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/*
* Copyright (c) 2011, Google Inc.
*/
#include "cache.h"
#include "streaming.h"
enum input_source {
stream_error = -1,
incore = 0,
loose = 1,
pack_non_delta = 2
};
typedef int (*open_istream_fn)(struct git_istream *,
struct object_info *,
const unsigned char *,
enum object_type *);
typedef int (*close_istream_fn)(struct git_istream *);
typedef ssize_t (*read_istream_fn)(struct git_istream *, char *, size_t);
struct stream_vtbl {
close_istream_fn close;
read_istream_fn read;
};
#define open_method_decl(name) \
int open_istream_ ##name \
(struct git_istream *st, struct object_info *oi, \
const unsigned char *sha1, \
enum object_type *type)
#define close_method_decl(name) \
int close_istream_ ##name \
(struct git_istream *st)
#define read_method_decl(name) \
ssize_t read_istream_ ##name \
(struct git_istream *st, char *buf, size_t sz)
/* forward declaration */
static open_method_decl(incore);
static open_method_decl(loose);
static open_method_decl(pack_non_delta);
static open_istream_fn open_istream_tbl[] = {
open_istream_incore,
open_istream_loose,
open_istream_pack_non_delta,
};
struct git_istream {
const struct stream_vtbl *vtbl;
unsigned long size; /* inflated size of full object */
union {
struct {
char *buf; /* from read_object() */
unsigned long read_ptr;
} incore;
struct {
int fd; /* open for reading */
/* NEEDSWORK: what else? */
} loose;
struct {
int fd; /* open for reading */
/* NEEDSWORK: what else? */
} in_pack;
} u;
};
int close_istream(struct git_istream *st)
{
return st->vtbl->close(st);
}
ssize_t read_istream(struct git_istream *st, char *buf, size_t sz)
{
return st->vtbl->read(st, buf, sz);
}
static enum input_source istream_source(const unsigned char *sha1,
enum object_type *type,
struct object_info *oi)
{
unsigned long size;
int status;
oi->sizep = &size;
status = sha1_object_info_extended(sha1, oi);
if (status < 0)
return stream_error;
*type = status;
switch (oi->whence) {
case OI_LOOSE:
return loose;
case OI_PACKED:
if (!oi->u.packed.is_delta && big_file_threshold <= size)
return pack_non_delta;
/* fallthru */
default:
return incore;
}
}
struct git_istream *open_istream(const unsigned char *sha1,
enum object_type *type,
unsigned long *size)
{
struct git_istream *st;
struct object_info oi;
const unsigned char *real = lookup_replace_object(sha1);
enum input_source src = istream_source(real, type, &oi);
if (src < 0)
return NULL;
st = xmalloc(sizeof(*st));
if (open_istream_tbl[src](st, &oi, real, type)) {
if (open_istream_incore(st, &oi, real, type)) {
free(st);
return NULL;
}
}
*size = st->size;
return st;
}
/*****************************************************************
*
* Loose object stream
*
*****************************************************************/
static open_method_decl(loose)
{
return -1; /* for now */
}
/*****************************************************************
*
* Non-delta packed object stream
*
*****************************************************************/
static open_method_decl(pack_non_delta)
{
return -1; /* for now */
}
/*****************************************************************
*
* In-core stream
*
*****************************************************************/
static close_method_decl(incore)
{
free(st->u.incore.buf);
return 0;
}
static read_method_decl(incore)
{
size_t read_size = sz;
size_t remainder = st->size - st->u.incore.read_ptr;
if (remainder <= read_size)
read_size = remainder;
if (read_size) {
memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
st->u.incore.read_ptr += read_size;
}
return read_size;
}
static struct stream_vtbl incore_vtbl = {
close_istream_incore,
read_istream_incore,
};
static open_method_decl(incore)
{
st->u.incore.buf = read_sha1_file_extended(sha1, type, &st->size, 0);
st->u.incore.read_ptr = 0;
st->vtbl = &incore_vtbl;
return st->u.incore.buf ? 0 : -1;
}
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