Save recent Widevine CDM logs

Bug: 162255728
Test: cdm unit tests
Change-Id: Ibc0daf374bedd8ac2a9a0515835e2775045962a7

libwvdrmengine/cdm/util/include/log.h

@@ -7,6 +7,11 @@
 #ifndef WVCDM_UTIL_LOG_H_
 #define WVCDM_UTIL_LOG_H_
 
+#include <cstdint>
+#include <deque>
+#include <mutex>
+#include <string>
+#include <vector>
 #include "util_common.h"
 
 namespace wvcdm {
@@ -27,6 +32,24 @@ typedef enum {
 
 extern LogPriority g_cutoff;
 
+struct LogMessage {
+  int64_t time_ms_;
+  LogPriority priority_;
+  std::string message_;
+};
+
+class LogBuffer {
+ public:
+  static const int MAX_CAPACITY = 100;
+  void addLog(const LogMessage& log);
+  std::vector<LogMessage> getLogs();
+ private:
+  std::deque<LogMessage> buffer_;
+  std::mutex mutex_;
+};
+
+extern LogBuffer g_logbuf;
+
 // Enable/disable verbose logging (LOGV).
 // This function is supplied for cases where the system layer does not
 // initialize logging.  This is also needed to initialize logging in

libwvdrmengine/cdm/util/src/log.cpp

@@ -26,7 +26,9 @@
 
 #include <stdarg.h>
 #include <stdio.h>
+#include <sys/time.h>
 
+#include <mutex>
 #include <string>
 
 /*
@@ -38,8 +40,20 @@
 
 namespace wvcdm {
 
+namespace {
+int64_t GetCurrentTimeMs() {
+    struct timeval tv{};
+    gettimeofday(&tv, NULL);
+    auto msec1 = static_cast<int64_t>(tv.tv_sec) * 1000;
+    auto msec2 = static_cast<int64_t>(tv.tv_usec) / 1000;
+    return msec1 + msec2;
+}
+}
+
 LogPriority g_cutoff = LOG_VERBOSE;
 
+LogBuffer g_logbuf;
+
 void InitLogging() {}
 
 void Log(const char* file, const char* function, int line, LogPriority level,
@@ -86,6 +100,22 @@ void Log(const char* file, const char* function, int line, LogPriority level,
   }
 
   __android_log_write(prio, LOG_TAG, buf);
+  if (level <= LOG_INFO) {
+    g_logbuf.addLog({GetCurrentTimeMs(), level, buf});
+  }
+}
+
+void LogBuffer::addLog(const LogMessage& log) {
+  std::unique_lock<std::mutex> lock(mutex_);
+  buffer_.push_back(log);
+  while (buffer_.size() > MAX_CAPACITY) {
+    buffer_.pop_front();
+  }
+}
+
+std::vector<LogMessage> LogBuffer::getLogs() {
+  std::unique_lock<std::mutex> lock(mutex_);
+  return {buffer_.begin(), buffer_.end()};
 }
 
 }  // namespace wvcdm