Hash :
5e0de328
Author :
Date :
2012-02-13T17:10:24
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/*
* Copyright (C) 2009-2012 the libgit2 contributors
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#include "common.h"
#include "git2/zlib.h"
#include "git2/object.h"
#include "fileops.h"
#include "hash.h"
#include "odb.h"
#include "delta-apply.h"
#include "git2/odb_backend.h"
#define GIT_ALTERNATES_FILE "info/alternates"
/* TODO: is this correct? */
#define GIT_LOOSE_PRIORITY 2
#define GIT_PACKED_PRIORITY 1
typedef struct
{
git_odb_backend *backend;
int priority;
int is_alternate;
} backend_internal;
static int format_object_header(char *hdr, size_t n, size_t obj_len, git_otype obj_type)
{
const char *type_str = git_object_type2string(obj_type);
int len = p_snprintf(hdr, n, "%s %"PRIuZ, type_str, obj_len);
if (len < 0 || len >= (int)n)
return git__throw(GIT_ERROR, "Cannot format object header. Length is out of bounds");
return len+1;
}
int git_odb__hashobj(git_oid *id, git_rawobj *obj)
{
git_buf_vec vec[2];
char header[64];
int hdrlen;
assert(id && obj);
if (!git_object_typeisloose(obj->type))
return git__throw(GIT_ERROR, "Failed to hash object. Wrong object type");
if (!obj->data && obj->len != 0)
return git__throw(GIT_ERROR, "Failed to hash object. No data given");
if ((hdrlen = format_object_header(header, sizeof(header), obj->len, obj->type)) < 0)
return git__rethrow(hdrlen, "Failed to hash object");
vec[0].data = header;
vec[0].len = hdrlen;
vec[1].data = obj->data;
vec[1].len = obj->len;
git_hash_vec(id, vec, 2);
return GIT_SUCCESS;
}
static git_odb_object *new_odb_object(const git_oid *oid, git_rawobj *source)
{
git_odb_object *object = git__malloc(sizeof(git_odb_object));
memset(object, 0x0, sizeof(git_odb_object));
git_oid_cpy(&object->cached.oid, oid);
memcpy(&object->raw, source, sizeof(git_rawobj));
return object;
}
static void free_odb_object(void *o)
{
git_odb_object *object = (git_odb_object *)o;
if (object != NULL) {
git__free(object->raw.data);
git__free(object);
}
}
const git_oid *git_odb_object_id(git_odb_object *object)
{
return &object->cached.oid;
}
const void *git_odb_object_data(git_odb_object *object)
{
return object->raw.data;
}
size_t git_odb_object_size(git_odb_object *object)
{
return object->raw.len;
}
git_otype git_odb_object_type(git_odb_object *object)
{
return object->raw.type;
}
void git_odb_object_free(git_odb_object *object)
{
git_cached_obj_decref((git_cached_obj *)object, &free_odb_object);
}
int git_odb__hashfd(git_oid *out, git_file fd, size_t size, git_otype type)
{
int hdr_len;
char hdr[64], buffer[2048];
git_hash_ctx *ctx;
hdr_len = format_object_header(hdr, sizeof(hdr), size, type);
if (hdr_len < 0)
return git__throw(GIT_ERROR, "Failed to format blob header. Length is out of bounds");
ctx = git_hash_new_ctx();
git_hash_update(ctx, hdr, hdr_len);
while (size > 0) {
ssize_t read_len = read(fd, buffer, sizeof(buffer));
if (read_len < 0) {
git_hash_free_ctx(ctx);
return git__throw(GIT_EOSERR, "Error when reading file: %s", strerror(errno));
}
git_hash_update(ctx, buffer, read_len);
size -= read_len;
}
git_hash_final(out, ctx);
git_hash_free_ctx(ctx);
return GIT_SUCCESS;
}
int git_odb__hashlink(git_oid *out, const char *path)
{
struct stat st;
int error;
git_off_t size;
error = p_lstat(path, &st);
if (error < 0)
return git__throw(GIT_EOSERR, "Failed to stat blob. %s", strerror(errno));
size = st.st_size;
if (!git__is_sizet(size))
return git__throw(GIT_EOSERR, "File size overflow for 32-bit systems");
if (S_ISLNK(st.st_mode)) {
char *link_data;
ssize_t read_len;
link_data = git__malloc(size);
if (link_data == NULL)
return GIT_ENOMEM;
read_len = p_readlink(path, link_data, size + 1);
if (read_len != (ssize_t)size)
return git__throw(GIT_EOSERR, "Failed to read symlink data");
error = git_odb_hash(out, link_data, (size_t)size, GIT_OBJ_BLOB);
free(link_data);
} else {
int fd;
if ((fd = p_open(path, O_RDONLY)) < 0)
return git__throw(GIT_ENOTFOUND, "Could not open '%s'", path);
error = git_odb__hashfd(out, fd, (size_t)size, GIT_OBJ_BLOB);
p_close(fd);
}
return error;
}
int git_odb_hashfile(git_oid *out, const char *path, git_otype type)
{
int fd, error;
git_off_t size;
if ((fd = p_open(path, O_RDONLY)) < 0)
return git__throw(GIT_ENOTFOUND, "Could not open '%s'", path);
if ((size = git_futils_filesize(fd)) < 0 || !git__is_sizet(size)) {
p_close(fd);
return git__throw(GIT_EOSERR,
"File size overflow. The object is too big to fit in 32-bit mode");
}
error = git_odb__hashfd(out, fd, (size_t)size, type);
p_close(fd);
return error;
}
int git_odb_hash(git_oid *id, const void *data, size_t len, git_otype type)
{
git_rawobj raw;
assert(id);
raw.data = (void *)data;
raw.len = len;
raw.type = type;
return git_odb__hashobj(id, &raw);
}
/**
* FAKE WSTREAM
*/
typedef struct {
git_odb_stream stream;
char *buffer;
size_t size, written;
git_otype type;
} fake_wstream;
static int fake_wstream__fwrite(git_oid *oid, git_odb_stream *_stream)
{
fake_wstream *stream = (fake_wstream *)_stream;
return _stream->backend->write(oid, _stream->backend, stream->buffer, stream->size, stream->type);
}
static int fake_wstream__write(git_odb_stream *_stream, const char *data, size_t len)
{
fake_wstream *stream = (fake_wstream *)_stream;
if (stream->written + len > stream->size)
return GIT_ENOMEM;
memcpy(stream->buffer + stream->written, data, len);
stream->written += len;
return GIT_SUCCESS;
}
static void fake_wstream__free(git_odb_stream *_stream)
{
fake_wstream *stream = (fake_wstream *)_stream;
git__free(stream->buffer);
git__free(stream);
}
static int init_fake_wstream(git_odb_stream **stream_p, git_odb_backend *backend, size_t size, git_otype type)
{
fake_wstream *stream;
stream = git__calloc(1, sizeof(fake_wstream));
if (stream == NULL)
return GIT_ENOMEM;
stream->size = size;
stream->type = type;
stream->buffer = git__malloc(size);
if (stream->buffer == NULL) {
git__free(stream);
return GIT_ENOMEM;
}
stream->stream.backend = backend;
stream->stream.read = NULL; /* read only */
stream->stream.write = &fake_wstream__write;
stream->stream.finalize_write = &fake_wstream__fwrite;
stream->stream.free = &fake_wstream__free;
stream->stream.mode = GIT_STREAM_WRONLY;
*stream_p = (git_odb_stream *)stream;
return GIT_SUCCESS;
}
/***********************************************************
*
* OBJECT DATABASE PUBLIC API
*
* Public calls for the ODB functionality
*
***********************************************************/
static int backend_sort_cmp(const void *a, const void *b)
{
const backend_internal *backend_a = (const backend_internal *)(a);
const backend_internal *backend_b = (const backend_internal *)(b);
if (backend_a->is_alternate == backend_b->is_alternate)
return (backend_b->priority - backend_a->priority);
return backend_a->is_alternate ? 1 : -1;
}
int git_odb_new(git_odb **out)
{
int error;
git_odb *db = git__calloc(1, sizeof(*db));
if (!db)
return GIT_ENOMEM;
error = git_cache_init(&db->cache, GIT_DEFAULT_CACHE_SIZE, &free_odb_object);
if (error < GIT_SUCCESS) {
git__free(db);
return git__rethrow(error, "Failed to create object database");
}
if ((error = git_vector_init(&db->backends, 4, backend_sort_cmp)) < GIT_SUCCESS) {
git__free(db);
return git__rethrow(error, "Failed to create object database");
}
*out = db;
GIT_REFCOUNT_INC(db);
return GIT_SUCCESS;
}
static int add_backend_internal(git_odb *odb, git_odb_backend *backend, int priority, int is_alternate)
{
backend_internal *internal;
assert(odb && backend);
if (backend->odb != NULL && backend->odb != odb)
return git__throw(GIT_EBUSY, "The backend is already owned by another ODB");
internal = git__malloc(sizeof(backend_internal));
if (internal == NULL)
return GIT_ENOMEM;
internal->backend = backend;
internal->priority = priority;
internal->is_alternate = is_alternate;
if (git_vector_insert(&odb->backends, internal) < 0) {
git__free(internal);
return GIT_ENOMEM;
}
git_vector_sort(&odb->backends);
internal->backend->odb = odb;
return GIT_SUCCESS;
}
int git_odb_add_backend(git_odb *odb, git_odb_backend *backend, int priority)
{
return add_backend_internal(odb, backend, priority, 0);
}
int git_odb_add_alternate(git_odb *odb, git_odb_backend *backend, int priority)
{
return add_backend_internal(odb, backend, priority, 1);
}
static int add_default_backends(git_odb *db, const char *objects_dir, int as_alternates)
{
git_odb_backend *loose, *packed;
int error;
/* add the loose object backend */
error = git_odb_backend_loose(&loose, objects_dir, -1, 0);
if (error < GIT_SUCCESS)
return error;
error = add_backend_internal(db, loose, GIT_LOOSE_PRIORITY, as_alternates);
if (error < GIT_SUCCESS)
return git__rethrow(error, "Failed to add backend");
/* add the packed file backend */
error = git_odb_backend_pack(&packed, objects_dir);
if (error < GIT_SUCCESS)
return error;
error = add_backend_internal(db, packed, GIT_PACKED_PRIORITY, as_alternates);
if (error < GIT_SUCCESS)
return git__rethrow(error, "Failed to add backend");
return GIT_SUCCESS;
}
static int load_alternates(git_odb *odb, const char *objects_dir)
{
git_buf alternates_path = GIT_BUF_INIT;
char *buffer;
git_fbuffer alternates_buf = GIT_FBUFFER_INIT;
const char *alternate;
int error;
error = git_buf_joinpath(&alternates_path, objects_dir, GIT_ALTERNATES_FILE);
if (error < GIT_SUCCESS)
return error;
if (git_path_exists(alternates_path.ptr) < GIT_SUCCESS) {
git_buf_free(&alternates_path);
return GIT_SUCCESS;
}
if (git_futils_readbuffer(&alternates_buf, alternates_path.ptr) < GIT_SUCCESS) {
git_buf_free(&alternates_path);
return git__throw(GIT_EOSERR, "Failed to add backend. Can't read alternates");
}
buffer = (char *)alternates_buf.data;
error = GIT_SUCCESS;
/* add each alternate as a new backend; one alternate per line */
while ((alternate = git__strtok(&buffer, "\r\n")) != NULL) {
if (*alternate == '\0' || *alternate == '#')
continue;
/* relative path: build based on the current `objects` folder */
if (*alternate == '.') {
error = git_buf_joinpath(&alternates_path, objects_dir, alternate);
if (error < GIT_SUCCESS)
break;
alternate = git_buf_cstr(&alternates_path);
}
if ((error = add_default_backends(odb, alternate, 1)) < GIT_SUCCESS)
break;
}
git_buf_free(&alternates_path);
git_futils_freebuffer(&alternates_buf);
if (error < GIT_SUCCESS)
return git__rethrow(error, "Failed to load alternates");
return error;
}
int git_odb_open(git_odb **out, const char *objects_dir)
{
git_odb *db;
int error;
assert(out && objects_dir);
*out = NULL;
if ((error = git_odb_new(&db)) < 0)
return git__rethrow(error, "Failed to open ODB");
if ((error = add_default_backends(db, objects_dir, 0)) < GIT_SUCCESS)
goto cleanup;
if ((error = load_alternates(db, objects_dir)) < GIT_SUCCESS)
goto cleanup;
*out = db;
return GIT_SUCCESS;
cleanup:
git_odb_free(db);
return error; /* error already set - pass through */
}
static void odb_free(git_odb *db)
{
unsigned int i;
for (i = 0; i < db->backends.length; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *backend = internal->backend;
if (backend->free) backend->free(backend);
else git__free(backend);
git__free(internal);
}
git_vector_free(&db->backends);
git_cache_free(&db->cache);
git__free(db);
}
void git_odb_free(git_odb *db)
{
if (db == NULL)
return;
GIT_REFCOUNT_DEC(db, odb_free);
}
int git_odb_exists(git_odb *db, const git_oid *id)
{
git_odb_object *object;
unsigned int i;
int found = 0;
assert(db && id);
if ((object = git_cache_get(&db->cache, id)) != NULL) {
git_odb_object_free(object);
return 1;
}
for (i = 0; i < db->backends.length && !found; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *b = internal->backend;
if (b->exists != NULL)
found = b->exists(b, id);
}
return found;
}
int git_odb_read_header(size_t *len_p, git_otype *type_p, git_odb *db, const git_oid *id)
{
unsigned int i;
int error = GIT_ENOTFOUND;
git_odb_object *object;
assert(db && id);
if ((object = git_cache_get(&db->cache, id)) != NULL) {
*len_p = object->raw.len;
*type_p = object->raw.type;
git_odb_object_free(object);
return GIT_SUCCESS;
}
for (i = 0; i < db->backends.length && error < 0; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *b = internal->backend;
if (b->read_header != NULL)
error = b->read_header(len_p, type_p, b, id);
}
if (error == GIT_EPASSTHROUGH)
return GIT_SUCCESS;
/*
* no backend could read only the header.
* try reading the whole object and freeing the contents
*/
if (error < 0) {
if ((error = git_odb_read(&object, db, id)) < GIT_SUCCESS)
return error; /* error already set - pass through */
*len_p = object->raw.len;
*type_p = object->raw.type;
git_odb_object_free(object);
}
return GIT_SUCCESS;
}
int git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id)
{
unsigned int i;
int error = GIT_ENOTFOUND;
git_rawobj raw;
assert(out && db && id);
*out = git_cache_get(&db->cache, id);
if (*out != NULL)
return GIT_SUCCESS;
for (i = 0; i < db->backends.length && error < 0; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *b = internal->backend;
if (b->read != NULL)
error = b->read(&raw.data, &raw.len, &raw.type, b, id);
}
if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS) {
*out = git_cache_try_store(&db->cache, new_odb_object(id, &raw));
return GIT_SUCCESS;
}
return git__rethrow(error, "Failed to read object");
}
int git_odb_read_prefix(git_odb_object **out, git_odb *db, const git_oid *short_id, unsigned int len)
{
unsigned int i;
int error = GIT_ENOTFOUND;
git_oid full_oid;
git_rawobj raw;
int found = 0;
assert(out && db);
if (len < GIT_OID_MINPREFIXLEN)
return git__throw(GIT_EAMBIGUOUSOIDPREFIX, "Failed to lookup object. Prefix length is lower than %d.", GIT_OID_MINPREFIXLEN);
if (len > GIT_OID_HEXSZ)
len = GIT_OID_HEXSZ;
if (len == GIT_OID_HEXSZ) {
*out = git_cache_get(&db->cache, short_id);
if (*out != NULL)
return GIT_SUCCESS;
}
for (i = 0; i < db->backends.length && found < 2; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *b = internal->backend;
if (b->read != NULL) {
error = b->read_prefix(&full_oid, &raw.data, &raw.len, &raw.type, b, short_id, len);
switch (error) {
case GIT_SUCCESS:
found++;
break;
case GIT_ENOTFOUND:
case GIT_EPASSTHROUGH:
break;
case GIT_EAMBIGUOUSOIDPREFIX:
return git__rethrow(error, "Failed to read object. Ambiguous sha1 prefix");
default:
return git__rethrow(error, "Failed to read object");
}
}
}
if (found == 1) {
*out = git_cache_try_store(&db->cache, new_odb_object(&full_oid, &raw));
} else if (found > 1) {
return git__throw(GIT_EAMBIGUOUSOIDPREFIX, "Failed to read object. Ambiguous sha1 prefix");
} else {
return git__throw(GIT_ENOTFOUND, "Failed to read object. Object not found");
}
return GIT_SUCCESS;
}
int git_odb_write(git_oid *oid, git_odb *db, const void *data, size_t len, git_otype type)
{
unsigned int i;
int error = GIT_ERROR;
git_odb_stream *stream;
assert(oid && db);
for (i = 0; i < db->backends.length && error < 0; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *b = internal->backend;
/* we don't write in alternates! */
if (internal->is_alternate)
continue;
if (b->write != NULL)
error = b->write(oid, b, data, len, type);
}
if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS)
return GIT_SUCCESS;
/* if no backends were able to write the object directly, we try a streaming
* write to the backends; just write the whole object into the stream in one
* push */
if ((error = git_odb_open_wstream(&stream, db, len, type)) == GIT_SUCCESS) {
stream->write(stream, data, len);
error = stream->finalize_write(oid, stream);
stream->free(stream);
return GIT_SUCCESS;
}
return git__rethrow(error, "Failed to write object");
}
int git_odb_open_wstream(git_odb_stream **stream, git_odb *db, size_t size, git_otype type)
{
unsigned int i;
int error = GIT_ERROR;
assert(stream && db);
for (i = 0; i < db->backends.length && error < 0; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *b = internal->backend;
/* we don't write in alternates! */
if (internal->is_alternate)
continue;
if (b->writestream != NULL)
error = b->writestream(stream, b, size, type);
else if (b->write != NULL)
error = init_fake_wstream(stream, b, size, type);
}
if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS)
return GIT_SUCCESS;
return git__rethrow(error, "Failed to open write stream");
}
int git_odb_open_rstream(git_odb_stream **stream, git_odb *db, const git_oid *oid)
{
unsigned int i;
int error = GIT_ERROR;
assert(stream && db);
for (i = 0; i < db->backends.length && error < 0; ++i) {
backend_internal *internal = git_vector_get(&db->backends, i);
git_odb_backend *b = internal->backend;
if (b->readstream != NULL)
error = b->readstream(stream, b, oid);
}
if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS)
return GIT_SUCCESS;
return git__rethrow(error, "Failed to open read stream");
}