diff options
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | streaming.c | 193 | ||||
| -rw-r--r-- | streaming.h | 15 |
3 files changed, 210 insertions, 0 deletions
@@ -552,6 +552,7 @@ LIB_H += sha1-lookup.h LIB_H += sideband.h LIB_H += sigchain.h LIB_H += strbuf.h +LIB_H += streaming.h LIB_H += string-list.h LIB_H += submodule.h LIB_H += tag.h @@ -657,6 +658,7 @@ LIB_OBJS += shallow.o LIB_OBJS += sideband.o LIB_OBJS += sigchain.o LIB_OBJS += strbuf.o +LIB_OBJS += streaming.o LIB_OBJS += string-list.o LIB_OBJS += submodule.o LIB_OBJS += symlinks.o diff --git a/streaming.c b/streaming.c new file mode 100644 index 0000000000..13cbce7aab --- /dev/null +++ b/streaming.c @@ -0,0 +1,193 @@ +/* + * 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; +} diff --git a/streaming.h b/streaming.h new file mode 100644 index 0000000000..18cbe68ac1 --- /dev/null +++ b/streaming.h @@ -0,0 +1,15 @@ +/* + * Copyright (c) 2011, Google Inc. + */ +#ifndef STREAMING_H +#define STREAMING_H 1 +#include "cache.h" + +/* opaque */ +struct git_istream; + +extern struct git_istream *open_istream(const unsigned char *, enum object_type *, unsigned long *); +extern int close_istream(struct git_istream *); +extern ssize_t read_istream(struct git_istream *, char *, size_t); + +#endif /* STREAMING_H */ |