+#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>
+
+static const char explain[]
+= "Headers usually start with the C preprocessor lines to prevent multiple\n"
+ "inclusions. These look like the following:\n"
+ "#ifndef CCAN_<MODNAME>_H\n"
+ "#define CCAN_<MODNAME>_H\n"
+ "...\n"
+ "#endif /* CCAN_<MODNAME>_H */\n";
+
+static void fix_name(char *name)
+{
+ unsigned int i;
+
+ for (i = 0; name[i]; i++) {
+ if (isalnum(name[i]))
+ name[i] = toupper(name[i]);
+ else
+ name[i] = '_';
+ }
+}
+
+static void handle_idem(struct manifest *m, struct score *score)
+{
+ struct file_error *e;
+
+ list_for_each(&score->per_file_errors, e, list) {
+ char *name, *q, *tmpname;
+ FILE *out;
+ unsigned int i;
+
+ /* Main header gets CCAN_FOO_H, others CCAN_FOO_XXX_H */
+ if (strstarts(e->file->name, m->basename)
+ || strlen(e->file->name) == strlen(m->basename) + 2)
+ name = talloc_asprintf(score, "CCAN_%s_H", m->basename);
+ else
+ name = talloc_asprintf(score, "CCAN_%s_%s",
+ m->basename, e->file->name);
+ fix_name(name);
+
+ q = talloc_asprintf(score,
+ "Should I wrap %s in #ifndef/#define %s for you?",
+ e->file->name, name);
+ if (!ask(q))
+ continue;
+
+ tmpname = maybe_temp_file(score, ".h", false, e->file->name);
+ out = fopen(tmpname, "w");
+ if (!out)
+ err(1, "Opening %s", tmpname);
+ if (fprintf(out, "#ifndef %s\n#define %s\n", name, name) < 0)
+ err(1, "Writing %s", tmpname);
+
+ for (i = 0; i < e->file->num_lines; i++)
+ if (fprintf(out, "%s\n", e->file->lines[i]) < 0)
+ err(1, "Writing %s", tmpname);
+
+ if (fprintf(out, "#endif /* %s */\n", name) < 0)
+ err(1, "Writing %s", tmpname);
+
+ if (fclose(out) != 0)
+ err(1, "Closing %s", tmpname);
+
+ if (!move_file(tmpname, e->file->fullname))
+ err(1, "Moving %s to %s", tmpname, e->file->fullname);
+ }
+}
+
+static bool check_idem(struct ccan_file *f, struct score *score)
+{
+ struct line_info *line_info;
+ unsigned int i, first_preproc_line;
+ const char *line, *sym;
+
+ line_info = get_ccan_line_info(f);
+ if (f->num_lines < 3)
+ /* FIXME: We assume small headers probably uninteresting. */
+ return true;
+
+ for (i = 0; i < f->num_lines; i++) {
+ if (line_info[i].type == DOC_LINE
+ || line_info[i].type == COMMENT_LINE)
+ continue;
+ if (line_info[i].type == CODE_LINE) {
+ score_file_error(score, f, i+1,
+ "Expect first non-comment line to be"
+ " #ifndef.");
+ return false;
+ } else if (line_info[i].type == PREPROC_LINE)
+ break;
+ }
+
+ /* No code at all? Don't complain. */
+ if (i == f->num_lines)
+ return true;
+
+ first_preproc_line = i;
+ for (i = first_preproc_line+1; i < f->num_lines; i++) {
+ if (line_info[i].type == DOC_LINE
+ || line_info[i].type == COMMENT_LINE)
+ continue;
+ if (line_info[i].type == CODE_LINE) {
+ score_file_error(score, f, i+1,
+ "Expect second non-comment line to be"
+ " #define.");
+ return false;
+ } else if (line_info[i].type == PREPROC_LINE)
+ break;
+ }
+
+ /* No code at all? Weird. */
+ if (i == f->num_lines)
+ return true;
+
+ /* We expect a condition on this line. */
+ if (!line_info[i].cond) {
+ score_file_error(score, f, i+1, "Expected #ifndef");
+ return false;
+ }
+
+ line = f->lines[i];
+
+ /* We expect the condition to be ! IFDEF <symbol>. */
+ if (line_info[i].cond->type != PP_COND_IFDEF
+ || !line_info[i].cond->inverse) {
+ score_file_error(score, f, i+1, "Expected #ifndef");
+ return false;
+ }
+
+ /* And this to be #define <symbol> */
+ if (!get_token(&line, "#"))
+ abort();
+ if (!get_token(&line, "define")) {
+ char *str = talloc_asprintf(score,
+ "expected '#define %s'",
+ line_info[i].cond->symbol);
+ score_file_error(score, f, i+1, str);
+ return false;
+ }
+ sym = get_symbol_token(f, &line);
+ if (!sym || !streq(sym, line_info[i].cond->symbol)) {
+ char *str = talloc_asprintf(score,
+ "expected '#define %s'",
+ line_info[i].cond->symbol);
+ score_file_error(score, f, i+1, str);
+ return false;
+ }
+
+ /* Rest of code should all be covered by that conditional. */
+ for (i++; i < f->num_lines; i++) {
+ unsigned int val = 0;
+ if (line_info[i].type == DOC_LINE
+ || line_info[i].type == COMMENT_LINE)
+ continue;
+ if (get_ccan_line_pp(line_info[i].cond, sym, &val, NULL)
+ != NOT_COMPILED) {
+ score_file_error(score, f, i+1, "code outside"
+ " idempotent region");
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static void check_idempotent(struct manifest *m,
+ bool keep,
+ unsigned int *timeleft, struct score *score)
+{
+ struct ccan_file *f;
+
+ list_for_each(&m->h_files, f, list) {
+ if (!check_idem(f, score))
+ score->error = "Headers are not idempotent";
+ }
+ if (!score->error) {
+ score->pass = true;
+ score->score = score->total;
+ }
+}
+
+struct ccanlint headers_idempotent = {
+ .key = "headers_idempotent",
+ .name = "Module headers are #ifndef/#define wrapped",
+ .check = check_idempotent,
+ .handle = handle_idem,
+ .needs = ""
+};
+
+REGISTER_TEST(headers_idempotent);