path: root/Documentation/technical/api-string-list.txt
diff options
authorJohannes Schindelin <>2008-07-21 18:03:49 (GMT)
committerJunio C Hamano <>2008-07-22 02:11:50 (GMT)
commitc455c87c5cd42bbbe586b31cea1143132f3a39e4 (patch)
tree5271cd3b8b7be270c78612047f42ff6fd47e4bbe /Documentation/technical/api-string-list.txt
parent51ef1daa4a0dfaa4d777b2fa949ba051cf800554 (diff)
Rename path_list to string_list
The name path_list was correct for the first usage of that data structure, but it really is a general-purpose string list. $ perl -i -pe 's/path-list/string-list/g' $(git grep -l path-list) $ perl -i -pe 's/path_list/string_list/g' $(git grep -l path_list) $ git mv path-list.h string-list.h $ git mv path-list.c string-list.c $ perl -i -pe 's/has_path/has_string/g' $(git grep -l has_path) $ perl -i -pe 's/path/string/g' string-list.[ch] $ git mv Documentation/technical/api-path-list.txt \ Documentation/technical/api-string-list.txt $ perl -i -pe 's/strdup_paths/strdup_strings/g' $(git grep -l strdup_paths) ... and then fix all users of string-list to access the member "string" instead of "path". Documentation/technical/api-string-list.txt needed some rewrapping, too. Signed-off-by: Johannes Schindelin <> Signed-off-by: Junio C Hamano <>
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+string-list API
+The string_list API offers a data structure and functions to handle sorted
+and unsorted string lists.
+The 'string_list' struct used to be called 'path_list', but was renamed
+because it is not specific to paths.
+The caller:
+. Allocates and clears a `struct string_list` variable.
+. Initializes the members. You might want to set the flag `strdup_strings`
+ if the strings should be strdup()ed. For example, this is necessary
+ when you add something like git_path("..."), since that function returns
+ a static buffer that will change with the next call to git_path().
+If you need something advanced, you can manually malloc() the `items`
+member (you need this if you add things later) and you should set the
+`nr` and `alloc` members in that case, too.
+. Adds new items to the list, using `string_list_append` or
+ `string_list_insert`.
+. Can check if a string is in the list using `string_list_has_string` or
+ `unsorted_string_list_has_string` and get it from the list using
+ `string_list_lookup` for sorted lists.
+. Can sort an unsorted list using `sort_string_list`.
+. Finally it should free the list using `string_list_clear`.
+struct string_list list;
+int i;
+memset(&list, 0, sizeof(struct string_list));
+string_list_append("foo", &list);
+string_list_append("bar", &list);
+for (i = 0; i <; i++)
+ printf("%s\n", list.items[i].path)
+NOTE: It is more efficient to build an unsorted list and sort it
+afterwards, instead of building a sorted list (`O(n log n)` instead of
+However, if you use the list to check if a certain string was added
+already, you should not do that (using unsorted_string_list_has_string()),
+because the complexity would be quadratic again (but with a worse factor).
+* General ones (works with sorted and unsorted lists as well)
+ Dump a string_list to stdout, useful mainly for debugging purposes. It
+ can take an optional header argument and it writes out the
+ string-pointer pairs of the string_list, each one in its own line.
+ Free a string_list. The `string` pointer of the items will be freed in
+ case the `strdup_strings` member of the string_list is set. The second
+ parameter controls if the `util` pointer of the items should be freed
+ or not.
+* Functions for sorted lists only
+ Determine if the string_list has a given string or not.
+ Insert a new element to the string_list. The returned pointer can be
+ handy if you want to write something to the `util` pointer of the
+ string_list_item containing the just added string.
+Since this function uses xrealloc() (which die()s if it fails) if the
+list needs to grow, it is safe not to check the pointer. I.e. you may
+write `string_list_insert(...)->util = ...;`.
+ Look up a given string in the string_list, returning the containing
+ string_list_item. If the string is not found, NULL is returned.
+* Functions for unsorted lists only
+ Append a new string to the end of the string_list.
+ Make an unsorted list sorted.
+ It's like `string_list_has_string()` but for unsorted lists.
+This function needs to look through all items, as opposed to its
+counterpart for sorted lists, which performs a binary search.
+Data structures
+* `struct string_list_item`
+Represents an item of the list. The `path` member is a pointer to the
+string, and you may use the `util` member for any purpose, if you want.
+* `struct string_list`
+Represents the list itself.
+. The array of items are available via the `items` member.
+. The `nr` member contains the number of items stored in the list.
+. The `alloc` member is used to avoid reallocating at every insertion.
+ You should not tamper with it.
+. Setting the `strdup_strings` member to 1 will strdup() the strings
+ before adding them, see above.