit(1);
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}
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}
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static void unpack_all(void)
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{
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int i;
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struct progress *progress = NULL;
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struct pack_header *hdr = fill(sizeof(struct pack_header));
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nr_objects = ntohl(hdr->hdr_entries);
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if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
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die("bad pack file");
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if (!pack_version_ok(hdr->hdr_version))
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die("unknown pack file version %"PRIu32,
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ntohl(hdr->hdr_version));
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use(sizeof(struct pack_header));
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if (!quiet)
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progress = start_progress(_("Unpacking objects"), nr_objects);
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obj_list = xcalloc(nr_objects, sizeof(*obj_list));
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for (i = 0; i < nr_objects; i++) {
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unpack_one(i);
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display_progress(progress, i + 1);
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}
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stop_progress(&progress);
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if (delta_list)
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die("unresolved deltas left after unpacking");
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}
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int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
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{
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int i;
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unsigned char sha1[20];
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check_replace_refs = 0;
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git_config(git_default_config, NULL);
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quiet = !isatty(2);
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for (i = 1 ; i < argc; i++) {
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const char *arg = argv[i];
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if (*arg == '-') {
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if (!strcmp(arg, "-n")) {
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dry_run = 1;
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continue;
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}
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if (!strcmp(arg, "-q")) {
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quiet = 1;
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continue;
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}
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if (!strcmp(arg, "-r")) {
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recover = 1;
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continue;
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}
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if (!strcmp(arg, "--strict")) {
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strict = 1;
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continue;
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}
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if (starts_with(arg, "--pack_header=")) {
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struct pack_header *hdr;
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char *c;
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hdr = (struct pack_header *)buffer;
|
|
hdr->hdr_signature = htonl(PACK_SIGNATURE);
|
|
hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
|
|
if (*c != ',')
|
|
die("bad %s", arg);
|
|
hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
|
|
if (*c)
|
|
die("bad %s", arg);
|
|
len = sizeof(*hdr);
|
|
continue;
|
|
}
|
|
usage(unpack_usage);
|
|
}
|
|
|
|
/* We don't take any non-flag arguments now.. Maybe some day */
|
|
usage(unpack_usage);
|
|
}
|
|
git_SHA1_Init(&ctx);
|
|
unpack_all();
|
|
git_SHA1_Update(&ctx, buffer, offset);
|
|
git_SHA1_Final(sha1, &ctx);
|
|
if (strict)
|
|
write_rest();
|
|
if (hashcmp(fill(20), sha1))
|
|
die("final sha1 did not match");
|
|
use(20);
|
|
|
|
/* Write the last part of the buffer to stdout */
|
|
while (len) {
|
|
int ret = xwrite(1, buffer + offset, len);
|
|
if (ret <= 0)
|
|
break;
|
|
len -= ret;
|
|
offset += ret;
|
|
}
|
|
|
|
/* All done */
|
|
return has_errors;
|
|
}
|