+#include <tools/ccanlint/ccanlint.h>
+#include <tools/tools.h>
+#include <ccan/talloc/talloc.h>
+#include <ccan/str/str.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <err.h>
+#include <string.h>
+#include <ctype.h>
+
+/* Creates and adds an example file. */
+static char *add_example(struct manifest *m, struct ccan_file *source,
+ bool keep,
+ struct doc_section *example)
+{
+ char *name;
+ unsigned int i;
+ int fd;
+ struct ccan_file *f;
+
+ name = maybe_temp_file(m, ".c", keep,
+ talloc_asprintf(m, "example-%s-%s",
+ source->name,
+ example->function));
+ f = new_ccan_file(m, talloc_dirname(m, name), talloc_basename(m, name));
+ talloc_steal(f, name);
+ list_add(&m->examples, &f->list);
+
+ fd = open(f->fullname, O_WRONLY | O_CREAT | O_EXCL, 0600);
+ if (fd < 0)
+ return talloc_asprintf(m, "Creating temporary file %s: %s",
+ f->fullname, strerror(errno));
+
+ for (i = 0; i < example->num_lines; i++) {
+ if (write(fd, example->lines[i], strlen(example->lines[i]))
+ != strlen(example->lines[i])
+ || write(fd, "\n", 1) != 1) {
+ close(fd);
+ return "Failure writing to temporary file";
+ }
+ }
+ close(fd);
+ return NULL;
+}
+
+/* FIXME: We should have one example per function in header. */
+struct score {
+ bool info_example, header_example;
+ char *error;
+};
+
+static void *extract_examples(struct manifest *m,
+ bool keep,
+ unsigned int *timeleft)
+{
+ struct ccan_file *f;
+ struct doc_section *d;
+ struct score *score = talloc(m, struct score);
+
+ score->info_example = score->header_example = false;
+ score->error = NULL;
+
+ list_for_each(get_ccan_file_docs(m->info_file), d, list) {
+ if (streq(d->type, "example")) {
+ score->error = add_example(m, m->info_file, keep, d);;
+ if (score->error)
+ return score;
+ score->info_example = true;
+ }
+ }
+
+ /* Check main header. */
+ list_for_each(&m->h_files, f, list) {
+ if (!strstarts(f->name, m->basename)
+ || strlen(f->name) != strlen(m->basename) + 2)
+ continue;
+
+ list_for_each(get_ccan_file_docs(f), d, list) {
+ if (streq(d->type, "example")) {
+ score->error = add_example(m, f, keep, d);
+ if (score->error)
+ return score;
+ score->header_example = true;
+ }
+ }
+ }
+ return score;
+}
+
+static unsigned int score_examples(struct manifest *m, void *check_result)
+{
+ struct score *score = check_result;
+ int total = 0;
+
+ if (score->error)
+ return 0;
+ total += score->info_example;
+ total += score->header_example;
+ return total;
+}
+
+static const char *describe_examples(struct manifest *m,
+ void *check_result)
+{
+ struct score *score = check_result;
+ char *descrip = NULL;
+
+ if (score->error)
+ return score->error;
+
+ if (!score->info_example)
+ descrip = talloc_asprintf(score,
+ "Your _info file has no module example.\n\n"
+ "There should be an Example: section of the _info documentation\n"
+ "which provides a concise toy program which uses your module\n");
+
+ if (!score->header_example)
+ descrip = talloc_asprintf(score,
+ "%sMain header file file has no examples\n\n"
+ "There should be an Example: section for each public function\n"
+ "demonstrating its use\n", descrip ? descrip : "");
+
+ return descrip;
+}
+
+struct ccanlint has_examples = {
+ .key = "has-examples",
+ .name = "_info and header files have examples",
+ .score = score_examples,
+ .check = extract_examples,
+ .describe = describe_examples,
+ .total_score = 2,
+};
+
+REGISTER_TEST(has_examples, &has_info, NULL);