[PATCH 11/16] vcs-svn: implement copyfrom_data delta instruction
- From
David Barr <david.barr@cordelta.com>
- Date
- Mar 19, 2011, 07:20 UTC
- Message-ID
- <1300519254-20201-12-git-send-email-david.barr@cordelta.com>
- In-Reply-To
- <1300519254-20201-1-git-send-email-david.barr@cordelta.com>
From: Jonathan Nieder <jrnieder@gmail.com>
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@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Acked-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: David Barr <david.barr@cordelta.com> --- 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