binder: Refactor: move FdTrigger to its own file / class.
Also move interruptable*Fully functions to RpcTransport so that we no
longer need pending() and pollSocket().
This also allows us to hide send() / recv(); callers should use
interruptableWriteFully / interruptableReadFully instead, because
those repsect the shutdown trigger.
- Fix one place to use interruptableWriteFully() instead of send() when
sending header.
interruptable*Fully are marked as virtual functions because TLS will
need to poll with events dynamically adjusted. See follow-up CLs for
TLS implementation.
Test: TH
Bug: 190868302
Change-Id: I131eed3a637b3a30280b320966e466bbfac0fc45
diff --git a/libs/binder/FdTrigger.h b/libs/binder/FdTrigger.h
new file mode 100644
index 0000000..984e685
--- /dev/null
+++ b/libs/binder/FdTrigger.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <memory>
+
+#include <android-base/unique_fd.h>
+#include <utils/Errors.h>
+
+namespace android {
+
+/** This is not a pipe. */
+class FdTrigger {
+public:
+ /** Returns nullptr for error case */
+ static std::unique_ptr<FdTrigger> make();
+
+ /**
+ * Close the write end of the pipe so that the read end receives POLLHUP.
+ * Not threadsafe.
+ */
+ void trigger();
+
+ /**
+ * Whether this has been triggered.
+ */
+ bool isTriggered();
+
+ /**
+ * Poll for a read event.
+ *
+ * event - for pollfd
+ *
+ * Return:
+ * true - time to read!
+ * false - trigger happened
+ */
+ status_t triggerablePoll(base::borrowed_fd fd, int16_t event);
+
+private:
+ base::unique_fd mWrite;
+ base::unique_fd mRead;
+};
+} // namespace android