Added X_noblock methods to Queue class

structio/__init__.py

@@ -6,7 +6,7 @@ from structio.core.managers.signals.sigint import SigIntManager
 from structio.core.time.clock import DefaultClock
 from structio.core.syscalls import sleep, suspend as _suspend
 from structio.core.context import TaskPool, TaskScope
-from structio.exceptions import Cancelled, TimedOut, ResourceClosed
+from structio.exceptions import Cancelled, TimedOut, ResourceClosed, ResourceBroken, ResourceBusy, WouldBlock
 from structio.core import task
 from structio.core.task import Task, TaskState
 from structio.sync import (
@@ -165,4 +165,7 @@ __all__ = [
     "get_signal_handler",
     "set_signal_handler",
     "util",
+    "ResourceBusy",
+    "ResourceBroken",
+    "WouldBlock"
 ]

structio/exceptions.py

@@ -45,3 +45,10 @@ class ResourceBroken(StructIOException):
     Raised when an asynchronous resource gets
     corrupted and is no longer usable
     """
+
+
+class WouldBlock(StructIOException):
+    """
+    Raised when a non-blocking operation
+    cannot be carried out immediately
+    """

structio/sync.py

@@ -1,7 +1,7 @@
 # Task synchronization primitives
 import structio
 from structio.core.syscalls import suspend, checkpoint
-from structio.exceptions import ResourceClosed
+from structio.exceptions import ResourceClosed, WouldBlock
 from structio.core.run import current_task, current_loop
 from structio.abc import ChannelReader, ChannelWriter, Channel
 from structio.util.ki import enable_ki_protection
@@ -138,6 +138,36 @@ class Queue:
         await checkpoint()
         return result
 
+    @enable_ki_protection
+    def get_noblock(self) -> Any:
+        """
+        Equivalent of get(), but it raises
+        structio.WouldBlock if there's no
+        elements on the queue instead of
+        blocking
+        """
+
+        if not self.container:
+            raise WouldBlock()
+        if self.putters:
+            self.putters.popleft().set()
+        return self.container.popleft()
+
+    @enable_ki_protection
+    def put_noblock(self, item: Any):
+        """
+        Equivalent of put(), but it raises
+        structio.WouldBlock if there's not
+        enough space on the queue instead
+        of blocking
+        """
+
+        if self.maxsize and len(self.container) == self.maxsize:
+            raise WouldBlock()
+        if self.getters:
+            self.getters.popleft().set()
+        self.container.append(item)
+
     def clear(self):
         """
         Clears the queue

structio/thread.py

@@ -116,6 +116,14 @@ class AsyncThreadQueue(Queue):
         self.container.append(item)
         await checkpoint()
 
+    @enable_ki_protection
+    def get_noblock(self) -> Any:
+        return super().get_noblock()
+
+    @enable_ki_protection
+    def put_noblock(self, item: Any):
+        return super().put_noblock(item)
+
     @enable_ki_protection
     def put_sync(self, item):
         """
@@ -308,8 +316,10 @@ async def run_in_worker(
             # Worker thread has exited: we no longer need to process
             # any requests, so we shut our request handler down
             handler.cancel()
-        # Fetch for the final result from the thread (this should not block)
-        success, data = await rsq.get()   # TODO: Implement get_noblock()/put_noblock()
+        # Fetch for the final result from the thread. We use get_noblock()
+        # because we know the result should already be there, so the operation
+        # should not block (and if this raises WouldBlock, then it's a bug)
+        success, data = rsq.get_noblock()
         if success:
             return data
         raise data