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authorJunio C Hamano <gitster@pobox.com>2011-05-20 21:33:31 (GMT)
committerJunio C Hamano <gitster@pobox.com>2011-05-26 23:47:15 (GMT)
commitb6691092d707860019bbab80eaaf9173ada10586 (patch)
treeb9e7e80502085bb9237a4d1726afb38a36fb5ba8 /streaming.c
parentd1bf0e08313927c269846476f99f59d878807371 (diff)
downloadgit-b6691092d707860019bbab80eaaf9173ada10586.zip
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Add streaming filter API
This introduces an API to plug custom filters to an input stream. The caller gets get_stream_filter("path") to obtain an appropriate filter for the path, and then uses it when opening an input stream via open_istream(). After that, the caller can read from the stream with read_istream(), and close it with close_istream(), just like an unfiltered stream. This only adds a "null" filter that is a pass-thru filter, but later changes can add LF-to-CRLF and other filters, and the callers of the streaming API do not have to change. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'streaming.c')
-rw-r--r--streaming.c100
1 files changed, 99 insertions, 1 deletions
diff --git a/streaming.c b/streaming.c
index 0602926..565f000 100644
--- a/streaming.c
+++ b/streaming.c
@@ -41,6 +41,9 @@ struct stream_vtbl {
static open_method_decl(incore);
static open_method_decl(loose);
static open_method_decl(pack_non_delta);
+static struct git_istream *attach_stream_filter(struct git_istream *st,
+ struct stream_filter *filter);
+
static open_istream_fn open_istream_tbl[] = {
open_istream_incore,
@@ -48,6 +51,17 @@ static open_istream_fn open_istream_tbl[] = {
open_istream_pack_non_delta,
};
+#define FILTER_BUFFER (1024*16)
+
+struct filtered_istream {
+ struct git_istream *upstream;
+ struct stream_filter *filter;
+ char ibuf[FILTER_BUFFER];
+ char obuf[FILTER_BUFFER];
+ int i_end, i_ptr;
+ int o_end, o_ptr;
+};
+
struct git_istream {
const struct stream_vtbl *vtbl;
unsigned long size; /* inflated size of full object */
@@ -72,6 +86,8 @@ struct git_istream {
struct packed_git *pack;
off_t pos;
} in_pack;
+
+ struct filtered_istream filtered;
} u;
};
@@ -112,7 +128,8 @@ static enum input_source istream_source(const unsigned char *sha1,
struct git_istream *open_istream(const unsigned char *sha1,
enum object_type *type,
- unsigned long *size)
+ unsigned long *size,
+ struct stream_filter *filter)
{
struct git_istream *st;
struct object_info oi;
@@ -129,6 +146,14 @@ struct git_istream *open_istream(const unsigned char *sha1,
return NULL;
}
}
+ if (st && filter) {
+ /* Add "&& !is_null_stream_filter(filter)" for performance */
+ struct git_istream *nst = attach_stream_filter(st, filter);
+ if (!nst)
+ close_istream(st);
+ st = nst;
+ }
+
*size = st->size;
return st;
}
@@ -149,6 +174,79 @@ static void close_deflated_stream(struct git_istream *st)
/*****************************************************************
*
+ * Filtered stream
+ *
+ *****************************************************************/
+
+static close_method_decl(filtered)
+{
+ free_stream_filter(st->u.filtered.filter);
+ return close_istream(st->u.filtered.upstream);
+}
+
+static read_method_decl(filtered)
+{
+ struct filtered_istream *fs = &(st->u.filtered);
+ size_t filled = 0;
+
+ while (sz) {
+ /* do we already have filtered output? */
+ if (fs->o_ptr < fs->o_end) {
+ size_t to_move = fs->o_end - fs->o_ptr;
+ if (sz < to_move)
+ to_move = sz;
+ memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
+ fs->o_ptr += to_move;
+ sz -= to_move;
+ filled += to_move;
+ continue;
+ }
+ fs->o_end = fs->o_ptr = 0;
+
+ /* do we have anything to feed the filter with? */
+ if (fs->i_ptr < fs->i_end) {
+ size_t to_feed = fs->i_end - fs->i_ptr;
+ size_t to_receive = FILTER_BUFFER;
+ if (stream_filter(fs->filter,
+ fs->ibuf + fs->i_ptr, &to_feed,
+ fs->obuf, &to_receive))
+ return -1;
+ fs->i_ptr = fs->i_end - to_feed;
+ fs->o_end = FILTER_BUFFER - to_receive;
+ continue;
+ }
+ fs->i_end = fs->i_ptr = 0;
+
+ /* refill the input from the upstream */
+ fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
+ if (fs->i_end <= 0)
+ break;
+ }
+ return filled;
+}
+
+static struct stream_vtbl filtered_vtbl = {
+ close_istream_filtered,
+ read_istream_filtered,
+};
+
+static struct git_istream *attach_stream_filter(struct git_istream *st,
+ struct stream_filter *filter)
+{
+ struct git_istream *ifs = xmalloc(sizeof(*ifs));
+ struct filtered_istream *fs = &(ifs->u.filtered);
+
+ ifs->vtbl = &filtered_vtbl;
+ fs->upstream = st;
+ fs->filter = filter;
+ fs->i_end = fs->i_ptr = 0;
+ fs->o_end = fs->o_ptr = 0;
+ ifs->size = -1; /* unknown */
+ return ifs;
+}
+
+/*****************************************************************
+ *
* Loose object stream
*
*****************************************************************/