equals/hashCode for wrapper CoroutineDispatcher impls

Author: elizarov

kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/Builders.kt

@@ -89,8 +89,9 @@ public suspend fun <T> run(context: CoroutineContext, block: suspend () -> T): T
         // fast path #2 if the result is actually the same
         if (newContext === oldContext)
             return@sc block.startCoroutineUninterceptedOrReturn(cont)
-        // fast path #3 if the new dispatcher is the same as the old one
-        if (newContext[ContinuationInterceptor] === oldContext[ContinuationInterceptor]) {
+        // fast path #3 if the new dispatcher is the same as the old one.
+        // `equals` is used by design (see equals implementation is wrapper context like ExecutorCoroutineDispatcher)
+        if (newContext[ContinuationInterceptor] == oldContext[ContinuationInterceptor]) {
             val newContinuation = RunContinuationDirect(newContext, cont)
             return@sc block.startCoroutineUninterceptedOrReturn(newContinuation)
         }

kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/Executors.kt

@@ -37,7 +37,7 @@ public fun Executor.toCoroutineDispatcher(): CoroutineDispatcher =
 public fun Executor.asCoroutineDispatcher(): CoroutineDispatcher =
     ExecutorCoroutineDispatcher(this)
 
-internal open class ExecutorCoroutineDispatcher(
+private class ExecutorCoroutineDispatcher(
     private val executor: Executor
 ) : CoroutineDispatcher(), Delay {
     override fun dispatch(context: CoroutineContext, block: Runnable) = executor.execute(block)
@@ -55,6 +55,10 @@ internal open class ExecutorCoroutineDispatcher(
             scheduledExecutor.schedule(block, time, unit)
         return DisposableFutureHandle(timeout)
     }
+
+    override fun toString(): String = executor.toString()
+    override fun equals(other: Any?): Boolean = other is ExecutorCoroutineDispatcher && other.executor === executor
+    override fun hashCode(): Int = System.identityHashCode(executor)
 }
 
 // --- reusing these classes in other places ---

reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Scheduler.kt

@@ -32,6 +32,8 @@ open class SchedulerCoroutineDispatcher(private val scheduler: Scheduler) : Coro
     }
 
     override fun toString(): String = scheduler.toString()
+    override fun equals(other: Any?): Boolean = other is SchedulerCoroutineDispatcher && other.scheduler === scheduler
+    override fun hashCode(): Int = System.identityHashCode(scheduler)
 }
 
 /**

reactive/kotlinx-coroutines-rx2/src/main/kotlin/kotlinx/coroutines/experimental/rx2/RxScheduler.kt

@@ -56,4 +56,6 @@ public class SchedulerCoroutineDispatcher(private val scheduler: Scheduler) : Co
     }
 
     override fun toString(): String = scheduler.toString()
+    override fun equals(other: Any?): Boolean = other is SchedulerCoroutineDispatcher && other.scheduler === scheduler
+    override fun hashCode(): Int = System.identityHashCode(scheduler)
 }

ui/kotlinx-coroutines-android/src/main/kotlin/kotlinx/coroutines/experimental/android/HandlerContext.kt

@@ -18,10 +18,7 @@ package kotlinx.coroutines.experimental.android
 
 import android.os.Handler
 import android.os.Looper
-import kotlinx.coroutines.experimental.CancellableContinuation
-import kotlinx.coroutines.experimental.CoroutineDispatcher
-import kotlinx.coroutines.experimental.Delay
-import kotlinx.coroutines.experimental.DisposableHandle
+import kotlinx.coroutines.experimental.*
 import java.util.concurrent.TimeUnit
 import kotlin.coroutines.experimental.CoroutineContext
 
@@ -64,4 +61,6 @@ public class HandlerContext(
     }
 
     override fun toString() = name ?: handler.toString()
+    override fun equals(other: Any?): Boolean = other is HandlerContext && other.handler === handler
+    override fun hashCode(): Int = System.identityHashCode(handler)
 }