queue: update comments, add tryPop

Update comments on queue, and add a tryPop function which is nonblocking

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>

src/queue.zig

@@ -22,6 +22,7 @@ pub fn Queue(
 
         const Self = @This();
 
+        /// pop an item from the queue. Blocks until an item is available
         pub fn pop(self: *Self) T {
             self.mutex.lock();
             defer self.mutex.unlock();
@@ -42,8 +43,8 @@ pub fn Queue(
             return self.buf[i];
         }
 
-        /// push an item into the queue. Blocks until the message has been put
-        /// in the queue
+        /// push an item into the queue. Blocks until the item has been put in
+        /// the queue
         pub fn push(self: *Self, item: T) void {
             self.mutex.lock();
             defer self.mutex.unlock();
@@ -61,8 +62,8 @@ pub fn Queue(
             self.buf[i] = item;
         }
 
-        /// push an item into the queue. If the queue is full, this returns
-        /// immediately and the item has not been place in the queue
+        /// push an item into the queue. Returns true when the item was
+        /// successfully placed in the queue
         pub fn tryPush(self: *Self, item: T) bool {
             self.mutex.lock();
             if (self.isFull()) {
@@ -74,6 +75,17 @@ pub fn Queue(
             return true;
         }
 
+        /// pop an item from the queue. Returns null when no item is available
+        pub fn tryPop(self: *Self) ?T {
+            self.mutex.lock();
+            if (self.isEmpty()) {
+                self.mutex.unlock();
+                return null;
+            }
+            self.mutex.unlock();
+            return self.pop();
+        }
+
         /// Returns `true` if the ring buffer is empty and `false` otherwise.
         fn isEmpty(self: Self) bool {
             return self.write_index == self.read_index;