[PATCH 05/11] vcs-svn: Read instructions from deltas

[Jonathan Nieder <jrnieder@gmail.com>]

Buffer the instruction section upon encountering it for later
interpretation.

An alternative design would involve parsing the instructions
at this point and buffering them in some processed form.  Using
the unprocessed form is simpler.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 t/t9011-svn-da.sh |    5 +++++
 vcs-svn/svndiff.c |   23 ++++++++++++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/t/t9011-svn-da.sh b/t/t9011-svn-da.sh
index 44832b0..1383263 100755
--- a/t/t9011-svn-da.sh
+++ b/t/t9011-svn-da.sh
@@ -129,4 +129,9 @@ test_expect_success 'truncated inline data' '
 	test_must_fail test-svn-fe -d preimage inline.trunc 10
 '
 
+test_expect_success 'truncated inline data (after instruction section)' '
+	printf "SVNQ%b%b%s" "QQ\001\001\003" "\0201" "b" | q_to_nul >insn.trunc &&
+	test_must_fail test-svn-fe -d preimage insn.trunc 11
+'
+
 test_done
diff --git a/vcs-svn/svndiff.c b/vcs-svn/svndiff.c
index c60d732..72fe716 100644
--- a/vcs-svn/svndiff.c
+++ b/vcs-svn/svndiff.c
@@ -24,6 +24,7 @@
 #define VLI_BITS_PER_DIGIT 7
 
 struct window {
+	struct strbuf instructions;
 	struct strbuf data;
 };
 
@@ -119,7 +120,7 @@ static int read_chunk(struct line_buffer *delta, off_t *delta_len,
 
 static int apply_one_window(struct line_buffer *delta, off_t *delta_len)
 {
-	struct window ctx = {STRBUF_INIT};
+	struct window ctx = {STRBUF_INIT, STRBUF_INIT};
 	size_t out_len;
 	size_t instructions_len;
 	size_t data_len;
@@ -131,13 +132,25 @@ static int apply_one_window(struct line_buffer *delta, off_t *delta_len)
 	    read_length(delta, &instructions_len, delta_len) ||
 	    read_length(delta, &data_len, delta_len))
 		return -1;
+	if (read_chunk(delta, delta_len, &ctx.instructions, instructions_len))
+		return error("Invalid delta: incomplete instructions section");
+	if (buffer_ferror(delta)) {
+		rv = error("Cannot read delta: %s", strerror(errno));
+		goto done;
+	}
+	if (read_chunk(delta, delta_len, &ctx.data, data_len)) {
+		rv = error("Invalid delta: incomplete data section");
+		goto done;
+	}
+	if (buffer_ferror(delta)) {
+		rv = error("Cannot read delta: %s", strerror(errno));
+		goto done;
+	}
 	if (instructions_len > 0)
 		return error("What do you think I am?  A delta applier?");
-	if (read_chunk(delta, delta_len, &ctx.data, data_len))
-		return error("Invalid delta: incomplete data section");
-	if (buffer_ferror(delta))
-		rv = error("Cannot read delta: %s", strerror(errno));
+ done:
 	strbuf_release(&ctx.data);
+	strbuf_release(&ctx.instructions);
 	return rv;
 }
 
-- 
1.7.2.3