Add ueberzug support

Makefile

@@ -5,7 +5,7 @@ SRC := $(wildcard *.c)
 OBJ := $(SRC:.c=.o)
 DEP := $(OBJ:.o=.d)
 PRE := $(wildcard prev/*.sh)
-GEN := gen/prev/scripts.h
+GEN := gen/prev/scripts.h gen/server.h
 
 CFLAGS  += -Os -MD -Wall -Wextra -Wno-unused-parameter
 LDFLAGS += -lmagic
@@ -17,9 +17,9 @@ options:
 	@echo "CFLAGS  = $(CFLAGS)"
 	@echo "LDFLAGS = $(LDFLAGS)"
 
-install: ctpv
+install: ctpv ctpvclear
 	install -d $(BINPREFIX)
-	install $< $(BINPREFIX)
+	install $^ $(BINPREFIX)
 
 uninstall:
 	$(RM) $(BINPREFIX)/ctpv
@@ -35,10 +35,14 @@ ctpv: $(OBJ)
 
 ctpv.c: $(GEN)
 
-gen/prev/scripts.h: embed/embed $(PRE)
+gen/prev/scripts.h: $(PRE) embed/embed helpers.sh
 	@mkdir -p $(@D)
 	embed/embed -p prev_scr_ -h helpers.sh $(PRE) > $@
 
+gen/server.h: clear.sh end.sh embed/embed helpers.sh
+	@mkdir -p $(@D)
+	embed/embed -p scr_ -h helpers.sh clear.sh end.sh > $@
+
 embed/embed: make_embed
 	@:
 

clear.sh

@@ -0,0 +1,7 @@
+fifo="$(get_fifo "$id")"
+
+[ -e "$fifo" ] || exit 1
+
+fifo_open "$fifo" && {
+	printf '{"action": "remove", "identifier": "preview"}\n' > "$fifo"
+}

ctpv.c

@@ -1,10 +1,13 @@
+#include <stdio.h>
+#include <magic.h>
 #include <stdlib.h>
 #include <string.h>
-#include <stdio.h>
+#include <signal.h>
 #include <unistd.h>
-#include <magic.h>
 
 #include "error.h"
+#include "server.h"
+#include "preview.h"
 #include "previews.h"
 
 #define ANY_TYPE "*"
@@ -17,10 +20,13 @@ static struct {
     enum {
         MODE_PREVIEW,
         MODE_SERVER,
+        MODE_CLEAR,
+        MODE_END,
         MODE_LIST,
         MODE_MIME,
     } mode;
-} ctpv = { MODE_PREVIEW };
+    char *server_id_s;
+} ctpv = { .mode = MODE_PREVIEW };
 
 static void cleanup(void) {
     cleanup_previews();
@@ -108,15 +114,22 @@ static int preview(int argc, char *argv[])
 
     PreviewArgs args = { .f = f, .w = w, .h = h, .x = x, .y = y };
 
-    ERRCHK_RET_OK(run_preview(get_ext(f), mimetype, &args));
-
-    return OK;
+    return run_preview(get_ext(f), mimetype, &args);
 }
 
-static int server(void)
+static int server(char const *id_s)
 {
-    /* TODO */
-    return OK;
+    return server_listen(id_s);
+}
+
+static int clear(void)
+{
+    return server_clear();
+}
+
+static int end(char const *id_s)
+{
+    return server_end(id_s);
 }
 
 static int list(void)
@@ -179,10 +192,18 @@ int main(int argc, char *argv[])
     program = argc > 0 ? argv[0] : "ctpv";
 
     int c;
-    while ((c = getopt(argc, argv, "slm")) != -1) {
+    while ((c = getopt(argc, argv, "s:ce:lm")) != -1) {
         switch (c) {
         case 's':
             ctpv.mode = MODE_SERVER;
+            ctpv.server_id_s = optarg;
+            break;
+        case 'c':
+            ctpv.mode = MODE_CLEAR;
+            break;
+        case 'e':
+            ctpv.mode = MODE_END;
+            ctpv.server_id_s = optarg;
             break;
         case 'l':
             ctpv.mode = MODE_LIST;
@@ -204,7 +225,13 @@ int main(int argc, char *argv[])
             ret = preview(argc, argv);
             break;
         case MODE_SERVER:
-            ret = server();
+            ret = server(ctpv.server_id_s);
+            break;
+        case MODE_CLEAR:
+            ret = clear();
+            break;
+        case MODE_END:
+            ret = end(ctpv.server_id_s);
             break;
         case MODE_LIST:
             ret = list();

ctpvclear

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec ctpv -c

end.sh

@@ -0,0 +1,6 @@
+fifo="$(get_fifo "$1")"
+
+[ -e "$fifo" ] || exit 1
+
+# sending zero byte tells listener to stop
+fifo_open "$fifo" && printf '\0' > "$fifo"

error.h

@@ -33,12 +33,24 @@
         }                                         \
     } while (0)
 
+#define ERRCHK_GOTO(cond, ret, label, ...)        \
+    do {                                          \
+        if (cond) {                               \
+            __VA_OPT__(PRINTINTERR(__VA_ARGS__);) \
+            ret = ERR;                            \
+            goto label;                           \
+        }                                         \
+    } while (0)
+
 /*
  * Shortcut for ERRCHK_RET(expr != OK)
  */
 #define ERRCHK_RET_OK(expr, ...) \
     ERRCHK_RET((expr) != OK __VA_OPT__(, ) __VA_ARGS__)
 
+#define ERRCHK_GOTO_OK(expr, ...) \
+    ERRCHK_GOTO((expr) != OK __VA_OPT__(, ) __VA_ARGS__)
+
 enum {
     OK,
     ERR,

helpers.sh

@@ -1,3 +1,13 @@
+get_fifo() {
+	printf '/tmp/ctpvfifo.%s' "$1"
+}
+
 exists() {
 	command -v "$1" > /dev/null
 }
+
+fifo_open() {
+	# https://unix.stackexchange.com/a/522940/183147
+	dd oflag=nonblock conv=notrunc,nocreat count=0 of="$1" \
+		>/dev/null 2>/dev/null
+}

prev/image.sh

@@ -0,0 +1,13 @@
+fifo="$(get_fifo "$id")"
+
+# tell ctpv to fallback to another preview
+[ -e "$fifo" ] || exit 127
+
+path="$(printf '%s' "$f" | sed 's/\\/\\\\/g; s/"/\\"/g')"
+
+fifo_open "$fifo" && {
+	printf '{ "action": "add", "identifier": "preview", "x": %d, "y": %d, "width": %d, "height": %d, "scaler": "contain", "scaling_position_x": 1, "scaling_position_y": 1, "path": "%s"}\n' "$x" "$y" "$w" "$h" "$path" > "$fifo"
+}
+
+# tell lf to disable preview caching
+exit 1

preview.c

@@ -3,14 +3,13 @@
 
 #include "utils.h"
 #include "error.h"
+#include "shell.h"
 #include "preview.h"
 
-#define FAILED_PREVIEW_EC 127
+#define FAILED_PREVIEW_EC NOTEXIST_EC
 
 #define PREVP_SIZE sizeof(Preview *)
 
-static char shell[] = "sh";
-
 static struct {
     size_t len;
     Preview **list;
@@ -119,21 +118,20 @@ static void check_init_previews(void)
 
 static int run(Preview *p, int *exitcode)
 {
-    int pipe_fd[2];
-    ERRCHK_RET(pipe(pipe_fd) == -1, FUNCFAILED("pipe"), ERRNOS);
+    int pipe_fds[2];
+    ERRCHK_RET(pipe(pipe_fds) == -1, FUNCFAILED("pipe"), ERRNOS);
 
-    int fd = STDERR_FILENO;
-    int *sp_arg[] = { pipe_fd, &fd };
+    int sp_arg[] = { pipe_fds[0], pipe_fds[1], STDERR_FILENO };
 
-    char *args[] = { shell, "-c", p->script, shell, NULL };
+    char *args[] = SHELL_ARGS(p->script);
     int ret = spawn(args, NULL, exitcode, spawn_redirect, sp_arg);
 
-    close(pipe_fd[1]);
+    close(pipe_fds[1]);
 
     if (*exitcode != FAILED_PREVIEW_EC) {
         char buf[CMD_ERR_BUF];
         int len;
-        while ((len = read(pipe_fd[0], buf, CMD_ERR_BUF)) > 0) {
+        while ((len = read(pipe_fds[0], buf, CMD_ERR_BUF)) > 0) {
             write(STDOUT_FILENO, buf, len);
         }
 
@@ -143,7 +141,7 @@ static int run(Preview *p, int *exitcode)
         }
     }
 
-    close(pipe_fd[0]);
+    close(pipe_fds[0]);
 
     return ret;
 }
@@ -176,7 +174,7 @@ run:
     p = find_preview(mimetype, ext, &i);
     if (!p) {
         puts("ctpv: no previews found");
-        return OK;
+        return ERR;
     }
 
     ERRCHK_RET_OK(run(p, &exitcode));
@@ -185,7 +183,7 @@ run:
         goto run;
     }
 
-    return OK;
+    return exitcode == 0 ? OK : ERR;
 }
 
 Preview **get_previews_list(size_t *len)

previews.h

@@ -17,4 +17,5 @@ Preview previews[] = {
     PR(NULL,      NULL,             NULL,             any),
     PR("md",      NULL,             NULL,             markdown),
     PR(NULL,      "application",    "json",           json),
+    PR(NULL,      "image",          NULL,             image),
 };

server.c

@@ -0,0 +1,137 @@
+#include <poll.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/stat.h>
+
+#include "error.h"
+#include "utils.h"
+#include "shell.h"
+#include "gen/server.h"
+
+static pid_t ueberzug_pid;
+
+static void kill_ueberzug(void)
+{
+    if (kill(ueberzug_pid, SIGTERM) == -1) {
+        if (errno == ESRCH)
+            print_error("ueberzug is not running");
+        else
+            PRINTINTERR(FUNCFAILED("kill"), ERRNOS);
+    }
+
+    spawn_wait(ueberzug_pid, NULL);
+}
+
+static void sig_int_handler(int s)
+{
+    /* Do nothing */
+}
+
+static int listen(int fifo_fd)
+{
+    int ret = OK;
+
+    ERRCHK_GOTO(signal(SIGINT, sig_int_handler) == SIG_ERR, ret, exit,
+                FUNCFAILED("signal"), ERRNOS);
+
+    int pipe_fds[2];
+    ERRCHK_GOTO(pipe(pipe_fds) == -1, ret, signal, FUNCFAILED("pipe"), ERRNOS);
+
+    char *args[] = { "ueberzug", "layer", NULL };
+    int sp_arg[] = { pipe_fds[1], pipe_fds[0], STDIN_FILENO };
+    if (spawn(args, &ueberzug_pid, NULL, spawn_redirect, sp_arg) != OK)
+        ret = ERR;
+
+    close(pipe_fds[0]);
+
+    /* If spawn() failed */
+    if (ret != OK)
+        goto close;
+
+    struct pollfd pollfd = { .fd = fifo_fd, .events = POLLIN };
+
+    int poll_ret, len;
+    while ((poll_ret = poll(&pollfd, 1, -1) > 0)) {
+        static char buf[1024];
+        while ((len = read(fifo_fd, buf, LEN(buf))) > 0) {
+            /* First zero byte means that ctpv -e $id was run */
+            if (buf[0] == 0)
+                goto close;
+            write(pipe_fds[1], buf, len);
+        }
+    }
+
+    ERRCHK_GOTO(poll_ret < 0, ret, close, FUNCFAILED("poll"), ERRNOS);
+
+close:
+    close(pipe_fds[1]);
+    kill_ueberzug();
+
+signal:
+    signal(SIGINT, SIG_DFL);
+
+exit:
+    return ret;
+}
+
+static int check_ueberzug(int *exitcode)
+{
+    char *args[] = SHELL_ARGS("command -v ueberzug > /dev/null");
+    return spawn(args, NULL, exitcode, NULL, NULL);
+}
+
+int server_listen(char const *id_s)
+{
+    int ret = OK;
+
+    int exitcode;
+    ERRCHK_GOTO_OK(check_ueberzug(&exitcode), ret, exit);
+
+    if (exitcode == 127) {
+        print_error("ueberzug is not installed");
+        goto exit;
+    }
+
+    char fifo[256];
+    snprintf(fifo, LEN(fifo)-1, "/tmp/ctpvfifo.%s", id_s);
+
+    ERRCHK_GOTO(mkfifo(fifo, 0600) == -1 && errno != EEXIST, ret, exit,
+                FUNCFAILED("mkfifo"), ERRNOS);
+
+    int fifo_fd;
+    ERRCHK_GOTO((fifo_fd = open(fifo, O_RDONLY | O_NONBLOCK)) == -1, ret, fifo,
+                FUNCFAILED("open"), ERRNOS);
+
+    ERRCHK_GOTO_OK(listen(fifo_fd), ret, fifo_fd);
+
+fifo_fd:
+    close(fifo_fd);
+
+fifo:
+    if (remove(fifo) == -1)
+        PRINTINTERR(FUNCFAILED("remove"), ERRNOS);
+
+exit:
+    return ret;
+}
+
+int server_clear(void)
+{
+    char *args[] = SHELL_ARGS(scr_clear_sh);
+    int exitcode;
+    ERRCHK_RET_OK(spawn(args, NULL, &exitcode, NULL, NULL));
+
+    return OK;
+}
+
+int server_end(const char *id_s)
+{
+    char *args[] = SHELL_ARGS(scr_end_sh, (char *)id_s);
+    int exitcode;
+    ERRCHK_RET_OK(spawn(args, NULL, &exitcode, NULL, NULL));
+
+    return OK;
+}

server.h

@@ -0,0 +1,8 @@
+#ifndef SERVER_H
+#define SERVER_H
+
+int server_listen(char const *id_s);
+int server_clear(void);
+int server_end(const char *id_s);
+
+#endif

shell.h

@@ -0,0 +1,7 @@
+#ifndef SHELL_H
+#define SHELL_H
+
+#define SHELL_ARGS(script, ...) \
+    { "sh", "-c", script, "sh", __VA_ARGS__ __VA_OPT__(,) NULL }
+
+#endif

utils.c

@@ -10,12 +10,21 @@ char *program;
 
 int spawn_redirect(const void *arg)
 {
-    int **fds = (int **)arg;
-    int *pipe = fds[0];
-    int *fd = fds[1];
+    int *fds = (int *)arg;
 
-    ERRCHK_RET(close(pipe[0]) == -1, FUNCFAILED("close"), ERRNOS);
-    ERRCHK_RET(dup2(pipe[1], *fd) == -1, FUNCFAILED("dup2"), ERRNOS);
+    ERRCHK_RET(close(fds[0]) == -1, FUNCFAILED("close"), ERRNOS);
+    ERRCHK_RET(dup2(fds[1], fds[2]) == -1, FUNCFAILED("dup2"), ERRNOS);
+
+    return OK;
+}
+
+int spawn_wait(pid_t pid, int *exitcode)
+{
+    int stat;
+    ERRCHK_RET(waitpid(pid, &stat, 0) == -1, FUNCFAILED("waitpid"), ERRNOS);
+
+    if (exitcode && WIFEXITED(stat))
+        *exitcode = WEXITSTATUS(stat);
 
     return OK;
 }
@@ -43,20 +52,18 @@ int spawn(char *args[], pid_t *cpid, int *exitcode, int (*cfunc)(const void *),
             exit(EXIT_FAILURE);
 
         execvp(args[0], args);
+        if (errno == ENOENT)
+            exit(NOTEXIST_EC);
+
         PRINTINTERR(FUNCFAILED("exec"), ERRNOS);
         exit(EXIT_FAILURE);
     }
 
-    if (cpid) {
+    if (cpid)
         *cpid = pid;
-    } else {
-        int stat;
-        ERRCHK_RET(waitpid(pid, &stat, 0) == -1, FUNCFAILED("waitpid"),
-                   ERRNOS);
 
-        if (exitcode && WIFEXITED(stat))
-            *exitcode = WEXITSTATUS(stat);
-    }
+    if (exitcode)
+        ERRCHK_RET_OK(spawn_wait(pid, exitcode));
 
     return OK;
 }

utils.h

@@ -4,6 +4,8 @@
 #include <stdlib.h>
 #include <stdarg.h>
 
+#define NOTEXIST_EC 127
+
 #define LEN(a)    (sizeof(a) / sizeof((a)[0]))
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
@@ -27,6 +29,7 @@ typedef struct {
 extern char *program;
 
 int spawn_redirect(const void *arg);
+int spawn_wait(pid_t pid, int *exitcode);
 int spawn(char *args[], pid_t *cpid, int *exitcode, int (*cfunc)(const void *),
           const void *carg);