osc: kitty notifications: updated support for icons

This implements the suggested protocol discussed in
https://github.com/kovidgoyal/kitty/issues/7657.

Icons are handled by loading a cache. Both in-band PNG data, and
symbolic names are allowed.

Applications use a graphical ID to reference the icon both when
loading the cache, and when showing a notification.

* 'g' is the graphical ID
* 'n' is optional, and assigns a symbolic name to the icon
* 'p=icon' - the payload is icon PNG data. It needs to be base64
  encoded, but this is *not* implied. I.e. the application *must* use
  e=1 explicitly.

To load an icon (in-band PNG data):

    printf '\e]99;g=123:p=icon;<base64-encoded-png-data>\e\\'

or (symbolic name)

    printf '\e]99;g=123:n=firefox:p=icon;\e\\'

Of course, we can combine the two, assigning *both* a symbolic
name, *and* PNG data:

    printf '\e]99;g=123:n=firefox:p=icon;<base64-encoded-png>\e\\'

Then, to use the icon in a notification:

    printf '\e]99;g=123;this is a notification\e\\'

Foot also allows a *symbolic* icon to be defined and used at the same
time:

    printf '\e]99;g=123:n=firefox;this is a notification\e\\'

This obviously won't work with PNG data, since it uses the payload
portion of the escape sequence.

base64.c

@@ -42,7 +42,7 @@ static const char lookup[64] = {
 };
 
 char *
-base64_decode(const char *s)
+base64_decode(const char *s, size_t *size)
 {
     const size_t len = strlen(s);
     if (unlikely(len % 4 != 0)) {
@@ -54,6 +54,9 @@ base64_decode(const char *s)
     if (unlikely(ret == NULL))
         return NULL;
 
+    if (unlikely(size != NULL))
+        *size = len / 4 * 3;
+
     for (size_t i = 0, o = 0; i < len; i += 4, o += 3) {
         unsigned a = reverse_lookup[(unsigned char)s[i + 0]];
         unsigned b = reverse_lookup[(unsigned char)s[i + 1]];
@@ -68,6 +71,13 @@ base64_decode(const char *s)
             if (unlikely(i + 4 != len || (a | b) & P || (c & P && !(d & P))))
                 goto invalid;
 
+            if (unlikely(size != NULL)) {
+                if (c & P)
+                    *size = len / 4 * 3 - 2;
+                else
+                    *size = len / 4 * 3 - 1;
+            }
+
             c &= 63;
             d &= 63;
         }

base64.h

@@ -3,6 +3,6 @@
 #include <stdint.h>
 #include <stddef.h>
 
-char *base64_decode(const char *s);
+char *base64_decode(const char *s, size_t *out_len);
 char *base64_encode(const uint8_t *data, size_t size);
 void base64_encode_final(const uint8_t *data, size_t size, char result[4]);

notify.c

@@ -10,11 +10,12 @@
 #include <fcntl.h>
 
 #define LOG_MODULE "notify"
-#define LOG_ENABLE_DBG 0
+#define LOG_ENABLE_DBG 1
 #include "log.h"
 #include "config.h"
 #include "spawn.h"
 #include "terminal.h"
+#include "util.h"
 #include "wayland.h"
 #include "xmalloc.h"
 #include "xsnprintf.h"
@@ -26,7 +27,9 @@ notify_free(struct terminal *term, struct notification *notif)
     free(notif->id);
     free(notif->title);
     free(notif->body);
-    free(notif->icon);
+    free(notif->icon_id);
+    free(notif->icon_symbolic_name);
+    free(notif->icon_data);
     free(notif->xdg_token);
     free(notif->stdout_data);
 }
@@ -167,11 +170,22 @@ notify_notify(const struct terminal *term, struct notification *notif)
 
     /* Icon: use symbolic name from notification, if present,
        otherwise fallback to the application ID */
-    const char *icon = notif->icon != NULL
+    const char *icon_name_or_path = term->app_id != NULL
-        ? notif->icon
+        ? term->app_id
-        : term->app_id != NULL
+        : term->conf->app_id;
-            ? term->app_id
+
-            : term->conf->app_id;
+    if (notif->icon_id != NULL) {
+        for (size_t i = 0; i < ALEN(term->notification_icons); i++) {
+            const struct notification_icon *icon = &term->notification_icons[i];
+
+            if (icon->id != NULL && strcmp(icon->id, notif->icon_id) == 0) {
+                icon_name_or_path = icon->symbolic_name != NULL
+                    ? icon->symbolic_name
+                    : icon->tmp_file_on_disk;
+                break;
+            }
+        }
+    }
 
     LOG_DBG("notify: title=\"%s\", body=\"%s\"", title, body);
 
@@ -201,9 +215,11 @@ notify_notify(const struct terminal *term, struct notification *notif)
 
     if (!spawn_expand_template(
             &term->conf->desktop_notifications.command, 6,
-            (const char *[]){"app-id", "window-title", "icon", "title", "body", "urgency"},
+            (const char *[]){
-            (const char *[]){term->app_id ? term->app_id : term->conf->app_id,
+                "app-id", "window-title", "icon", "title", "body", "urgency"},
-                             term->window_title, icon, title, body, urgency_str},
+            (const char *[]){
+                term->app_id ? term->app_id : term->conf->app_id,
+                term->window_title, icon_name_or_path, title, body, urgency_str},
             &argc, &argv))
     {
         return false;
@@ -254,3 +270,93 @@ notify_notify(const struct terminal *term, struct notification *notif)
     notif->stdout_fd = stdout_fds[0];
     return true;
 }
+
+static void
+add_icon(struct notification_icon *icon, const char *id, const char *symbolic_name,
+         const uint8_t *data, size_t data_sz)
+{
+    icon->id = xstrdup(id);
+    icon->symbolic_name = symbolic_name != NULL ? xstrdup(symbolic_name) : NULL;
+    icon->tmp_file_on_disk = NULL;
+
+    if (data_sz > 0) {
+        char name[64] = "/tmp/foot-notification-icon-cache-XXXXXX";
+        int fd = mkstemp(name);
+
+        if (fd < 0) {
+            LOG_ERRNO("failed to create temporary file for icon cache");
+            return;
+        }
+
+        write(fd, data, data_sz);
+        close(fd);
+
+        LOG_DBG("wrote icon data to %s", name);
+        icon->tmp_file_on_disk = xstrdup(name);
+    }
+
+    LOG_DBG("added icon to cache: %s: sym=%s, file=%s",
+            icon->id, icon->symbolic_name, icon->tmp_file_on_disk);
+}
+
+void
+notify_icon_add(struct terminal *term, const char *id,
+                const char *symbolic_name, const uint8_t *data, size_t data_sz)
+{
+#if defined(_DEBUG)
+    for (size_t i = 0; i < ALEN(term->notification_icons); i++) {
+        struct notification_icon *icon = &term->notification_icons[i];
+        if (icon->id != NULL && strcmp(icon->id, id) == 0) {
+            BUG("notification icon cache already contains \"%s\"", id);
+        }
+    }
+#endif
+
+    for (size_t i = 0; i < ALEN(term->notification_icons); i++) {
+        struct notification_icon *icon = &term->notification_icons[i];
+        if (icon->id == NULL) {
+            add_icon(icon, id, symbolic_name, data, data_sz);
+            return;
+        }
+    }
+
+    /* Cache full - throw out first entry, add new entry last */
+    notify_icon_free(&term->notification_icons[0]);
+    memmove(&term->notification_icons[0],
+            &term->notification_icons[1],
+            ((ALEN(term->notification_icons) - 1) *
+             sizeof(term->notification_icons[0])));
+
+    add_icon(
+        &term->notification_icons[ALEN(term->notification_icons) - 1],
+        id, symbolic_name, data, data_sz);
+}
+
+void
+notify_icon_del(struct terminal *term, const char *id)
+{
+    for (size_t i = 0; i < ALEN(term->notification_icons); i++) {
+        struct notification_icon *icon = &term->notification_icons[i];
+
+        if (icon->id == NULL || strcmp(icon->id, id) != 0)
+            continue;
+
+        notify_icon_free(icon);
+        return;
+    }
+}
+
+void
+notify_icon_free(struct notification_icon *icon)
+{
+    if (icon->tmp_file_on_disk != NULL)
+        unlink(icon->tmp_file_on_disk);
+
+    free(icon->id);
+    free(icon->symbolic_name);
+    free(icon->tmp_file_on_disk);
+
+    icon->id = NULL;
+    icon->symbolic_name = NULL;
+    icon->tmp_file_on_disk = NULL;
+}

notify.h

@@ -1,5 +1,6 @@
 #pragma once
 #include <stdbool.h>
+#include <stdint.h>
 #include <unistd.h>
 
 struct terminal;
@@ -29,7 +30,11 @@ struct notification {
     char *id;
     char *title;
     char *body;
-    char *icon;
+
+    char *icon_id;
+    char *icon_symbolic_name;
+    uint8_t *icon_data;
+    size_t icon_data_sz;
 
     enum notify_when when;
     enum notify_urgency urgency;
@@ -49,5 +54,17 @@ struct notification {
     size_t stdout_sz;
 };
 
+struct notification_icon {
+    char *id;
+    char *symbolic_name;
+    char *tmp_file_on_disk;
+};
+
 bool notify_notify(const struct terminal *term, struct notification *notif);
 void notify_free(struct terminal *term, struct notification *notif);
+
+void notify_icon_add(struct terminal *term, const char *id,
+                     const char *symbolic_name, const uint8_t *data,
+                     size_t data_sz);
+void notify_icon_del(struct terminal *term, const char *id);
+void notify_icon_free(struct notification_icon *icon);

osc.c

@@ -67,7 +67,7 @@ osc_to_clipboard(struct terminal *term, const char *target,
         return;
     }
 
-    char *decoded = base64_decode(base64_data);
+    char *decoded = base64_decode(base64_data, NULL);
     if (decoded == NULL) {
         if (errno == EINVAL)
             LOG_WARN("OSC: invalid clipboard data: %s", base64_data);
@@ -579,12 +579,19 @@ kitty_notification(struct terminal *term, char *string)
     payload++;
 
     char *id = xstrdup("0");       /* The 'i' parameter */
-    char *icon = NULL;             /* The 'I' parameter */
+    char *icon_id = NULL;          /* The 'g' parameter */
+    char *symbolic_icon = NULL;    /* The 'n' parameter */
     bool focus = true;             /* The 'a' parameter */
     bool report = false;           /* The 'a' parameter */
     bool done = true;              /* The 'd' parameter */
     bool base64 = false;           /* The 'e' parameter */
-    bool payload_is_title = true;  /* The 'p' parameter */
+
+    size_t payload_size;
+    enum {
+        PAYLOAD_TITLE,
+        PAYLOAD_BODY,
+        PAYLOAD_ICON,
+    } payload_type = PAYLOAD_TITLE; /* The 'p' parameter */
 
     enum notify_when when = NOTIFY_ALWAYS;
     enum notify_urgency urgency = NOTIFY_URGENCY_NORMAL;
@@ -653,9 +660,11 @@ kitty_notification(struct terminal *term, char *string)
         case 'p':
             /* payload content: title|body */
             if (strcmp(value, "title") == 0)
-                payload_is_title = true;
+                payload_type = PAYLOAD_TITLE;
             else if (strcmp(value, "body") == 0)
-                payload_is_title = false;
+                payload_type = PAYLOAD_BODY;
+            else if (strcmp(value, "icon") == 0)
+                payload_type = PAYLOAD_ICON;
             break;
 
         case 'o':
@@ -680,21 +689,26 @@ kitty_notification(struct terminal *term, char *string)
                 urgency = NOTIFY_URGENCY_CRITICAL;
             break;
 
-        /*
+        case 'g':
-         * The options below are not (yet) part of the official spec.
+            free(icon_id);
-         */
+            icon_id = xstrdup(value);
-        case 'I':
+            break;
-            /* icon: only symbolic names allowed; absolute paths are ignored */
+
-            if (value[0] != '/')
+        case 'n':
-                icon = xstrdup(value);
+            free(symbolic_icon);
+            symbolic_icon = xstrdup(value);
             break;
         }
     }
 
-    if (base64)
+    if (base64) {
-        payload = base64_decode(payload);
+        payload = base64_decode(payload, &payload_size);
-    else
+        if (payload == NULL)
+            goto out;
+    } else {
         payload = xstrdup(payload);
+        payload_size = strlen(payload);
+    }
 
     LOG_DBG("id=%s, done=%d, focus=%d, report=%d, base64=%d, icon=%s, payload: %s, "
             "honor: %s, urgency: %s, %s: %s",
@@ -724,9 +738,6 @@ kitty_notification(struct terminal *term, char *string)
     if (notif == NULL) {
         tll_push_front(term->notifications, ((struct notification){
             .id = id,
-            .icon = NULL,
-            .title = NULL,
-            .body = NULL,
             .when = when,
             .urgency = urgency,
             .focus = focus,
@@ -753,34 +764,78 @@ kitty_notification(struct terminal *term, char *string)
     if (have_u)
         notif->urgency = urgency;
 
-    if (icon != NULL) {
+    if (icon_id != NULL) {
-        free(notif->icon);
+        free(notif->icon_id);
-        notif->icon = icon;
+        notif->icon_id = icon_id;
-        icon = NULL;  /* Prevent double free */
+        icon_id = NULL;  /* Prevent double free */
     }
 
-    if (payload_is_title) {
+    if (symbolic_icon != NULL) {
-        if (notif->title == NULL) {
+        free(notif->icon_symbolic_name);
-            notif->title = payload;
+        notif->icon_symbolic_name = symbolic_icon;
+        symbolic_icon = NULL;
+    }
+
+    /* Handled chunked payload - append to existing metadata */
+    switch (payload_type) {
+    case PAYLOAD_TITLE:
+    case PAYLOAD_BODY: {
+        char **ptr = payload_type == PAYLOAD_TITLE
+            ? &notif->title
+            : &notif->body;
+
+        if (*ptr == NULL) {
+            *ptr = payload;
             payload = NULL;
         } else {
-            char *old_title = notif->title;
+            char *old = *ptr;
-            notif->title = xstrjoin(old_title, payload);
+            *ptr = xstrjoin(old, payload);
-            free(old_title);
+            free(old);
         }
-    } else {
+        break;
-        if (notif->body == NULL) {
+    }
-            notif->body = payload;
+
+    case PAYLOAD_ICON:
+        if (notif->icon_data == NULL) {
+            notif->icon_data = (uint8_t *)payload;
+            notif->icon_data_sz = payload_size;
             payload = NULL;
         } else {
-            char *old_body = notif->body;
+            notif->icon_data = xrealloc(
-            notif->body = xstrjoin(old_body, payload);
+                notif->icon_data, notif->icon_data_sz + payload_size);
-            free(old_body);
+            memcpy(&notif->icon_data[notif->icon_data_sz], payload, payload_size);
+            notif->icon_data_sz += payload_size;
         }
+        break;
     }
 
     if (done) {
-        if (!notify_notify(term, notif)) {
+        /* Update icon cache, if necessary */
+        if (notif->icon_id != NULL &&
+            (notif->icon_symbolic_name != NULL || notif->icon_data != NULL))
+        {
+            notify_icon_del(term, notif->icon_id);
+            notify_icon_add(term, notif->icon_id,
+                            notif->icon_symbolic_name,
+                            notif->icon_data, notif->icon_data_sz);
+
+            /* Don't need this anymore */
+            free(notif->icon_symbolic_name);
+            free(notif->icon_data);
+            notif->icon_symbolic_name = NULL;
+            notif->icon_data = NULL;
+            notif->icon_data_sz = 0;
+        }
+
+        /*
+         * Show notification.
+         *
+         * The checks for title|body is to handle notifications that
+         * only load icon data into the icon cache
+         */
+        if ((notif->title != NULL || notif->body != NULL) &&
+            !notify_notify(term, notif))
+        {
             tll_foreach(term->notifications, it) {
                 if (&it->item == notif) {
                     notify_free(term, &it->item);
@@ -793,7 +848,8 @@ kitty_notification(struct terminal *term, char *string)
 
 out:
     free(id);
-    free(icon);
+    free(icon_id);
+    free(symbolic_icon);
     free(payload);
 }
 

terminal.c

@@ -1823,6 +1823,9 @@ term_destroy(struct terminal *term)
         tll_remove(term->notifications, it);
     }
 
+    for (size_t i = 0; i < ALEN(term->notification_icons); i++)
+        notify_icon_free(&term->notification_icons[i]);
+
     sixel_fini(term);
 
     term_ime_reset(term);
@@ -2033,6 +2036,9 @@ term_reset(struct terminal *term, bool hard)
         tll_remove(term->notifications, it);
     }
 
+    for (size_t i = 0; i < ALEN(term->notification_icons); i++)
+        notify_icon_free(&term->notification_icons[i]);
+
     term->grapheme_shaping = term->conf->tweak.grapheme_shaping;
 
 #if defined(FOOT_IME_ENABLED) && FOOT_IME_ENABLED

terminal.h

@@ -802,6 +802,7 @@ struct terminal {
     /* Notifications that either haven't been sent yet, or have been
        sent but not yet dismissed */
     tll(struct notification) notifications;
+    struct notification_icon notification_icons[32];
 
     char *foot_exe;
     char *cwd;