ccanlint: actually try to compile examples.

Includes primitive attempt to place fragments into appropriate framework to
compile them.

tools/ccanlint/tests/examples_compile.c

+#include <tools/ccanlint/ccanlint.h>
+#include <tools/tools.h>
+#include <ccan/talloc/talloc.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+
+static const char *can_run(struct manifest *m)
+{
+	if (safe_mode)
+		return "Safe mode enabled";
+	return NULL;
+}
+
+static char *obj_list(const struct manifest *m)
+{
+	char *list;
+	struct ccan_file *i;
+
+	/* This CCAN module. */
+	list = talloc_asprintf(m, " %s.o", m->dir);
+
+	/* Other ccan modules we depend on. */
+	list_for_each(&m->dep_dirs, i, list) {
+		if (i->compiled)
+			list = talloc_asprintf_append(list, " %s", i->compiled);
+	}
+
+	return list;
+}
+
+static char *lib_list(const struct manifest *m)
+{
+	unsigned int i, num;
+	char **libs = get_libs(m, ".", &num, &m->info_file->compiled);
+	char *ret = talloc_strdup(m, "");
+
+	for (i = 0; i < num; i++)
+		ret = talloc_asprintf_append(ret, "-l%s ", libs[i]);
+	return ret;
+}
+
+static char *compile(const void *ctx,
+		     struct manifest *m,
+		     struct ccan_file *file,
+		     bool keep)
+{
+	char *errmsg;
+
+	file->compiled = maybe_temp_file(ctx, "", keep, file->fullname);
+	errmsg = compile_and_link(ctx, file->fullname, ccan_dir,
+				  obj_list(m), "", lib_list(m), file->compiled);
+	if (errmsg) {
+		talloc_free(file->compiled);
+		return errmsg;
+	}
+	return NULL;
+}
+
+struct score {
+	unsigned int score;
+	char *errors;
+};
+
+static char *start_main(char *ret)
+{
+	return talloc_asprintf_append(ret,
+				      "/* Fake function wrapper inserted */\n"
+				      "int main(int argc, char *argv[])\n"
+				      "{\n");
+}
+
+static char *mangle(struct manifest *m, struct ccan_file *example)
+{
+	char **lines = get_ccan_file_lines(example);
+	char *ret;
+	bool in_function = false, fake_function = false;
+	unsigned int i;
+
+	ret = talloc_strdup(m, "/* Prepend a heap of headers. */\n"
+			    "#include <assert.h>\n"
+			    "#include <err.h>\n"
+			    "#include <fcntl.h>\n"
+			    "#include <stdbool.h>\n"
+			    "#include <stdint.h>\n"
+			    "#include <stdio.h>\n"
+			    "#include <stdlib.h>\n"
+			    "#include <string.h>\n"
+			    "#include <sys/stat.h>\n"
+			    "#include <sys/types.h>\n"
+			    "#include <unistd.h>\n");
+	ret = talloc_asprintf_append(ret, "/* Include header from module. */\n"
+				     "#include <ccan/%s/%s.h>\n",
+				     m->basename, m->basename);
+
+	/* Starts indented?  Wrap it in a main() function. */
+	if (lines[0] && isblank(lines[0][0])) {
+		ret = start_main(ret);
+		fake_function = true;
+		in_function = true;
+	}
+
+	/* Primitive, very primitive. */
+	for (i = 0; lines[i]; i++) {
+		/* } at start of line ends a function. */
+		if (in_function) {
+			if (lines[i][0] == '}')
+				in_function = false;
+		} else {
+			/* Character at start of line, with ( and no ;
+			 * == function start. */
+			if (!isblank(lines[i][0])
+			    && strchr(lines[i], '(')
+			    && !strchr(lines[i], ';'))
+				in_function = true;
+		}
+		/* ... means elided code.  If followed by spaced line, means
+		 * next part is supposed to be inside a function. */
+		if (strcmp(lines[i], "...") == 0) {
+			if (!in_function
+			    && lines[i+1]
+			    && isblank(lines[i+1][0])) {
+				/* This implies we start a function here. */
+				ret = start_main(ret);
+				fake_function = true;
+				in_function = true;
+			}
+			ret = talloc_asprintf_append(ret,
+						     "/* ... removed */\n");
+			continue;
+		}
+		ret = talloc_asprintf_append(ret, "%s\n", lines[i]);
+	}
+
+	if (fake_function)
+		ret = talloc_asprintf_append(ret, "return 0;\n"
+					     "}\n");
+	return ret;
+}
+
+static struct ccan_file *mangle_example(struct manifest *m,
+					struct ccan_file *example, bool keep)
+{
+	char *name, *contents;
+	int fd;
+	struct ccan_file *f;
+
+	name = maybe_temp_file(example, ".c", keep, 
+			       talloc_asprintf(m, "%s/mangled-%s",
+					       m->dir, example->name));
+	f = new_ccan_file(example,
+			  talloc_dirname(example, name),
+			  talloc_basename(example, name));
+	talloc_steal(f, name);
+
+	fd = open(f->fullname, O_WRONLY | O_CREAT | O_EXCL, 0600);
+	if (fd < 0)
+		return NULL;
+
+	contents = mangle(m, example);
+	if (write(fd, contents, strlen(contents)) != strlen(contents)) {
+		close(fd);
+		return NULL;
+	}
+	close(fd);
+	return f;
+}
+
+static void *build_examples(struct manifest *m, bool keep,
+			    unsigned int *timeleft)
+{
+	struct ccan_file *i;
+	struct score *score = talloc(m, struct score);
+
+	score->score = 0;
+	score->errors = NULL;
+
+	list_for_each(&m->examples, i, list) {
+		char *ret;
+
+		examples_compile.total_score++;
+		ret = compile(score, m, i, keep);
+		if (!ret)
+			score->score++;
+		else {
+			struct ccan_file *mangle = mangle_example(m, i, keep);
+
+			talloc_free(ret);
+			ret = compile(score, m, mangle, keep);
+			if (!ret)
+				score->score++;
+			else {
+				if (!score->errors)
+					score->errors = ret;
+				else {
+					score->errors
+					= talloc_append_string(score->errors,
+							       ret);
+					talloc_free(ret);
+				}
+			}
+		}
+	}
+	return score;
+}
+
+static unsigned int score_examples(struct manifest *m, void *check_result)
+{
+	struct score *score = check_result;
+	return score->score;
+}
+
+static const char *describe(struct manifest *m, void *check_result)
+{
+	struct score *score = check_result;
+	if (verbose >= 2 && score->errors)
+		return talloc_asprintf(m, "Compile errors building examples:\n"
+				       "%s", score->errors);
+	return NULL;
+}
+
+struct ccanlint examples_compile = {
+	.key = "examples-compile",
+	.name = "Module examples compile",
+	.score = score_examples,
+	.check = build_examples,
+	.describe = describe,
+	.can_run = can_run,
+};
+
+REGISTER_TEST(examples_compile, &has_examples, NULL);