[PATCH] Fix mishandling of $Id$ expanded in the repository copy in convert.c
- From
- Andy Parkins <andyparkins@gmail.com>
- Date
- May 25, 2007, 10:50 UTC
- Message-ID
- <200705251150.09439.andyparkins@gmail.com>
If the repository contained an expanded ident keyword (i.e. $Id:XXXX$), then the wrong bytes were discarded, and the Id keyword was not expanded. The fault was in convert.c:ident_to_worktree().
Previously, when a "$Id:" was found in the repository version, ident_to_worktree() would search for the next "$" after this, and discarded everything it found until then. That was done with the loop:
do {
ch = *cp++;
if (ch == '$')
break;
rem--;
} while (rem);The above loop left cp pointing one character _after_ the final "$" (because of ch = *cp++). This was different from the non-expanded case, were cp is left pointing at the "$", and was different from the comment which stated "discard up to but not including the closing $". This patch fixes that by making the loop:
do {
ch = *cp;
if (ch == '$')
break;
cp++;
rem--;
} while (rem);That is, cp is tested _then_ incremented.
This loop exits if it finds a "$" or if it runs out of bytes in the source. After this loop, if there was no closing "$" the expansion is skipped, and the outer loop is allowed to continue leaving this non-keyword as it was. However, when the "$" is found, size is corrected, before running the expansion:
size -= (cp - src);
This is wrong; size is going to be corrected anyway after the expansion, so there is no need to do it here. This patch removes that redundant correction.
To help find this bug, I heavily commented the routine; those comments are included here as a bonus.
Signed-off-by: Andy Parkins <andyparkins@gmail.com> --- You wouldn't believe that I managed to get a file into the repository with $Id$ stored expanded would you? :-)
Anyway, it's fortunate that I did, because it revealed the above bugs in the ident_to_worktree() code.
I've included the comments I wrote while debugging in this patch, which I'm sure will annoy you, because you'd rather the fix and the comments separately. I'll supply that if you wish - just holler.
convert.c | 39 +++++++++++++++++++++++++++++++++++++-- 1 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/convert.c b/convert.c index 4b26b1a..3c44e3d 100644 --- a/convert.c +++ b/convert.c @@ -509,36 +509,71 @@ static char *ident_to_worktree(const char *path, const char *src, unsigned long for (dst = buf; size; size--) { const char *cp; + /* Fetch next source character, move the pointer on */ char ch = *src++; + /* Copy the current character to the destination */ *dst++ = ch; + /* If the current character is "$" or there are less than three + * remaining bytes or the two bytes following this one are not + * "Id", then simply read the next character */ if ((ch != '$') || (size < 3) || memcmp("Id", src, 2)) continue; + /* + * Here when + * - There are more than 2 bytes remaining + * - The current three bytes are "$Id$" + * with + * - ch == "$" + * - src[0] == "I" + */ + /* + * It's possible that an expanded Id has crept its way into the + * repository, we cope with that by stripping the expansion out + */ if (src[2] == ':') { + /* Expanded keywords have "$Id:" at the front */ + /* discard up to but not including the closing $ */ unsigned long rem = size - 3; + /* Point at first byte after the ":" */ cp = src + 3; + /* + * Throw away characters until either + * - we reach a "$" + * - we run out of bytes (rem == 0) + */ do { - ch = *cp++; + ch = *cp; if (ch == '$') break; + cp++; rem--; } while (rem); + /* If the above finished because it ran out of characters, then + * this is an incomplete keyword, so don't run the expansion */ if (!rem) continue; - size -= (cp - src); } else if (src[2] == '$') cp = src + 2; else + /* Anything other than "$Id:XXX$" or $Id$ and we skip the + * expansion */ continue; + /* cp is now pointing at the last $ of the keyword */ + memcpy(dst, "Id: ", 4); dst += 4; memcpy(dst, sha1_to_hex(sha1), 40); dst += 40; *dst++ = ' '; + + /* Adjust for the characters we've discarded */ size -= (cp - src); src = cp; + + /* Copy the final "$" */ *dst++ = *src++; size--; }
-- 1.5.2.763.g8c5e-dirty