git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH 5/8] vcs-svn: Read delta preimage from file descriptor

From
Jonathan Nieder <jrnieder@gmail.com>
Date
Nov 20, 2010, 19:27 UTC
Message-ID
<20101120192713.GF17823@burratino>
In-Reply-To
<20101120192153.GA17823@burratino>

Teach the svndiff routines to read the preimage for a delta from a file descriptor without reading ahead. This way, the delta applier can stream its input directly from fast-import's cat-blob-fd pipe.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 test-svn-fe.c            |   10 +++++-----
 vcs-svn/sliding_window.c |   21 +++++++++------------
 vcs-svn/sliding_window.h |    2 +-
 vcs-svn/svndiff.c        |    6 +++---
 vcs-svn/svndiff.h        |    2 +-
 5 files changed, 19 insertions(+), 22 deletions(-)
diff --git a/test-svn-fe.c b/test-svn-fe.c
index 4799e4c..4ea0cd6 100644
--- a/test-svn-fe.c
+++ b/test-svn-fe.c
@@ -22,20 +22,20 @@ int main(int argc, char *argv[])
 		return 0;
 	}
 	if (argc == 5 && !strcmp(argv[1], "-d")) {
-		struct line_buffer preimage = LINE_BUFFER_INIT;
+		int preimage_fd = -1;
 		struct line_buffer delta = LINE_BUFFER_INIT;
-		if (buffer_init(&preimage, argv[2]))
+		preimage_fd = open(argv[2], O_RDONLY);
+		if (preimage_fd < 0)
 			die_errno("cannot open preimage");
 		if (buffer_init(&delta, argv[3]))
 			die_errno("cannot open delta");
 		if (svndiff0_apply(&delta, (off_t) strtoull(argv[4], NULL, 0),
-				   &preimage, stdout))
+				   preimage_fd, stdout))
 			return 1;
-		if (buffer_deinit(&preimage))
+		if (close(preimage_fd))
 			die_errno("cannot close preimage");
 		if (buffer_deinit(&delta))
 			die_errno("cannot close delta");
-		buffer_reset(&preimage);
 		buffer_reset(&delta);
 		return 0;
 	}
diff --git a/vcs-svn/sliding_window.c b/vcs-svn/sliding_window.c
index 5c08828..6d4261a 100644
--- a/vcs-svn/sliding_window.c
+++ b/vcs-svn/sliding_window.c
@@ -5,7 +5,7 @@
 
 #include "git-compat-util.h"
 #include "sliding_window.h"
-#include "line_buffer.h"
+#include "fd_buffer.h"
 #include "strbuf.h"
 
 static void strbuf_remove_from_left(struct strbuf *sb, size_t nbytes)
@@ -30,7 +30,7 @@ static int check_overflow(off_t a, size_t b)
 int move_window(struct view *view, off_t off, size_t len)
 {
 	off_t file_offset;
-	assert(view && view->file);
+	assert(view && view->fd >= 0);
 	assert(!check_overflow(view->off, view->buf.len));
 
 	if (check_overflow(off, len))
@@ -47,21 +47,18 @@ int move_window(struct view *view, off_t off, size_t len)
 	if (off > file_offset) {
 		/* Seek ahead to skip the gap. */
 		const off_t gap = off - file_offset;
-		const off_t nread = buffer_skip_bytes(view->file, gap);
+		const off_t nread = fd_skip_bytes(view->fd, gap);
 		if (nread != gap) {
-			if (!buffer_ferror(view->file))
+			if (!nread)
 				return error("Preimage ends early");
-			return error("Cannot seek forward in input: %s",
-				     strerror(errno));
+			return error("Cannot seek forward in input");
 		}
 		file_offset += gap;
 	}
-	buffer_read_binary(&view->buf, len - view->buf.len, view->file);
-	if (view->buf.len != len) {
-		if (!buffer_ferror(view->file))
-			return error("Preimage ends early");
-		return error("Cannot read preimage: %s", strerror(errno));
-	}
+	if (fd_read_binary(&view->buf, len - view->buf.len, view->fd))
+		return error("Cannot read preimage");
+	if (view->buf.len != len)
+		return error("Preimage ends early");
 	view->off = off;
 	return 0;
 }
diff --git a/vcs-svn/sliding_window.h b/vcs-svn/sliding_window.h
index b9f0552..532dc93 100644
--- a/vcs-svn/sliding_window.h
+++ b/vcs-svn/sliding_window.h
@@ -4,7 +4,7 @@
 #include "strbuf.h"
 
 struct view {
-	struct line_buffer *file;
+	int fd;
 	off_t off;
 	struct strbuf buf;
 };
diff --git a/vcs-svn/svndiff.c b/vcs-svn/svndiff.c
index 9ee7411..ef3a921 100644
--- a/vcs-svn/svndiff.c
+++ b/vcs-svn/svndiff.c
@@ -283,10 +283,10 @@ static int apply_one_window(struct line_buffer *delta, off_t *delta_len,
 }
 
 int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
-		   struct line_buffer *preimage, FILE *postimage)
+		   int preimage_fd, FILE *postimage)
 {
-	struct view preimage_view = {preimage, 0, STRBUF_INIT};
-	assert(delta && preimage && postimage);
+	struct view preimage_view = {preimage_fd, 0, STRBUF_INIT};
+	assert(delta && preimage_fd >= 0 && postimage);
 
 	if (read_magic(delta, &delta_len))
 		goto fail;
diff --git a/vcs-svn/svndiff.h b/vcs-svn/svndiff.h
index a986099..9003d6e 100644
--- a/vcs-svn/svndiff.h
+++ b/vcs-svn/svndiff.h
@@ -4,6 +4,6 @@
 #include "line_buffer.h"
 
 extern int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
-			  struct line_buffer *preimage, FILE *postimage);
+				int preimage_fd, FILE *postimage);
 
 #endif
-- 
1.7.2.3
Previous: Jonathan NiederNext: Jonathan Nieder
Message 32 of 40 in “svn-fe: recognize v3 dumps”
  1. 0/2 svn-fe: recognize v3 dumpsJonathan Nieder, Nov 18, 2010
  2. 1/2 vcs-svn: Error out for v3 dumpsJonathan Nieder, Nov 18, 2010
  3. 2/2 vcs-svn: Allow simple v3 dumps (no deltas yet)Jonathan Nieder, Nov 18, 2010
  4. 0/15 svn-fe: support for property deltas (but not text deltas yet)Jonathan Nieder, Nov 20, 2010
  5. 01/15 vcs-svn: Check for errors from open()Jonathan Nieder, Nov 20, 2010
  6. 02/15 vcs-svn: Eliminate node_ctx.srcRev globalJonathan Nieder, Nov 20, 2010
  7. 03/15 vcs-svn: Eliminate node_ctx.mark globalJonathan Nieder, Nov 20, 2010
  8. 04/15 vcs-svn: Unclutter handle_node by introducing have_props varJonathan Nieder, Nov 20, 2010
  9. 05/15 vcs-svn: Use mark to indicate nodes with included textJonathan Nieder, Nov 20, 2010
  10. 06/15 vcs-svn: handle_node: Handle deletion case earlyJonathan Nieder, Nov 20, 2010
  11. 07/15 vcs-svn: Replace = Delete + AddJonathan Nieder, Nov 20, 2010
  12. 08/15 vcs-svn: Combine repo_replace and repo_modify functionsJonathan Nieder, Nov 20, 2010
  13. 09/15 vcs-svn: Delay read of per-path propertiesJonathan Nieder, Nov 20, 2010
  14. 10/15 vcs-svn: Reject path nodes without Node-actionJonathan Nieder, Nov 20, 2010
  15. Jonathan NiederNov 20, 2010
  16. 11/15 vcs-svn: More dump format sanity checksJonathan Nieder, Nov 20, 2010
  17. Jonathan NiederNov 30, 2010
  18. 0/2 intermittent repo_tree corruptionJonathan Nieder, Dec 5, 2010
  19. 1/2 treap: make treap_insert return inserted nodeJonathan Nieder, Dec 5, 2010
  20. vcs-svn: Allow change nodes for root of tree (/)Jonathan Nieder, Dec 6, 2010
  21. Jonathan NiederDec 6, 2010
  22. 12/15 vcs-svn: Make source easier to read on small screensJonathan Nieder, Nov 20, 2010
  23. 13/15 vcs-svn: Split off function for handling of individual propertiesJonathan Nieder, Nov 20, 2010
  24. 14/15 vcs-svn: Sharpen parsing of property linesJonathan Nieder, Nov 20, 2010
  25. 15/15 vcs-svn: Implement Prop-delta handlingJonathan Nieder, Nov 20, 2010
  26. 0/8 svn-fe: support for text deltasJonathan Nieder, Nov 20, 2010
  27. 1/8 svn-fe: Prepare for strbuf useJonathan Nieder, Nov 20, 2010
  28. 2/8 vcs-svn: Internal fast_export_save_blob helperJonathan Nieder, Nov 20, 2010
  29. 3/8 vcs-svn: Introduce repo_read_path to check the content at a pathJonathan Nieder, Nov 20, 2010
  30. Jonathan NiederMar 6, 2011
  31. 4/8 vcs-svn: Introduce fd_buffer routinesJonathan Nieder, Nov 20, 2010
  32. 5/8 vcs-svn: Read delta preimage from file descriptorJonathan Nieder, Nov 20, 2010
  33. 6/8 vcs-svn: Let caller set up sliding window for delta preimageJonathan Nieder, Nov 20, 2010
  34. Jonathan NiederNov 20, 2010
  35. 7/8 vcs-svn: Teach line_buffer about temporary filesJonathan Nieder, Nov 20, 2010
  36. 8/8 vcs-svn: Implement text-delta handlingJonathan Nieder, Nov 20, 2010
  37. 10/8 vcs-svn: Consume whole preimage when applying deltasJonathan Nieder, Dec 4, 2010
  38. 9/8 svn-fe: Test script for handling of dumps with --deltasJonathan Nieder, Nov 20, 2010
  39. Jonathan NiederDec 4, 2010
  40. 2/2 vcs-svn: fix intermittent repo_tree corruptionJonathan Nieder, Dec 5, 2010

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.