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

[Ferry Huberts]

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


> +	};
>
>   	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