drm_hwcomposer: Add Worker class to abstract thread nasties

This will allow us to spin up threads more easily.

Change-Id: I74add3d20ab14a61f3c646877a3ee17d0bd99ac4
Signed-off-by: Sean Paul <seanpaul@chromium.org>

3 files changed, 257 insertions, 1 deletions

diff --git a/Android.mk b/Android.mk
index 0b8f1ad..58bf1ef 100644
--- a/Android.mk
+++ b/Android.mk
@@ -44,7 +44,8 @@ LOCAL_SRC_FILES := \
 	drmmode.cpp \
 	drmplane.cpp \
 	drmproperty.cpp \
-	hwcomposer.cpp
+	hwcomposer.cpp \
+	worker.cpp
 
 ifeq ($(strip $(BUFFER_IMPORTER)),drm-gralloc)
 LOCAL_C_INCLUDES += external/drm_gralloc
diff --git a/worker.cpp b/worker.cpp
new file mode 100644
index 0000000..e169911
--- /dev/null
+++ b/worker.cpp
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "hwc-drm-worker"
+
+#include "worker.h"
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <sys/resource.h>
+#include <sys/signal.h>
+
+#include <cutils/log.h>
+
+namespace android {
+
+Worker::Worker(const char *name, int priority)
+    : name_(name), priority_(priority), exit_(false), initialized_(false) {
+}
+
+Worker::~Worker() {
+  if (!initialized_)
+    return;
+
+  pthread_kill(thread_, SIGTERM);
+  pthread_cond_destroy(&cond_);
+  pthread_mutex_destroy(&lock_);
+}
+
+int Worker::InitWorker() {
+  int ret = pthread_cond_init(&cond_, NULL);
+  if (ret) {
+    ALOGE("Failed to int thread %s condition %d", name_.c_str(), ret);
+    return ret;
+  }
+
+  ret = pthread_mutex_init(&lock_, NULL);
+  if (ret) {
+    ALOGE("Failed to init thread %s lock %d", name_.c_str(), ret);
+    pthread_cond_destroy(&cond_);
+    return ret;
+  }
+
+  ret = pthread_create(&thread_, NULL, InternalRoutine, this);
+  if (ret) {
+    ALOGE("Could not create thread %s %d", name_.c_str(), ret);
+    pthread_mutex_destroy(&lock_);
+    pthread_cond_destroy(&cond_);
+    return ret;
+  }
+  initialized_ = true;
+  return 0;
+}
+
+bool Worker::initialized() const {
+  return initialized_;
+}
+
+int Worker::Lock() {
+  return pthread_mutex_lock(&lock_);
+}
+
+int Worker::Unlock() {
+  return pthread_mutex_unlock(&lock_);
+}
+
+int Worker::SignalLocked() {
+  return SignalThreadLocked(false);
+}
+
+int Worker::ExitLocked() {
+  int signal_ret = SignalThreadLocked(true);
+  if (signal_ret)
+    ALOGE("Failed to signal thread %s with exit %d", name_.c_str(), signal_ret);
+
+  int join_ret = pthread_join(thread_, NULL);
+  if (join_ret && join_ret != ESRCH)
+    ALOGE("Failed to join thread %s in exit %d", name_.c_str(), join_ret);
+
+  return signal_ret | join_ret;
+}
+
+int Worker::Signal() {
+  int ret = Lock();
+  if (ret) {
+    ALOGE("Failed to acquire lock in Signal() %d\n", ret);
+    return ret;
+  }
+
+  int signal_ret = SignalLocked();
+
+  ret = Unlock();
+  if (ret) {
+    ALOGE("Failed to release lock in Signal() %d\n", ret);
+    return ret;
+  }
+  return signal_ret;
+}
+
+int Worker::Exit() {
+  int ret = Lock();
+  if (ret) {
+    ALOGE("Failed to acquire lock in Exit() %d\n", ret);
+    return ret;
+  }
+
+  int exit_ret = ExitLocked();
+
+  ret = Unlock();
+  if (ret) {
+    ALOGE("Failed to release lock in Exit() %d\n", ret);
+    return ret;
+  }
+  return exit_ret;
+}
+
+int Worker::WaitForSignalOrExitLocked() {
+  if (exit_)
+    return -EINTR;
+
+  int ret = pthread_cond_wait(&cond_, &lock_);
+
+  if (exit_)
+    return -EINTR;
+
+  return ret;
+}
+
+// static
+void *Worker::InternalRoutine(void *arg) {
+  Worker *worker = (Worker *)arg;
+
+  setpriority(PRIO_PROCESS, 0, worker->priority_);
+
+  while (true) {
+    int ret = worker->Lock();
+    if (ret) {
+      ALOGE("Failed to lock %s thread %d", worker->name_.c_str(), ret);
+      continue;
+    }
+
+    bool exit = worker->exit_;
+
+    ret = worker->Unlock();
+    if (ret) {
+      ALOGE("Failed to unlock %s thread %d", worker->name_.c_str(), ret);
+      break;
+    }
+    if (exit)
+      break;
+
+    worker->Routine();
+  }
+  return NULL;
+}
+
+int Worker::SignalThreadLocked(bool exit) {
+  if (exit)
+    exit_ = exit;
+
+  int ret = pthread_cond_signal(&cond_);
+  if (ret) {
+    ALOGE("Failed to signal condition on %s thread %d", name_.c_str(), ret);
+    return ret;
+  }
+
+  return 0;
+}
+}
diff --git a/worker.h b/worker.h
new file mode 100644
index 0000000..492693c
--- /dev/null
+++ b/worker.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef ANDROID_WORKER_H_
+#define ANDROID_WORKER_H_
+
+#include <pthread.h>
+#include <string>
+
+namespace android {
+
+class Worker {
+ public:
+  int Lock();
+  int Unlock();
+
+  // Must be called with the lock acquired
+  int SignalLocked();
+  int ExitLocked();
+
+  // Convenience versions of above, acquires the lock
+  int Signal();
+  int Exit();
+
+ protected:
+  Worker(const char *name, int priority);
+  virtual ~Worker();
+
+  int InitWorker();
+
+  bool initialized() const;
+
+  virtual void Routine() = 0;
+
+  /*
+   * Must be called with the lock acquired.
+   * Returns -EINTR if interrupted by exit request
+   */
+  int WaitForSignalOrExitLocked();
+
+ private:
+  static void *InternalRoutine(void *worker);
+
+  // Must be called with the lock acquired
+  int SignalThreadLocked(bool exit);
+
+  std::string name_;
+  int priority_;
+
+  pthread_t thread_;
+  pthread_mutex_t lock_;
+  pthread_cond_t cond_;
+
+  bool exit_;
+  bool initialized_;
+};
+}
+
+#endif