New ccanlint test: _info.c must have some package documentation.

tools/ccanlint/Makefile

@@ -3,6 +3,7 @@ OBJS := tools/ccanlint/no_info.o \
 	tools/ccanlint/has_tests.o \
 	tools/ccanlint/trailing_whitespace.o \
 	tools/ccanlint/idempotent.o \
+	tools/ccanlint/has_info_documentation.o \
 
 FUTURE:=tools/ccanlint/if_have_not_ifdef.o \
 	tools/ccanlint/needs_depends.o \

tools/ccanlint/has_info_documentation.c

+#include "ccanlint.h"
+#include "../doc_extract.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 <ccan/str/str.h>
+#include <ccan/talloc/talloc.h>
+#include <ccan/noerr/noerr.h>
+#include <ccan/grab_file/grab_file.h>
+
+struct info_docs
+{
+	bool summary;
+	bool description;
+	bool example;
+};
+
+static void *check_has_info_documentation(struct manifest *m)
+{
+	struct list_head *infodocs = get_ccan_file_docs(m->info_file);
+	struct doc_section *d;
+	struct info_docs id = { false, false, false };
+
+	list_for_each(infodocs, d, list) {
+		if (!streq(d->function, m->basename))
+			continue;
+		if (streq(d->type, "summary"))
+			id.summary = true;
+		if (streq(d->type, "description"))
+			id.description = true;
+		if (streq(d->type, "example"))
+			id.example = true;
+	}
+
+	if (id.summary && id.description && id.example)
+		return NULL;
+	return talloc_memdup(m, &id, sizeof(id));
+}
+
+/* This is defined below. */
+extern struct ccanlint has_info_documentation;
+
+static void create_info_template_doc(struct manifest *m, void *check_result)
+{
+	int fd = open("_info.c.new", O_WRONLY|O_CREAT|O_EXCL, 0666);
+	FILE *new;
+	char *oldcontents;
+
+	if (fd < 0 || !(new = fdopen(fd, "w")))
+		err(1, "Creating _info.c.new to insert documentation");
+
+	if (fprintf(new,
+		    "/**"
+		    " * %s - [[ONE LINE DESCRIPTION HERE]]\n"
+		    " *\n"
+		    " * Paragraphs why %s exists and where to use it.\n"
+		    " *\n"
+		    " * Followed by an Example: section with a standalone\n"
+		    " * (trivial and usually useless) program\n"
+		    " */\n", m->basename, m->basename) < 0) {
+		unlink_noerr("_info.c.new");
+		err(1, "Writing to _info.c.new to insert documentation");
+	}
+
+	oldcontents = grab_file(m, "_info.c", NULL);
+	if (!oldcontents) {
+		unlink_noerr("_info.c.new");
+		err(1, "Reading _info.c");
+	}
+	if (fprintf(new, "%s", oldcontents) < 0) {
+		unlink_noerr("_info.c.new");
+		err(1, "Appending _info.c to _info.c.new");
+	}
+	if (fclose(new) != 0) {
+		unlink_noerr("_info.c.new");
+		err(1, "Closing _info.c.new");
+	}
+	if (rename("_info.c.new", "_info.c") != 0) {
+		unlink_noerr("_info.c.new");
+		err(1, "Renaming _info.c.new to _info.c");
+	}
+}
+
+static const char *describe_has_info_documentation(struct manifest *m,
+						   void *check_result)
+{
+	struct info_docs *id = check_result;
+	char *reason = talloc_strdup(m, "");
+
+	if (!id->summary) {
+		has_info_documentation.handle = create_info_template_doc;
+		reason = talloc_asprintf_append(reason,
+		"Your _info.c has no module documentation.\n\n"
+		"CCAN modules use /**-style comments for documentation: the\n"
+	        "overall documentation belongs in the _info.c metafile.\n");
+	}
+	if (!id->description)
+		reason = talloc_asprintf_append(reason,
+		"Your _info.c has no module description.\n\n"
+		"The lines after the first summary line in the _info.c file\n"
+		"documentation should describe the purpose and use of the\n"
+		"overall package\n");
+	if (!id->example)
+		reason = talloc_asprintf_append(reason,
+		"Your _info.c has no module example.\n\n"
+		"There should be an Example: section of the _info.c documentation\n"
+		"which provides a concise toy program which uses your module\n");
+	return reason;
+}
+
+static unsigned int has_info_documentation_score(struct manifest *m,
+						 void *check_result)
+{
+	struct info_docs *id = check_result;
+	return id->summary + id->description + id->example;
+}
+
+struct ccanlint has_info_documentation = {
+	.name = "Documentation in _info.c",
+	.total_score = 3,
+	.score = has_info_documentation_score,
+	.check = check_has_info_documentation,
+	.describe = describe_has_info_documentation,
+};