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[PATCH v2 6/8] upload-pack: refactor reading of pack-objects out

From
JTJonathan Tan <jonathantanmy@google.com>
Date
Mar 8, 2019, 21:55 UTC
Message-ID
<d487f46b0fe3ba32928b26c38af180edf1fa4f23.1552073690.git.jonathantanmy@google.com>
In-Reply-To
<cover.1552073690.git.jonathantanmy@google.com>

Subsequent patches will change how the output of pack-objects is processed, so extract that processing into its own function.

Currently, at most 1 character can be buffered (in the "buffered" local variable). One of those patches will require a larger buffer, so replace that "buffered" local variable with a buffer array.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 upload-pack.c | 81 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 47 insertions(+), 34 deletions(-)
diff --git a/upload-pack.c b/upload-pack.c
index d098ef5982..987d2e139b 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -102,14 +102,52 @@ static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 	return 0;
 }
 
+struct output_state {
+	char buffer[8193];
+	int used;
+};
+
+static int relay_pack_data(int pack_objects_out, struct output_state *os)
+{
+	/*
+	 * We keep the last byte to ourselves
+	 * in case we detect broken rev-list, so that we
+	 * can leave the stream corrupted.  This is
+	 * unfortunate -- unpack-objects would happily
+	 * accept a valid packdata with trailing garbage,
+	 * so appending garbage after we pass all the
+	 * pack data is not good enough to signal
+	 * breakage to downstream.
+	 */
+	ssize_t readsz;
+
+	readsz = xread(pack_objects_out, os->buffer + os->used,
+		       sizeof(os->buffer) - os->used);
+	if (readsz < 0) {
+		return readsz;
+	}
+	os->used += readsz;
+
+	if (os->used > 1) {
+		send_client_data(1, os->buffer, os->used - 1);
+		os->buffer[0] = os->buffer[os->used - 1];
+		os->used = 1;
+	} else {
+		send_client_data(1, os->buffer, os->used);
+		os->used = 0;
+	}
+
+	return readsz;
+}
+
 static void create_pack_file(const struct object_array *have_obj,
 			     const struct object_array *want_obj)
 {
 	struct child_process pack_objects = CHILD_PROCESS_INIT;
-	char data[8193], progress[128];
+	struct output_state output_state = {0};
+	char progress[128];
 	char abort_msg[] = "aborting due to possible repository "
 		"corruption on the remote side.";
-	int buffered = -1;
 	ssize_t sz;
 	int i;
 	FILE *pipe_fd;
@@ -239,39 +277,15 @@ static void create_pack_file(const struct object_array *have_obj,
 			continue;
 		}
 		if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
-			/* Data ready; we keep the last byte to ourselves
-			 * in case we detect broken rev-list, so that we
-			 * can leave the stream corrupted.  This is
-			 * unfortunate -- unpack-objects would happily
-			 * accept a valid packdata with trailing garbage,
-			 * so appending garbage after we pass all the
-			 * pack data is not good enough to signal
-			 * breakage to downstream.
-			 */
-			char *cp = data;
-			ssize_t outsz = 0;
-			if (0 <= buffered) {
-				*cp++ = buffered;
-				outsz++;
-			}
-			sz = xread(pack_objects.out, cp,
-				  sizeof(data) - outsz);
-			if (0 < sz)
-				;
-			else if (sz == 0) {
+			int result = relay_pack_data(pack_objects.out,
+						     &output_state);
+
+			if (result == 0) {
 				close(pack_objects.out);
 				pack_objects.out = -1;
-			}
-			else
+			} else if (result < 0) {
 				goto fail;
-			sz += outsz;
-			if (1 < sz) {
-				buffered = data[sz-1] & 0xFF;
-				sz--;
 			}
-			else
-				buffered = -1;
-			send_client_data(1, data, sz);
 		}
 
 		/*
@@ -296,9 +310,8 @@ static void create_pack_file(const struct object_array *have_obj,
 	}
 
 	/* flush the data */
-	if (0 <= buffered) {
-		data[0] = buffered;
-		send_client_data(1, data, 1);
+	if (output_state.used > 0) {
+		send_client_data(1, output_state.buffer, output_state.used);
 		fprintf(stderr, "flushed.\n");
 	}
 	if (use_sideband)
-- 
2.19.0.271.gfe8321ec05.dirty
Previous: Junio C HamanoNext: Jonathan Tan
Message 39 of 45 in “[WIP 0/7] CDN offloading of fetch response”
  1. Jonathan TanFeb 23, 2019
  2. 1/7 http: use --stdin and --keep when downloading packJonathan Tan, Feb 23, 2019
  3. 2/7 http: improve documentation of http_pack_requestJonathan Tan, Feb 23, 2019
  4. 3/7 http-fetch: support fetching packfiles by URLJonathan Tan, Feb 23, 2019
  5. 4/7 Documentation: order protocol v2 sectionsJonathan Tan, Feb 23, 2019
  6. 5/7 Documentation: add Packfile URIs design docJonathan Tan, Feb 23, 2019
  7. 6/7 upload-pack: refactor reading of pack-objects outJonathan Tan, Feb 23, 2019
  8. 7/7 upload-pack: send part of packfile response as uriJonathan Tan, Feb 23, 2019
  9. Junio C HamanoFeb 24, 2019
  10. Christian CouderFeb 25, 2019
  11. Jonathan NiederFeb 26, 2019
  12. Christian CouderFeb 26, 2019
  13. Josh SteadmonMar 1, 2019
  14. Jonathan TanMar 1, 2019
  15. Christian CouderFeb 25, 2019
  16. Jonathan NiederFeb 25, 2019
  17. Christian CouderFeb 26, 2019
  18. Ævar Arnfjörð BjarmasonFeb 26, 2019
  19. Christian CouderMar 4, 2019
  20. Jonathan NiederFeb 28, 2019
  21. Christian CouderMar 4, 2019
  22. 0/8 CDN offloading of fetch responseJonathan Tan, Mar 8, 2019
  23. 1/8 http: use --stdin when getting dumb HTTP packJonathan Tan, Mar 8, 2019
  24. 2/8 http: improve documentation of http_pack_requestJonathan Tan, Mar 8, 2019
  25. 3/8 http-fetch: support fetching packfiles by URLJonathan Tan, Mar 8, 2019
  26. 4/8 Documentation: order protocol v2 sectionsJonathan Tan, Mar 8, 2019
  27. 5/8 Documentation: add Packfile URIs design docJonathan Tan, Mar 8, 2019
  28. Jeff KingApr 23, 2019
  29. Jonathan TanApr 23, 2019
  30. Ævar Arnfjörð BjarmasonApr 23, 2019
  31. Jonathan NiederApr 23, 2019
  32. Ævar Arnfjörð BjarmasonApr 23, 2019
  33. Jonathan NiederApr 23, 2019
  34. Jonathan NiederApr 23, 2019
  35. Ævar Arnfjörð BjarmasonApr 23, 2019
  36. Jonathan NiederApr 23, 2019
  37. Ævar Arnfjörð BjarmasonApr 24, 2019
  38. Junio C HamanoApr 24, 2019
  39. 6/8 upload-pack: refactor reading of pack-objects outJonathan Tan, Mar 8, 2019
  40. 7/8 fetch-pack: support more than one pack lockfileJonathan Tan, Mar 8, 2019
  41. 8/8 upload-pack: send part of packfile response as uriJonathan Tan, Mar 8, 2019
  42. Josh SteadmonMar 19, 2019
  43. Jeff KingApr 23, 2019
  44. Jonathan TanApr 23, 2019
  45. Ævar Arnfjörð BjarmasonApr 24, 2019

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