Use LOG_TAG instead of binary name as a tag.

If LOG_TAG was not defined, falling back to a default
behaviour (using binary name).

Bug: 35361699
Test: manual
Change-Id: I209a6ebaf0df882f98642f6d1831766cb296c951
diff --git a/base/logging.cpp b/base/logging.cpp
index 75078e5..0f2012a 100644
--- a/base/logging.cpp
+++ b/base/logging.cpp
@@ -187,8 +187,8 @@
 }
 #endif
 
-void StderrLogger(LogId, LogSeverity severity, const char*, const char* file,
-                  unsigned int line, const char* message) {
+void StderrLogger(LogId, LogSeverity severity, const char* tag, const char* file, unsigned int line,
+                  const char* message) {
   struct tm now;
   time_t t = time(nullptr);
 
@@ -205,8 +205,8 @@
   static_assert(arraysize(log_characters) - 1 == FATAL + 1,
                 "Mismatch in size of log_characters and values in LogSeverity");
   char severity_char = log_characters[severity];
-  fprintf(stderr, "%s %c %s %5d %5d %s:%u] %s\n", ProgramInvocationName().c_str(),
-          severity_char, timestamp, getpid(), GetThreadId(), file, line, message);
+  fprintf(stderr, "%s %c %s %5d %5d %s:%u] %s\n", tag ? tag : "nullptr", severity_char, timestamp,
+          getpid(), GetThreadId(), file, line, message);
 }
 
 void DefaultAborter(const char* abort_message) {
@@ -344,14 +344,14 @@
 // checks/logging in a function.
 class LogMessageData {
  public:
-  LogMessageData(const char* file, unsigned int line, LogId id,
-                 LogSeverity severity, int error)
+  LogMessageData(const char* file, unsigned int line, LogId id, LogSeverity severity,
+                 const char* tag, int error)
       : file_(GetFileBasename(file)),
         line_number_(line),
         id_(id),
         severity_(severity),
-        error_(error) {
-  }
+        tag_(tag),
+        error_(error) {}
 
   const char* GetFile() const {
     return file_;
@@ -365,6 +365,8 @@
     return severity_;
   }
 
+  const char* GetTag() const { return tag_; }
+
   LogId GetId() const {
     return id_;
   }
@@ -387,15 +389,19 @@
   const unsigned int line_number_;
   const LogId id_;
   const LogSeverity severity_;
+  const char* const tag_;
   const int error_;
 
   DISALLOW_COPY_AND_ASSIGN(LogMessageData);
 };
 
-LogMessage::LogMessage(const char* file, unsigned int line, LogId id,
-                       LogSeverity severity, int error)
-    : data_(new LogMessageData(file, line, id, severity, error)) {
-}
+LogMessage::LogMessage(const char* file, unsigned int line, LogId id, LogSeverity severity,
+                       const char* tag, int error)
+    : data_(new LogMessageData(file, line, id, severity, tag, error)) {}
+
+LogMessage::LogMessage(const char* file, unsigned int line, LogId id, LogSeverity severity,
+                       int error)
+    : LogMessage(file, line, id, severity, nullptr, error) {}
 
 LogMessage::~LogMessage() {
   // Check severity again. This is duplicate work wrt/ LOG macros, but not LOG_STREAM.
@@ -413,16 +419,16 @@
     // Do the actual logging with the lock held.
     std::lock_guard<std::mutex> lock(LoggingLock());
     if (msg.find('\n') == std::string::npos) {
-      LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetId(),
-              data_->GetSeverity(), msg.c_str());
+      LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetId(), data_->GetSeverity(),
+              data_->GetTag(), msg.c_str());
     } else {
       msg += '\n';
       size_t i = 0;
       while (i < msg.size()) {
         size_t nl = msg.find('\n', i);
         msg[nl] = '\0';
-        LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetId(),
-                data_->GetSeverity(), &msg[i]);
+        LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetId(), data_->GetSeverity(),
+                data_->GetTag(), &msg[i]);
         // Undo the zero-termination so we can give the complete message to the aborter.
         msg[nl] = '\n';
         i = nl + 1;
@@ -440,12 +446,17 @@
   return data_->GetBuffer();
 }
 
-void LogMessage::LogLine(const char* file, unsigned int line, LogId id,
-                         LogSeverity severity, const char* message) {
-  const char* tag = ProgramInvocationName().c_str();
+void LogMessage::LogLine(const char* file, unsigned int line, LogId id, LogSeverity severity,
+                         const char* tag, const char* message) {
+  if (tag == nullptr) tag = ProgramInvocationName().c_str();
   Logger()(id, severity, tag, file, line, message);
 }
 
+void LogMessage::LogLine(const char* file, unsigned int line, LogId id, LogSeverity severity,
+                         const char* message) {
+  LogLine(file, line, id, severity, nullptr, message);
+}
+
 LogSeverity GetMinimumLogSeverity() {
     return gMinimumLogSeverity;
 }