Merge branch 'cb/maint-rev-list-verify-object'

[git.git] / vcs-svn / svndiff.c

diff --git a/vcs-svn/svndiff.c b/vcs-svn/svndiff.c
index ed1d4a08be83b2255fb967b628d24483ba782a5c..1647c1a780c5a6153455fdc73b6e422b474dab8e 100644 (file)
--- a/vcs-svn/svndiff.c
+++ b/vcs-svn/svndiff.c
@@ -21,7 +21,13 @@
  *   | packed_view_selector int
  *   | packed_copyfrom_data
  *   ;
+ * view_selector ::= copyfrom_source
+ *   | copyfrom_target
+ *   ;
+ * copyfrom_source ::= # binary 00 000000;
+ * copyfrom_target ::= # binary 01 000000;
  * copyfrom_data ::= # binary 10 000000;
+ * packed_view_selector ::= # view_selector OR-ed with 6 bit value;
  * packed_copyfrom_data ::= # copyfrom_data OR-ed with 6 bit value;
  * int ::= highdigit* lowdigit;
  * highdigit ::= # binary 1000 0000 OR-ed with 7 bit value;
@@ -29,6 +35,8 @@
  */
 
 #define INSN_MASK      0xc0
+#define INSN_COPYFROM_SOURCE   0x00
+#define INSN_COPYFROM_TARGET   0x40
 #define INSN_COPYFROM_DATA     0x80
 #define OPERAND_MASK   0x3f
 
@@ -37,12 +45,13 @@
 #define VLI_BITS_PER_DIGIT 7
 
 struct window {
+       struct sliding_view *in;
        struct strbuf out;
        struct strbuf instructions;
        struct strbuf data;
 };
 
-#define WINDOW_INIT    { STRBUF_INIT, STRBUF_INIT, STRBUF_INIT }
+#define WINDOW_INIT(w) { (w), STRBUF_INIT, STRBUF_INIT, STRBUF_INIT }
 
 static void window_release(struct window *ctx)
 {
@@ -155,6 +164,32 @@ static int read_length(struct line_buffer *in, size_t *result, off_t *len)
        return 0;
 }
 
+static int copyfrom_source(struct window *ctx, const char **instructions,
+                          size_t nbytes, const char *insns_end)
+{
+       size_t offset;
+       if (parse_int(instructions, &offset, insns_end))
+               return -1;
+       if (unsigned_add_overflows(offset, nbytes) ||
+           offset + nbytes > ctx->in->width)
+               return error("invalid delta: copies source data outside view");
+       strbuf_add(&ctx->out, ctx->in->buf.buf + offset, nbytes);
+       return 0;
+}
+
+static int copyfrom_target(struct window *ctx, const char **instructions,
+                          size_t nbytes, const char *instructions_end)
+{
+       size_t offset;
+       if (parse_int(instructions, &offset, instructions_end))
+               return -1;
+       if (offset >= ctx->out.len)
+               return error("invalid delta: copies from the future");
+       for (; nbytes > 0; nbytes--)
+               strbuf_addch(&ctx->out, ctx->out.buf[offset++]);
+       return 0;
+}
+
 static int copyfrom_data(struct window *ctx, size_t *data_pos, size_t nbytes)
 {
        const size_t pos = *data_pos;
@@ -189,9 +224,16 @@ static int execute_one_instruction(struct window *ctx,
        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);
+       switch (instruction & INSN_MASK) {
+       case INSN_COPYFROM_SOURCE:
+               return copyfrom_source(ctx, instructions, nbytes, insns_end);
+       case INSN_COPYFROM_TARGET:
+               return copyfrom_target(ctx, instructions, nbytes, insns_end);
+       case INSN_COPYFROM_DATA:
+               return copyfrom_data(ctx, data_pos, nbytes);
+       default:
+               return error("invalid delta: unrecognized instruction");
+       }
 }
 
 static int apply_window_in_core(struct window *ctx)
@@ -208,13 +250,15 @@ static int apply_window_in_core(struct window *ctx)
             )
                if (execute_one_instruction(ctx, &instructions, &data_pos))
                        return -1;
+       if (data_pos != ctx->data.len)
+               return error("invalid delta: does not copy all inline data");
        return 0;
 }
 
 static int apply_one_window(struct line_buffer *delta, off_t *delta_len,
-                           FILE *out)
+                           struct sliding_view *preimage, FILE *out)
 {
-       struct window ctx = WINDOW_INIT;
+       struct window ctx = WINDOW_INIT(preimage);
        size_t out_len;
        size_t instructions_len;
        size_t data_len;
@@ -251,13 +295,13 @@ int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
        if (read_magic(delta, &delta_len))
                return -1;
        while (delta_len) {     /* For each window: */
-               off_t pre_off;
+               off_t pre_off = pre_off; /* stupid GCC... */
                size_t pre_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, postimage))
+                   apply_one_window(delta, &delta_len, preimage, postimage))
                        return -1;
        }
        return 0;