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

[Ferry Huberts]

On 03/03/13 21:41, John Keeping wrote:
> On Sun, Mar 03, 2013 at 09:33:36PM +0100, Ferry Huberts wrote:
>>
>>
>> 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?
>
> Yes:
>
>      If an object that has static storage duration is not initialized
>      explicitly, then:
>      — if it has pointer type, it is initialized to a null pointer;
>      — if it has arithmetic type, it is initialized to (positive or
>        unsigned) zero;
>      — if it is an aggregate, every member is initialized (recursively)
>        according to these rules;
>      — if it is a union, the first named member is initialized
>        (recursively) according to these rules


ok. didn't know that.
maybe I'm too used to old compilers??? :-)

>
>>>
>>>>
>>>>> +	};
>>>>>
>>>>>     	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
>>
>> _______________________________________________
>> cgit mailing list
>> cgit at hjemli.net
>> http://hjemli.net/mailman/listinfo/cgit

-- 
Ferry Huberts