Add view with just window size matching

1 files changed, 79 insertions, 0 deletions

diff --git a/view.c b/view.c
new file mode 100644
index 0000000..ca7f206
--- /dev/null
+++ b/view.c
@@ -0,0 +1,79 @@
+/* Copyright (c) 2018, Curtis McEnroe <programble@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+static struct {
+    int read;
+    int write;
+} winch;
+
+static void sigwinch() {
+    struct winsize localWindow;
+    int error = ioctl(STDERR_FILENO, TIOCGWINSZ, &localWindow);
+    if (error) err(EX_IOERR, "ioctl(%d, TIOCGWINSZ, ...)", STDERR_FILENO);
+
+    ssize_t size = write(winch.write, &localWindow, sizeof(localWindow));
+    if (size < 0) err(EX_IOERR, "write(%d)", winch.write);
+    if ((size_t)size < sizeof(localWindow)) {
+        errx(EX_IOERR, "short write(%d)", winch.write);
+    }
+}
+
+int main(int argc, char *argv[]) {
+    if (argc < 2) return EX_USAGE;
+    const char *path = argv[1];
+
+    int fd = open(path, O_RDONLY);
+    if (fd < 0) err(EX_NOINPUT, "%s", path);
+
+    struct winsize remoteWindow;
+    ssize_t size = read(fd, &remoteWindow, sizeof(remoteWindow));
+    if (size < 0) err(EX_IOERR, "%s", path);
+    if ((size_t)size < sizeof(remoteWindow)) errx(EX_IOERR, "%s: short read", path);
+
+    int error = pipe((int *)&winch);
+    if (error) err(EX_OSERR, "pipe");
+
+    signal(SIGWINCH, sigwinch);
+    sigwinch();
+    for (;;) {
+        struct winsize localWindow;
+        ssize_t size = read(winch.read, &localWindow, sizeof(localWindow));
+        if (size < 0) err(EX_IOERR, "read(%d)", winch.read);
+        if ((size_t)size < sizeof(localWindow)) {
+            errx(EX_IOERR, "short read(%d)", winch.read);
+        }
+
+        if (
+            localWindow.ws_col == remoteWindow.ws_col
+            && localWindow.ws_row == remoteWindow.ws_row
+        ) break;
+
+        printf(
+            "%hux%hu -> %hux%hu\n",
+            localWindow.ws_col, localWindow.ws_row,
+            remoteWindow.ws_col, remoteWindow.ws_row
+        );
+    }
+}