thodg/libgit2

diff --git a/examples/ls-files.c b/examples/ls-files.c
new file mode 100644
index 0000000..98c89c9
--- /dev/null
+++ b/examples/ls-files.c
@@ -0,0 +1,140 @@
+/*
+ * libgit2 "ls-files" example - shows how to view all files currently in the index
+ *
+ * Written by the libgit2 contributors
+ *
+ * To the extent possible under law, the author(s) have dedicated all copyright
+ * and related and neighboring rights to this software to the public domain
+ * worldwide. This software is distributed without any warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication along
+ * with this software. If not, see
+ * <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+#include "common.h"
+#include "array.h"
+
+/**
+ * This example demonstrates the libgit2 index APIs to roughly
+ * simulate the output of `git ls-files`.
+ * `git ls-files` has many options and this currently does not show them.
+ *
+ * `git ls-files` base command shows all paths in the index at that time.
+ * This includes staged and committed files, but unstaged files will not display.
+ *
+ * This currently supports the default behavior and the `--error-unmatch` option.
+ */
+
+typedef struct {
+	int error_unmatch;
+	char *files[1024];
+	size_t file_count;
+} ls_options;
+
+static void usage(const char *message, const char *arg)
+{
+	if (message && arg)
+		fprintf(stderr, "%s: %s\n", message, arg);
+	else if (message)
+		fprintf(stderr, "%s\n", message);
+	fprintf(stderr, "usage: ls-files [--error-unmatch] [--] [<file>...]\n");
+	exit(1);
+}
+
+static int parse_options(ls_options *opts, int argc, char *argv[])
+{
+	int parsing_files = 0;
+	int i;
+
+	memset(opts, 0, sizeof(ls_options));
+
+	if (argc < 2)
+		return 0;
+
+	for (i = 1; i < argc; ++i) {
+		char *a = argv[i];
+
+		/* if it doesn't start with a '-' or is after the '--' then it is a file */
+		if (a[0] != '-' || parsing_files) {
+			parsing_files = 1;
+
+			/* watch for overflows (just in case) */
+			if (opts->file_count == 1024) {
+				fprintf(stderr, "ls-files can only support 1024 files at this time.\n");
+				return -1;
+			}
+
+			opts->files[opts->file_count++] = a;
+		} else if (!strcmp(a, "--")) {
+			parsing_files = 1;
+		} else if (!strcmp(a, "--error-unmatch")) {
+			opts->error_unmatch = 1;
+		} else {
+			usage("Unsupported argument", a);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static int print_paths(ls_options *opts, git_index *index)
+{
+	size_t i;
+	const git_index_entry *entry;
+
+	/* if there are no files explicitly listed by the user print all entries in the index */
+	if (opts->file_count == 0) {
+		size_t entry_count = git_index_entrycount(index);
+
+		for (i = 0; i < entry_count; i++) {
+			entry = git_index_get_byindex(index, i);
+			puts(entry->path);
+		}
+		return 0;
+	}
+
+	/* loop through the files found in the args and print them if they exist */
+	for (i = 0; i < opts->file_count; ++i) {
+		const char *path = opts->files[i];
+
+		if ((entry = git_index_get_bypath(index, path, GIT_INDEX_STAGE_NORMAL)) != NULL) {
+			puts(path);
+		} else if (opts->error_unmatch) {
+			fprintf(stderr, "error: pathspec '%s' did not match any file(s) known to git.\n", path);
+			fprintf(stderr, "Did you forget to 'git add'?\n");
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	ls_options opts;
+	git_repository *repo = NULL;
+	git_index *index = NULL;
+	int error;
+
+	if ((error = parse_options(&opts, argc, argv)) < 0)
+		return error;
+
+	git_libgit2_init();
+
+	if ((error = git_repository_open_ext(&repo, ".", 0, NULL)) < 0)
+		goto cleanup;
+
+	if ((error = git_repository_index(&index, repo)) < 0)
+		goto cleanup;
+
+	error = print_paths(&opts, index);
+
+cleanup:
+	git_index_free(index);
+	git_repository_free(repo);
+	git_libgit2_shutdown();
+
+	return error;
+}