Cache Events (#6015)

Provide EventListener methods to understand the impact of caching.

okhttp-testing-support/src/main/kotlin/okhttp3/CallEvent.kt

@@ -204,4 +204,24 @@ sealed class CallEvent {
     override val call: Call,
     val ioe: IOException
   ) : CallEvent()
+
+  data class SatisfactionFailure(
+    override val timestampNs: Long,
+    override val call: Call
+  ) : CallEvent()
+
+  data class CacheHit(
+    override val timestampNs: Long,
+    override val call: Call
+  ) : CallEvent()
+
+  data class CacheMiss(
+    override val timestampNs: Long,
+    override val call: Call
+  ) : CallEvent()
+
+  data class CacheConditionalHit(
+    override val timestampNs: Long,
+    override val call: Call
+  ) : CallEvent()
 }

okhttp-testing-support/src/main/kotlin/okhttp3/ClientRuleEventListener.kt

@@ -241,6 +241,30 @@ class ClientRuleEventListener(
     delegate.canceled(call)
   }
 
+  override fun satisfactionFailure(call: Call, response: Response) {
+    logWithTime("satisfactionFailure")
+
+    delegate.satisfactionFailure(call, response)
+  }
+
+  override fun cacheMiss(call: Call) {
+    logWithTime("cacheMiss")
+
+    delegate.cacheMiss(call)
+  }
+
+  override fun cacheHit(call: Call, response: Response) {
+    logWithTime("cacheHit")
+
+    delegate.cacheHit(call, response)
+  }
+
+  override fun cacheConditionalHit(call: Call, cachedResponse: Response) {
+    logWithTime("cacheConditionalHit")
+
+    delegate.cacheConditionalHit(call, cachedResponse)
+  }
+
   private fun logWithTime(message: String) {
     val timeMs = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNs)
     logger.invoke("[$timeMs ms] $message")

okhttp-testing-support/src/main/kotlin/okhttp3/RecordingEventListener.kt

@@ -22,6 +22,9 @@ import java.net.Proxy
 import java.util.Deque
 import java.util.concurrent.ConcurrentLinkedDeque
 import java.util.concurrent.TimeUnit
+import okhttp3.CallEvent.CacheConditionalHit
+import okhttp3.CallEvent.CacheHit
+import okhttp3.CallEvent.CacheMiss
 import okhttp3.CallEvent.CallEnd
 import okhttp3.CallEvent.CallFailed
 import okhttp3.CallEvent.CallStart
@@ -45,6 +48,7 @@ import okhttp3.CallEvent.ResponseBodyStart
 import okhttp3.CallEvent.ResponseFailed
 import okhttp3.CallEvent.ResponseHeadersEnd
 import okhttp3.CallEvent.ResponseHeadersStart
+import okhttp3.CallEvent.SatisfactionFailure
 import okhttp3.CallEvent.SecureConnectEnd
 import okhttp3.CallEvent.SecureConnectStart
 import org.assertj.core.api.Assertions.assertThat
@@ -260,4 +264,21 @@ open class RecordingEventListener : EventListener() {
   override fun canceled(
     call: Call
   ) = logEvent(Canceled(System.nanoTime(), call))
+
+  override fun satisfactionFailure(
+    call: Call,
+    response: Response
+  ) = logEvent(SatisfactionFailure(System.nanoTime(), call))
+
+  override fun cacheMiss(
+    call: Call
+  ) = logEvent(CacheMiss(System.nanoTime(), call))
+
+  override fun cacheHit(
+    call: Call,
+    response: Response
+  ) = logEvent(CacheHit(System.nanoTime(), call))
+
+  override fun cacheConditionalHit(call: Call, cachedResponse: Response) =
+    logEvent(CacheConditionalHit(System.nanoTime(), call))
 }