From: Jonathan Nieder <jrnieder@xxxxxxxxx>
The copyfrom_data instruction copies a few bytes verbatim from the
auxiliary data section of a window to the postimage.
[jn: with memory leak fix from David]
Improved-by: David Barr <david.barr@xxxxxxxxxxxx>
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
Acked-by: Ramkumar Ramachandra <artagnon@xxxxxxxxx>
Signed-off-by: David Barr <david.barr@xxxxxxxxxxxx>
---
t/t9011-svn-da.sh | 31 ++++++++++++++
vcs-svn/svndiff.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 139 insertions(+), 6 deletions(-)
diff --git a/t/t9011-svn-da.sh b/t/t9011-svn-da.sh
index e909d92..c6dbb21 100755
--- a/t/t9011-svn-da.sh
+++ b/t/t9011-svn-da.sh
@@ -140,4 +140,35 @@ test_expect_success 'reject 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 a2dd9b6..118e8c6 100644
--- a/vcs-svn/svndiff.c
+++ b/vcs-svn/svndiff.c
@@ -15,28 +15,49 @@
*
* svndiff0 ::= 'SVN\0' 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;
};
-#define WINDOW_INIT { STRBUF_INIT, STRBUF_INIT }
+#define WINDOW_INIT { STRBUF_INIT, STRBUF_INIT, STRBUF_INIT }
static void window_release(struct window *ctx)
{
+ strbuf_release(&ctx->out);
strbuf_release(&ctx->instructions);
strbuf_release(&ctx->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 delta postimage: %s", strerror(errno));
+}
+
static int error_short_read(struct line_buffer *input)
{
if (buffer_ferror(input))
@@ -93,6 +114,25 @@ static int read_int(struct line_buffer *in, uintmax_t *result, off_t *len)
return error_short_read(in);
}
+static int parse_int(const char **buf, size_t *result, const char *end)
+{
+ size_t rv = 0;
+ const char *pos;
+ for (pos = *buf; pos != end; pos++) {
+ unsigned char ch = *pos;
+
+ rv <<= VLI_BITS_PER_DIGIT;
+ rv += (ch & VLI_DIGIT_MASK);
+ if (ch & VLI_CONTINUE)
+ continue;
+
+ *result = rv;
+ *buf = pos + 1;
+ return 0;
+ }
+ return error("invalid delta: unexpected end of instructions section");
+}
+
static int read_offset(struct line_buffer *in, off_t *result, off_t *len)
{
uintmax_t val;
@@ -115,7 +155,64 @@ static int read_length(struct line_buffer *in, size_t *result, off_t *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)
+{
+ 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) { /* immediate operand */
+ *out = result;
+ return 0;
+ }
+ return parse_int(buf, out, end);
+}
+
+static int execute_one_instruction(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 *instructions;
+ size_t data_pos = 0;
+
+ /*
+ * Fill ctx->out.buf using data from the source, target,
+ * and inline data views.
+ */
+ for (instructions = ctx->instructions.buf;
+ instructions != ctx->instructions.buf + ctx->instructions.len;
+ )
+ if (execute_one_instruction(ctx, &instructions, &data_pos))
+ return -1;
+ return 0;
+}
+
+static int apply_one_window(struct line_buffer *delta, off_t *delta_len,
+ FILE *out)
{
struct window ctx = WINDOW_INIT;
size_t out_len;
@@ -130,11 +227,16 @@ static int apply_one_window(struct line_buffer *delta, off_t *delta_len)
goto error_out;
if (read_chunk(delta, delta_len, &ctx.instructions, instructions_len))
goto error_out;
- if (instructions_len) {
- error("What do you think I am? A delta applier?");
+ if (read_chunk(delta, delta_len, &ctx.data, data_len))
+ goto error_out;
+ strbuf_grow(&ctx.out, out_len);
+ if (apply_window_in_core(&ctx))
+ goto error_out;
+ if (ctx.out.len != out_len) {
+ error("invalid delta: incorrect postimage length");
goto error_out;
}
- if (read_chunk(delta, delta_len, &ctx.data, data_len))
+ if (write_strbuf(&ctx.out, out))
goto error_out;
window_release(&ctx);
return 0;
@@ -157,7 +259,7 @@ 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, pre_off, pre_len) ||
- apply_one_window(delta, &delta_len))
+ apply_one_window(delta, &delta_len, postimage))
return -1;
}
return 0;
--
1.7.3.2.846.gf4b062
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