logd: create SimpleLogBuffer and implement ChattyLogBuffer in terms of it
Test: unit tests with SimpleLogBuffer
Change-Id: If6e29418645b5491df9b8aeef8f95bb786aeba93
diff --git a/logd/SimpleLogBuffer.h b/logd/SimpleLogBuffer.h
new file mode 100644
index 0000000..9a2d01a
--- /dev/null
+++ b/logd/SimpleLogBuffer.h
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#pragma once
+
+#include <atomic>
+#include <list>
+#include <mutex>
+
+#include "LogBuffer.h"
+#include "LogBufferElement.h"
+#include "LogReaderList.h"
+#include "LogStatistics.h"
+#include "LogTags.h"
+#include "rwlock.h"
+
+class SimpleLogBuffer : public LogBuffer {
+ public:
+ SimpleLogBuffer(LogReaderList* reader_list, LogTags* tags, LogStatistics* stats);
+ ~SimpleLogBuffer();
+ void Init() override;
+
+ int Log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid, const char* msg,
+ uint16_t len) override;
+ uint64_t FlushTo(
+ LogWriter* writer, uint64_t start, pid_t* lastTid,
+ const std::function<FlushToResult(const LogBufferElement* element)>& filter) override;
+
+ bool Clear(log_id_t id, uid_t uid) override;
+ unsigned long GetSize(log_id_t id) override;
+ int SetSize(log_id_t id, unsigned long size) override;
+
+ uint64_t sequence() const override { return sequence_.load(std::memory_order_relaxed); }
+
+ protected:
+ virtual bool Prune(log_id_t id, unsigned long prune_rows, uid_t uid) REQUIRES(lock_);
+ virtual void LogInternal(LogBufferElement&& elem) REQUIRES(lock_);
+
+ // Returns an iterator to the oldest element for a given log type, or logs_.end() if
+ // there are no logs for the given log type. Requires logs_lock_ to be held.
+ std::list<LogBufferElement>::iterator GetOldest(log_id_t log_id) REQUIRES(lock_);
+ std::list<LogBufferElement>::iterator Erase(std::list<LogBufferElement>::iterator it)
+ REQUIRES(lock_);
+ void KickReader(LogReaderThread* reader, log_id_t id, unsigned long prune_rows)
+ REQUIRES_SHARED(lock_);
+
+ LogStatistics* stats() { return stats_; }
+ LogReaderList* reader_list() { return reader_list_; }
+ unsigned long max_size(log_id_t id) REQUIRES_SHARED(lock_) { return max_size_[id]; }
+ std::list<LogBufferElement>& logs() { return logs_; }
+
+ RwLock lock_;
+
+ private:
+ bool ShouldLog(log_id_t log_id, const char* msg, uint16_t len);
+ void MaybePrune(log_id_t id) REQUIRES(lock_);
+
+ LogReaderList* reader_list_;
+ LogTags* tags_;
+ LogStatistics* stats_;
+
+ std::atomic<uint64_t> sequence_ = 1;
+
+ unsigned long max_size_[LOG_ID_MAX] GUARDED_BY(lock_);
+ std::list<LogBufferElement> logs_ GUARDED_BY(lock_);
+ // Keeps track of the iterator to the oldest log message of a given log type, as an
+ // optimization when pruning logs. Use GetOldest() to retrieve.
+ std::optional<std::list<LogBufferElement>::iterator> oldest_[LOG_ID_MAX] GUARDED_BY(lock_);
+};