From: Jonathan Nieder <jrnieder@xxxxxxxxx>
A delta in the subversion delta (svndiff0) format consists of the
magic bytes SVN\0 followed by a sequence of windows of a certain
well specified format (starting with five integers).
Add an svndiff0_apply function and test-svn-fe -d commandline tool to
parse such a delta in the special case of not including any windows.
Later patches will add features to turn this into a fully functional
delta applier for use by svn-fe in parsing the streams produced by
"svnrdump dump" and "svnadmin dump --deltas".
The content of symlinks starts with the word "link " in Subversion's
worldview, so we will need to prepend that text for the sake of
delta application. Initialization of the input state of the
delta preimage is left to the calling program, which gives callers
a chance to seed the sliding window with text of their choice.
Improved-by: Ramkumar Ramachandra <artagnon@xxxxxxxxx>
Improved-by: David Barr <david.barr@xxxxxxxxxxxx>
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
Signed-off-by: David Barr <david.barr@xxxxxxxxxxxx>
---
Makefile | 4 +-
t/t9011-svn-da.sh | 37 ++++++++++++++++++++++++++++++++++
test-svn-fe.c | 42 ++++++++++++++++++++++++++++++++-------
vcs-svn/line_buffer.c | 6 ++--
vcs-svn/line_buffer.h | 2 +-
vcs-svn/svndiff.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++
vcs-svn/svndiff.h | 10 +++++++++
7 files changed, 139 insertions(+), 14 deletions(-)
create mode 100755 t/t9011-svn-da.sh
create mode 100644 vcs-svn/svndiff.c
create mode 100644 vcs-svn/svndiff.h
diff --git a/Makefile b/Makefile
index bac415d..bc6690a 100644
--- a/Makefile
+++ b/Makefile
@@ -1837,7 +1837,7 @@ XDIFF_OBJS = xdiff/xdiffi.o xdiff/xprepare.o xdiff/xutils.o xdiff/xemit.o \
xdiff/xmerge.o xdiff/xpatience.o
VCSSVN_OBJS = vcs-svn/line_buffer.o vcs-svn/repo_tree.o \
vcs-svn/fast_export.o vcs-svn/svndump.o \
- vcs-svn/sliding_window.o
+ vcs-svn/sliding_window.o vcs-svn/svndiff.o
VCSSVN_TEST_OBJS = test-obj-pool.o test-line-buffer.o test-treap.o
OBJECTS := $(GIT_OBJS) $(XDIFF_OBJS) $(VCSSVN_OBJS)
@@ -1963,7 +1963,7 @@ xdiff-interface.o $(XDIFF_OBJS): \
$(VCSSVN_OBJS) $(VCSSVN_TEST_OBJS): $(LIB_H) \
vcs-svn/line_buffer.h vcs-svn/repo_tree.h vcs-svn/fast_export.h \
- vcs-svn/svndump.h vcs-svn/sliding_window.h
+ vcs-svn/sliding_window.h vcs-svn/svndiff.h vcs-svn/svndump.h
test-svn-fe.o: vcs-svn/svndump.h
endif
diff --git a/t/t9011-svn-da.sh b/t/t9011-svn-da.sh
new file mode 100755
index 0000000..6d6a406
--- /dev/null
+++ b/t/t9011-svn-da.sh
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='test parsing of svndiff0 files
+
+Using the "test-svn-fe -d" helper, check that svn-fe correctly
+interprets deltas using various facilities (some from the spec,
+some only learned from practice).
+'
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+ >empty &&
+ printf foo >preimage
+'
+
+test_expect_success 'reject empty delta' '
+ test_must_fail test-svn-fe -d preimage empty 0
+'
+
+test_expect_success 'delta can empty file' '
+ printf "SVNQ" | q_to_nul >clear.delta &&
+ test-svn-fe -d preimage clear.delta 4 >actual &&
+ test_cmp empty actual
+'
+
+test_expect_success 'reject svndiff2' '
+ printf "SVN\002" >bad.filetype &&
+ test_must_fail test-svn-fe -d preimage bad.filetype 4
+'
+
+test_expect_failure 'one-window empty delta' '
+ printf "SVNQ%s" "QQQQQ" | q_to_nul >clear.onewindow &&
+ test-svn-fe -d preimage clear.onewindow 9 >actual &&
+ test_cmp empty actual
+'
+
+test_done
diff --git a/test-svn-fe.c b/test-svn-fe.c
index b42ba78..6558b52 100644
--- a/test-svn-fe.c
+++ b/test-svn-fe.c
@@ -4,15 +4,41 @@
#include "git-compat-util.h"
#include "vcs-svn/svndump.h"
+#include "vcs-svn/svndiff.h"
+#include "vcs-svn/sliding_window.h"
+#include "vcs-svn/line_buffer.h"
int main(int argc, char *argv[])
{
- if (argc != 2)
- usage("test-svn-fe <file>");
- if (svndump_init(argv[1]))
- return 1;
- svndump_read(NULL);
- svndump_deinit();
- svndump_reset();
- return 0;
+ static const char test_svnfe_usage[] =
+ "test-svn-fe (<dumpfile> | [-d] <preimage> <delta> <len>)";
+ if (argc == 2) {
+ if (svndump_init(argv[1]))
+ return 1;
+ svndump_read(NULL);
+ svndump_deinit();
+ svndump_reset();
+ return 0;
+ }
+ if (argc == 5 && !strcmp(argv[1], "-d")) {
+ struct line_buffer preimage = LINE_BUFFER_INIT;
+ struct line_buffer delta = LINE_BUFFER_INIT;
+ struct sliding_view preimage_view = SLIDING_VIEW_INIT(&preimage);
+ if (buffer_init(&preimage, argv[2]))
+ 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_view, stdout))
+ return 1;
+ if (buffer_deinit(&preimage))
+ die_errno("cannot close preimage");
+ if (buffer_deinit(&delta))
+ die_errno("cannot close delta");
+ buffer_reset(&preimage);
+ strbuf_release(&preimage_view.buf);
+ buffer_reset(&delta);
+ return 0;
+ }
+ usage(test_svnfe_usage);
}
diff --git a/vcs-svn/line_buffer.c b/vcs-svn/line_buffer.c
index 08d7cae..2f59670 100644
--- a/vcs-svn/line_buffer.c
+++ b/vcs-svn/line_buffer.c
@@ -98,10 +98,10 @@ char *buffer_read_string(struct line_buffer *buf, uint32_t len)
return ferror(buf->infile) ? NULL : buf->blob_buffer.buf;
}
-void buffer_read_binary(struct line_buffer *buf,
- struct strbuf *sb, uint32_t size)
+off_t buffer_read_binary(struct line_buffer *buf,
+ struct strbuf *sb, off_t size)
{
- strbuf_fread(sb, size, buf->infile);
+ return strbuf_fread(sb, size, buf->infile);
}
off_t buffer_copy_bytes(struct line_buffer *buf, off_t nbytes)
diff --git a/vcs-svn/line_buffer.h b/vcs-svn/line_buffer.h
index f5c468a..a253070 100644
--- a/vcs-svn/line_buffer.h
+++ b/vcs-svn/line_buffer.h
@@ -25,7 +25,7 @@ int buffer_ferror(struct line_buffer *buf);
char *buffer_read_line(struct line_buffer *buf);
char *buffer_read_string(struct line_buffer *buf, uint32_t len);
int buffer_read_char(struct line_buffer *buf);
-void buffer_read_binary(struct line_buffer *buf, struct strbuf *sb, uint32_t len);
+off_t buffer_read_binary(struct line_buffer *buf, struct strbuf *sb, off_t len);
/* Returns number of bytes read (not necessarily written). */
off_t buffer_copy_bytes(struct line_buffer *buf, off_t len);
off_t buffer_skip_bytes(struct line_buffer *buf, off_t len);
diff --git a/vcs-svn/svndiff.c b/vcs-svn/svndiff.c
new file mode 100644
index 0000000..5916036
--- /dev/null
+++ b/vcs-svn/svndiff.c
@@ -0,0 +1,52 @@
+/*
+ * Licensed under a two-clause BSD-style license.
+ * See LICENSE for details.
+ */
+
+#include "git-compat-util.h"
+#include "line_buffer.h"
+#include "svndiff.h"
+
+/*
+ * svndiff0 applier
+ *
+ * See http://svn.apache.org/repos/asf/subversion/trunk/notes/svndiff.
+ *
+ * svndiff0 ::= 'SVN\0' window*
+ */
+
+static int error_short_read(struct line_buffer *input)
+{
+ if (buffer_ferror(input))
+ return error("error reading delta: %s", strerror(errno));
+ return error("invalid delta: unexpected end of file");
+}
+
+static int read_magic(struct line_buffer *in, off_t *len)
+{
+ static const char magic[] = {'S', 'V', 'N', '\0'};
+ struct strbuf sb = STRBUF_INIT;
+
+ if (*len < sizeof(magic) ||
+ buffer_read_binary(in, &sb, sizeof(magic)) != sizeof(magic))
+ return error_short_read(in);
+
+ if (memcmp(sb.buf, magic, sizeof(magic)))
+ return error("invalid delta: unrecognized file type");
+
+ *len -= sizeof(magic);
+ strbuf_release(&sb);
+ return 0;
+}
+
+int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
+ struct sliding_view *preimage, FILE *postimage)
+{
+ assert(delta && preimage && postimage);
+
+ if (read_magic(delta, &delta_len))
+ return -1;
+ if (delta_len)
+ return error("What do you think I am? A delta applier?");
+ return 0;
+}
diff --git a/vcs-svn/svndiff.h b/vcs-svn/svndiff.h
new file mode 100644
index 0000000..74eb464
--- /dev/null
+++ b/vcs-svn/svndiff.h
@@ -0,0 +1,10 @@
+#ifndef SVNDIFF_H_
+#define SVNDIFF_H_
+
+struct line_buffer;
+struct sliding_view;
+
+extern int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
+ struct sliding_view *preimage, FILE *postimage);
+
+#endif
--
1.7.3.2.846.gf4b062
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