The copyfrom_data instruction copies a few bytes verbatim from the
auxiliary data section of a window to the postimage.
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
---
t/t9011-svn-da.sh | 31 +++++++++++++++++++
vcs-svn/svndiff.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 112 insertions(+), 5 deletions(-)
diff --git a/t/t9011-svn-da.sh b/t/t9011-svn-da.sh
index 1383263..9279924 100755
--- a/t/t9011-svn-da.sh
+++ b/t/t9011-svn-da.sh
@@ -134,4 +134,35 @@ test_expect_success 'truncated inline data (after instruction section)' '
test_must_fail test-svn-fe -d preimage insn.trunc 11
'
+test_expect_success 'copyfrom_data' '
+ echo hi >expect &&
+ printf "SVNQ%b%b%b" "QQ\003\001\003" "\0203" "hi\n" | q_to_nul >copydat &&
+ test-svn-fe -d preimage copydat 13 >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'multiple copyfrom_data' '
+ echo hi >expect &&
+ printf "SVNQ%b%b%b%b%b" "QQ\003\002\003" "\0201\0202" "hi\n" \
+ "QQQ\002Q" "\0200Q" | q_to_nul >copy.multi &&
+ len=$(wc -c <copy.multi) &&
+ test-svn-fe -d preimage copy.multi $len >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'incomplete multiple insn' '
+ printf "SVNQ%b%b%b" "QQ\003\002\003" "\0203\0200" "hi\n" |
+ q_to_nul >copy.partial &&
+ len=$(wc -c <copy.partial) &&
+ test_must_fail test-svn-fe -d preimage copy.partial $len
+'
+
+test_expect_success 'catch attempt to copy missing data' '
+ printf "SVNQ%b%b%s%b%s" "QQ\002\002\001" "\0201\0201" "X" \
+ "QQQQ\002" "YZ" |
+ q_to_nul >copy.incomplete &&
+ len=$(wc -c <copy.incomplete) &&
+ test_must_fail test-svn-fe -d preimage copy.incomplete $len
+'
+
test_done
diff --git a/vcs-svn/svndiff.c b/vcs-svn/svndiff.c
index 72fe716..ac776e0 100644
--- a/vcs-svn/svndiff.c
+++ b/vcs-svn/svndiff.c
@@ -14,20 +14,40 @@
*
* svndiff0 ::= 'SVN\0' window window*;
* window ::= int int int int int instructions inline_data;
+ * instructions ::= instruction*;
+ * instruction ::= view_selector int int
+ * | copyfrom_data int
+ * | packed_view_selector int
+ * | packed_copyfrom_data
+ * ;
+ * copyfrom_data ::= # binary 10 000000;
+ * packed_copyfrom_data ::= # copyfrom_data OR-ed with 6 bit value;
* int ::= highdigit* lowdigit;
* highdigit ::= # binary 1000 0000 OR-ed with 7 bit value;
* lowdigit ::= # 7 bit value;
*/
+#define INSN_MASK 0xc0
+#define INSN_COPYFROM_DATA 0x80
+#define OPERAND_MASK 0x3f
+
#define VLI_CONTINUE 0x80
#define VLI_DIGIT_MASK 0x7f
#define VLI_BITS_PER_DIGIT 7
struct window {
+ struct strbuf out;
struct strbuf instructions;
struct strbuf data;
};
+static int write_strbuf(struct strbuf *sb, FILE *out)
+{
+ if (fwrite(sb->buf, 1, sb->len, out) == sb->len) /* Success. */
+ return 0;
+ return error("Cannot write: %s\n", strerror(errno));
+}
+
static int read_magic(struct line_buffer *in, off_t *len)
{
static const char magic[] = {'S', 'V', 'N', '\0'};
@@ -118,9 +138,63 @@ static int read_chunk(struct line_buffer *delta, off_t *delta_len,
return 0;
}
-static int apply_one_window(struct line_buffer *delta, off_t *delta_len)
+static int copyfrom_data(struct window *ctx, size_t *data_pos, size_t nbytes)
{
- struct window ctx = {STRBUF_INIT, STRBUF_INIT};
+ const size_t pos = *data_pos;
+ if (unsigned_add_overflows(pos, nbytes) ||
+ pos + nbytes > ctx->data.len)
+ return error("Invalid delta: copies unavailable inline data.");
+ strbuf_add(&ctx->out, ctx->data.buf + pos, nbytes);
+ *data_pos += nbytes;
+ return 0;
+}
+
+static int parse_first_operand(const char **buf, size_t *out, const char *end)
+{
+ size_t result = (unsigned char) *(*buf)++ & OPERAND_MASK;
+ if (result) {
+ *out = result;
+ return 0;
+ }
+ return parse_int(buf, out, end);
+}
+
+static int step(struct window *ctx, const char **instructions, size_t *data_pos)
+{
+ unsigned int instruction;
+ const char *insns_end = ctx->instructions.buf + ctx->instructions.len;
+ size_t nbytes;
+ assert(ctx);
+ assert(instructions && *instructions);
+ assert(data_pos);
+
+ instruction = (unsigned char) **instructions;
+ if (parse_first_operand(instructions, &nbytes, insns_end))
+ return -1;
+ if ((instruction & INSN_MASK) != INSN_COPYFROM_DATA)
+ return error("Unknown instruction %x", instruction);
+ return copyfrom_data(ctx, data_pos, nbytes);
+}
+
+static int apply_window_in_core(struct window *ctx)
+{
+ const char *insn = ctx->instructions.buf;
+ size_t data_pos = 0;
+
+ /*
+ * Populate ctx->out.buf using data from the source, target,
+ * and inline data views.
+ */
+ while (insn != ctx->instructions.buf + ctx->instructions.len)
+ if (step(ctx, &insn, &data_pos))
+ return -1;
+ return 0;
+}
+
+static int apply_one_window(struct line_buffer *delta, off_t *delta_len,
+ FILE *out)
+{
+ struct window ctx = {STRBUF_INIT, STRBUF_INIT, STRBUF_INIT};
size_t out_len;
size_t instructions_len;
size_t data_len;
@@ -146,8 +220,10 @@ static int apply_one_window(struct line_buffer *delta, off_t *delta_len)
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 (apply_window_in_core(&ctx) || write_strbuf(&ctx.out, out)) {
+ rv = -1;
+ goto done;
+ }
done:
strbuf_release(&ctx.data);
strbuf_release(&ctx.instructions);
@@ -168,7 +244,7 @@ int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
if (read_offset(delta, &pre_off, &delta_len) ||
read_length(delta, &pre_len, &delta_len) ||
move_window(&preimage_view, pre_off, pre_len) ||
- apply_one_window(delta, &delta_len))
+ apply_one_window(delta, &delta_len, postimage))
goto fail;
if (delta_len && buffer_at_eof(delta)) {
error("Delta ends early! (%"PRIu64" bytes remaining)",
--
1.7.2.3
--
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