[PATCH 1/7] ui-blob.c: Use a context structure in walk_tree()

[Ferry Huberts]

On 03/03/13 21:25, John Keeping wrote:
> On Sun, Mar 03, 2013 at 08:56:18PM +0100, Ferry Huberts wrote:
>>
>>
>> On 03/03/13 18:06, Lukas Fleischer wrote:
>>> Do not misuse global variables to save the context. Instead, use the
>>> context pointer which was designed to share information between a
>>> read_tree_fn and the caller.
>>>
>>> This also prevents from potential misuse of the global pointers
>>> match_path and matched_sha1 after the referenced values have been
>>> overwritten on the stack.
>>>
>>> Signed-off-by: Lukas Fleischer <cgit at cryptocrack.de>
>>> ---
>>>    ui-blob.c | 42 ++++++++++++++++++++++++++----------------
>>>    1 file changed, 26 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/ui-blob.c b/ui-blob.c
>>> index 3d07ce5..4bcbc82 100644
>>> --- a/ui-blob.c
>>> +++ b/ui-blob.c
>>> @@ -11,17 +11,22 @@
>>>    #include "html.h"
>>>    #include "ui-shared.h"
>>>
>>> -static char *match_path;
>>> -static unsigned char *matched_sha1;
>>> -static int found_path;
>>> +struct walk_tree_context {
>>> +	char *match_path;
>>> +	unsigned char *matched_sha1;
>>> +	int found_path;
>>> +};
>>>
>>>    static int walk_tree(const unsigned char *sha1, const char *base, int baselen,
>>> -	const char *pathname, unsigned mode, int stage, void *cbdata) {
>>> -	if(strncmp(base, match_path, baselen)
>>> -		|| strcmp(match_path + baselen, pathname))
>>> +	const char *pathname, unsigned mode, int stage, void *cbdata)
>>> +{
>>> +	struct walk_tree_context *walk_tree_ctx = cbdata;
>>> +
>>> +	if(strncmp(base, walk_tree_ctx->match_path, baselen)
>>> +		|| strcmp(walk_tree_ctx->match_path + baselen, pathname))
>>>    		return READ_TREE_RECURSIVE;
>>> -	memmove(matched_sha1, sha1, 20);
>>> -	found_path = 1;
>>> +	memmove(walk_tree_ctx->matched_sha1, sha1, 20);
>>> +	walk_tree_ctx->found_path = 1;
>>>    	return 0;
>>>    }
>>>
>>> @@ -33,16 +38,19 @@ int cgit_print_file(char *path, const char *head)
>>>    	unsigned long size;
>>>    	struct commit *commit;
>>>    	const char *paths[] = {path, NULL};
>>> +	struct walk_tree_context walk_tree_ctx = {
>>> +		.match_path = path,
>>> +		.matched_sha1 = sha1,
>>> +		.found_path = 0
>>> +	};
>>> +
>>>    	if (get_sha1(head, sha1))
>>>    		return -1;
>>>    	type = sha1_object_info(sha1, &size);
>>>    	if(type == OBJ_COMMIT && path) {
>>>    		commit = lookup_commit_reference(sha1);
>>> -		match_path = path;
>>> -		matched_sha1 = sha1;
>>> -		found_path = 0;
>>> -		read_tree_recursive(commit->tree, "", 0, 0, paths, walk_tree, NULL);
>>> -		if (!found_path)
>>> +		read_tree_recursive(commit->tree, "", 0, 0, paths, walk_tree, &walk_tree_ctx);
>>> +		if (!walk_tree_ctx.found_path)
>>>    			return -1;
>>>    		type = sha1_object_info(sha1, &size);
>>>    	}
>>> @@ -64,6 +72,10 @@ void cgit_print_blob(const char *hex, char *path, const char *head)
>>>    	unsigned long size;
>>>    	struct commit *commit;
>>>    	const char *paths[] = {path, NULL};
>>> +	struct walk_tree_context walk_tree_ctx = {
>>> +		.match_path = path,
>>> +		.matched_sha1 = sha1,
>>
>> forgot to initialise found_path
>
> Unnecessary - C99 6.7.8:
>
>      If there are fewer initializers in a brace-enclosed list than there
>      are elements or members of an aggregate, or fewer characters in a
>      string literal used to initialize an array of known size than there
>      are elements in the array, the remainder of the aggregate shall be
>      initialized implicitly the same as objects that have static storage
>      duration.

which is what? zero?

>
>>
>>> +	};
>>>
>>>    	if (hex) {
>>>    		if (get_sha1_hex(hex, sha1)){
>>> @@ -81,9 +93,7 @@ void cgit_print_blob(const char *hex, char *path, const char *head)
>>>
>>>    	if((!hex) && type == OBJ_COMMIT && path) {
>>>    		commit = lookup_commit_reference(sha1);
>>> -		match_path = path;
>>> -		matched_sha1 = sha1;
>>> -		read_tree_recursive(commit->tree, "", 0, 0, paths, walk_tree, NULL);
>>> +		read_tree_recursive(commit->tree, "", 0, 0, paths, walk_tree, &walk_tree_ctx);
>>>    		type = sha1_object_info(sha1,&size);
>>>    	}
>>>
>>>
>>
>> --
>> Ferry Huberts

-- 
Ferry Huberts