X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan_tools%2Fccanlint%2Fidempotent.c;fp=ccan_tools%2Fccanlint%2Fidempotent.c;h=4456557516b6c414d36a57102a007311be9d2da0;hp=0000000000000000000000000000000000000000;hb=c8acddea39d222312102952e91c32cfe4dd2cea0;hpb=89afb563a8fea1e1c6d4bbcc6b1c51aa6cc8f045

diff --git a/ccan_tools/ccanlint/idempotent.c b/ccan_tools/ccanlint/idempotent.c
new file mode 100644
index 00000000..44565575
--- /dev/null
+++ b/ccan_tools/ccanlint/idempotent.c
@@ -0,0 +1,71 @@
+#include "ccanlint.h"
+#include <talloc/talloc.h>
+#include <string/string.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>
+
+static const char explain[] 
+= "Headers usually start with the C preprocessor lines to prevent multiple\n"
+  "inclusions.  These look like the following:\n"
+  "#ifndef MY_HEADER_H\n"
+  "#define MY_HEADER_H\n"
+  "...\n"
+  "#endif /* MY_HEADER_H */\n";
+
+static char *report_idem(struct ccan_file *f, char *sofar)
+{
+	char **lines;
+	char *secondline;
+
+	lines = get_ccan_file_lines(f);
+	if (f->num_lines < 3)
+		/* FIXME: We assume small headers probably uninteresting. */
+		return NULL;
+
+	if (!strstarts(lines[0], "#ifndef "))
+		return talloc_asprintf_append(sofar,
+			"%s:1:expect first line to be #ifndef.\n", f->name);
+
+	secondline = talloc_asprintf(f, "#define %s",
+				     lines[0] + strlen("#ifndef "));
+	if (!streq(lines[1], secondline))
+		return talloc_asprintf_append(sofar,
+			"%s:2:expect second line to be '%s'.\n",
+			f->name, secondline);
+
+	return sofar;
+}
+
+static void *check_idempotent(struct manifest *m)
+{
+	struct ccan_file *f;
+	char *report = NULL;
+
+	list_for_each(&m->h_files, f, list)
+		report = report_idem(f, report);
+
+	return report;
+}
+
+static const char *describe_idempotent(struct manifest *m, void *check_result)
+{
+	return talloc_asprintf(check_result, 
+			       "Some headers not idempotent:\n"
+			       "%s\n%s", (char *)check_result,
+			       explain);
+}
+
+struct ccanlint idempotent = {
+	.name = "Headers are #ifndef/#define idempotent wrapped",
+	.total_score = 1,
+	.check = check_idempotent,
+	.describe = describe_idempotent,
+};