1 files changed, 156 insertions, 0 deletions

diff --git a/www/git.causal.agency/filter.c b/www/git.causal.agency/filter.c
new file mode 100644
index 00000000..b9e7f4cd
--- /dev/null
+++ b/www/git.causal.agency/filter.c
@@ -0,0 +1,156 @@
+#include <err.h>
+#include <fcntl.h>
+#include <fnmatch.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define Q(...) #__VA_ARGS__
+
+#define MANDOC_OPTIONS "fragment,man=%N.%S,includes=../tree/%I"
+
+static int about(int argc, char *argv[]) {
+	if (argc < 2) return 1;
+	if (!fnmatch("README.[1-9]", argv[1], 0)) {
+		execlp("mandoc", "mandoc", "-T", "html", "-O", MANDOC_OPTIONS, NULL);
+		err(127, "mandoc");
+	} else if (!fnmatch("*.[1-9]", argv[1], 0)) {
+		execlp(
+			"mandoc", "mandoc", "-T", "html", "-O", "toc," MANDOC_OPTIONS, NULL
+		);
+		err(127, "mandoc");
+	} else {
+		execlp("hilex", "hilex", "-l", "text", "-f", "html", "-o", "pre", NULL);
+		err(127, "hilex");
+	}
+}
+
+static int email(void) {
+	size_t cap = 0;
+	char *buf = NULL;
+	if (getline(&buf, &cap, stdin) < 0) err(1, "getline");
+	if (buf[0] == 'C') {
+		printf("C.%s", buf + strcspn(buf, " "));
+	} else {
+		printf("%s", buf);
+	}
+	return 0;
+}
+
+static int owner(void) {
+	printf(Q(<a href="https://liberapay.com/june/donate"><img alt="Donate using Liberapay" src="https://liberapay.com/assets/widgets/donate.svg"></a>));
+	return 0;
+}
+
+#define CTAGS_PATTERN "*.[chlmy]"
+#define TEMPLATE "/tmp/filter.XXXXXXXXXX"
+
+static char tmp[PATH_MAX];
+static char tags[] = TEMPLATE;
+static void cleanup(void) {
+	unlink(tmp);
+	unlink(tags);
+}
+
+static int source(int argc, char *argv[]) {
+	if (argc < 2) return 1;
+	if (
+		strcmp("Makefile", argv[1]) &&
+		strcmp(".profile", argv[1]) &&
+		strcmp(".shrc", argv[1]) &&
+		fnmatch(CTAGS_PATTERN, argv[1], 0) &&
+		fnmatch("*.mk", argv[1], 0) &&
+		fnmatch("*.[1-9]", argv[1], 0) &&
+		fnmatch("*.sh", argv[1], 0)
+	) {
+		execlp("hilex", "hilex", "-t", "-n", argv[1], "-f", "html", NULL);
+		err(127, "hilex");
+	}
+
+	const char *ext = strrchr(argv[1], '.');
+	if (!strcmp(argv[1], ".profile") || !strcmp(argv[1], ".shrc")) {
+		ext = ".sh";
+	} else if (!strcmp(argv[1], "Makefile")) {
+		ext = ".mk";
+	} else if (!ext) {
+		ext = "";
+	}
+
+	snprintf(tmp, sizeof(tmp), TEMPLATE "%s", ext);
+	int fd = mkstemps(tmp, strlen(ext));
+	if (fd < 0) err(1, "%s", tmp);
+	atexit(cleanup);
+
+	char buf[4096];
+	for (ssize_t len; 0 < (len = read(STDIN_FILENO, buf, sizeof(buf)));) {
+		if (write(fd, buf, len) < 0) err(1, "%s", tmp);
+	}
+	if (close(fd) < 0) err(1, "%s", tmp);
+
+	fd = mkstemp(tags);
+	if (fd < 0) err(1, "%s", tags);
+	close(fd);
+	pid_t pid = fork();
+	if (pid < 0) err(1, "fork");
+	if (!pid) {
+		if (!fnmatch(CTAGS_PATTERN, argv[1], 0)) {
+			execlp("ctags", "ctags", "-w", "-f", tags, tmp, NULL);
+			warn("ctags");
+		} else {
+			execlp("mtags", "mtags", "-f", tags, tmp, NULL);
+			warn("mtags");
+		}
+		_exit(127);
+	}
+	int status;
+	if (wait(&status) < 0) err(1, "wait");
+
+	int rw[2];
+	if (pipe(rw) < 0) err(1, "pipe");
+	pid = fork();
+	if (pid < 0) err(1, "fork");
+	if (!pid) {
+		dup2(rw[1], STDOUT_FILENO);
+		close(rw[0]);
+		close(rw[1]);
+		execlp("hilex", "hilex", "-f", "html", tmp, NULL);
+		warn("hilex");
+		_exit(127);
+	}
+	pid = fork();
+	if (pid < 0) err(1, "fork");
+	if (!pid) {
+		dup2(rw[0], STDIN_FILENO);
+		close(rw[0]);
+		close(rw[1]);
+		execlp("htagml", "htagml", "-im", "-f", tags, tmp, NULL);
+		warn("htagml");
+		_exit(127);
+	}
+	close(rw[0]);
+	close(rw[1]);
+
+	if (wait(&status) < 0) err(1, "wait");
+	if (wait(&status) < 0) err(1, "wait");
+	return status;
+}
+
+int main(int argc, char *argv[]) {
+	int error;
+	switch (getprogname()[0]) {
+		break; case 'a': error = pledge("stdio exec", NULL);
+		break; case 's': error = pledge("stdio tmppath proc exec", NULL);
+		break; default:  error = pledge("stdio", NULL);
+	}
+	if (error) err(1, "pledge");
+	switch (getprogname()[0]) {
+		case 'a': return about(argc, argv);
+		case 'e': return email();
+		case 'o': return owner();
+		case 's': return source(argc, argv);
+		default: return 1;
+	}
+}