[common] ll: make ll_push report success/failure

client/src/message.c

@@ -0,0 +1,143 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2025 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 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 General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "message.h"
+#include "core.h"
+#include "common/debug.h"
+#include "common/ll.h"
+#include "common/time.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+typedef struct MsgEvent
+{
+  uint64_t timestamp;
+  LGMsg    msg;
+}
+MsgEvent;
+
+struct MsgState
+{
+  struct ll * list;
+  struct
+  {
+    unsigned width;
+    unsigned height;
+  }
+  lastWindowSize;
+};
+
+static struct MsgState this = {0};
+
+bool lgMessage_init(void)
+{
+  this.list = ll_new();
+  if (!this.list)
+  {
+    DEBUG_ERROR("Failed to create the message list");
+    return false;
+  }
+
+  return true;
+}
+
+void lgMessage_deinit(void)
+{
+  if (this.list)
+  {
+    ll_free(this.list);
+    this.list = NULL;
+  }
+}
+
+void lgMessage_post(const LGMsg * msg)
+{
+  MsgEvent * event = (MsgEvent *)malloc(sizeof(*event));
+  if (!event)
+  {
+    DEBUG_ERROR("Out of memory");
+    return;
+  }
+
+  event->timestamp = microtime();
+  memcpy(&event->msg, msg, sizeof(event->msg));
+  if (!ll_push(this.list, event))
+  {
+    DEBUG_ERROR("Failed to post a message to the list");
+    free(event);
+  }
+}
+
+void lgMessage_process(void)
+{
+  MsgEvent * event;
+  MsgEvent * windowSize = NULL;
+
+  while(ll_shift(this.list, (void **)&event))
+  {
+    switch(event->msg.type)
+    {
+      case LG_MSG_WINDOWSIZE:
+      {
+        // retain the last/latest windowsize event
+        if (windowSize)
+          free(windowSize);
+        windowSize = event;
+        continue;
+      }
+
+      case LG_MSG_VIDEO:
+      default:
+        break;
+    }
+
+    free(event);
+  }
+
+  // if there was a windowSize event, then process it
+  if (windowSize)
+  {
+    const uint64_t time = microtime();
+    if (time - windowSize->timestamp < 500000)
+    {
+      // requeue the event for later
+      if (!ll_push(this.list, event))
+      {
+        DEBUG_ERROR("Failed to re-queue the windowSize event");
+        free(windowSize);
+      }
+    }
+    else
+    {
+      if (event->msg.windowSize.width  != this.lastWindowSize.width ||
+          event->msg.windowSize.height != this.lastWindowSize.height)
+      {
+        this.lastWindowSize.width  = event->msg.windowSize.width;
+        this.lastWindowSize.height = event->msg.windowSize.height;
+        core_onWindowSizeChanged(
+            event->msg.windowSize.width,
+            event->msg.windowSize.height);
+      }
+      free(windowSize);
+    }
+  }
+}

client/src/message.h

@@ -0,0 +1,66 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2025 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 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 General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _H_LG_MSG_
+#define _H_LG_MSG_
+
+#include <stdbool.h>
+
+typedef enum LGMsgType
+{
+  /* The LG client window size changed
+   * Note:
+   *   This message is debounced to avoid flooding the guest with resize events
+   */
+  LG_MSG_WINDOWSIZE
+}
+LGMsgType;
+
+typedef struct LGMsg
+{
+  LGMsgType type;
+  union
+  {
+    //LG_MSG_WINDOWSIZE
+    struct
+    {
+      unsigned width;
+      unsigned height;
+    }
+    windowSize;
+
+    //LG_MSG_VIDEO
+    struct
+    {
+      bool enabled;
+    }
+    video;
+  };
+}
+LGMsg;
+
+bool lgMessage_init(void);
+void lgMessage_deinit(void);
+
+void lgMessage_process(void);
+
+void lgMessage_post(const LGMsg * msg);
+
+#endif

common/include/common/ll.h

@@ -42,7 +42,7 @@ struct ll
 
 struct ll *  ll_new(void);
 void         ll_free        (struct ll * list);
-void         ll_push        (struct ll * list, void * data);
+bool         ll_push        (struct ll * list, void * data);
 bool         ll_shift       (struct ll * list, void ** data);
 bool         ll_shift_nl    (struct ll * list, void ** data);
 bool         ll_peek_head   (struct ll * list, void ** data);

common/src/ll.c

@@ -48,13 +48,13 @@ void ll_free(struct ll * list)
   free(list);
 }
 
-void ll_push(struct ll * list, void * data)
+bool ll_push(struct ll * list, void * data)
 {
   struct ll_item * item = malloc(sizeof(*item));
   if (!item)
   {
     DEBUG_ERROR("out of memory");
-    return;
+    return false;
   }
 
   item->data = data;
@@ -69,7 +69,7 @@ void ll_push(struct ll * list, void * data)
     list->head = item;
     list->tail = item;
     LG_UNLOCK(list->lock);
-    return;
+    return true;
   }
 
   item->prev = list->tail;
@@ -78,6 +78,7 @@ void ll_push(struct ll * list, void * data)
   list->tail       = item;
 
   LG_UNLOCK(list->lock);
+  return true;
 }
 
 bool ll_shift(struct ll * list, void ** data)