[Lldb-commits] [PATCH] D128026: [lldb] Add a BufferedLogHandler

[Jonas Devlieghere via Phabricator via lldb-commits]

JDevlieghere updated this revision to Diff 437788.
JDevlieghere added a comment.

Flush on destruction


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D128026/new/

https://reviews.llvm.org/D128026

Files:
  lldb/include/lldb/Utility/Log.h
  lldb/source/Utility/Log.cpp
  lldb/unittests/Utility/LogTest.cpp


Index: lldb/unittests/Utility/LogTest.cpp
===================================================================
--- lldb/unittests/Utility/LogTest.cpp
+++ lldb/unittests/Utility/LogTest.cpp
@@ -193,6 +193,34 @@
   EXPECT_EQ(GetDumpAsString(handler), "bazquxquux");
 }
 
+TEST(LogHandlerTest, BufferedLogHandler) {
+  auto delegate_sp = std::make_shared<TestLogHandler>();
+
+  {
+    BufferedLogHandler handler(3, delegate_sp);
+
+    handler.Emit("1");
+    handler.Emit("2");
+    EXPECT_EQ(delegate_sp->m_stream.str(), "");
+
+    handler.Emit("3");
+    EXPECT_EQ(delegate_sp->m_stream.str(), "123");
+
+    handler.Emit("4");
+    handler.Emit("5");
+    EXPECT_EQ(delegate_sp->m_stream.str(), "123");
+
+    handler.Emit("6");
+    EXPECT_EQ(delegate_sp->m_stream.str(), "123456");
+
+    handler.Emit("7");
+    EXPECT_EQ(delegate_sp->m_stream.str(), "123456");
+  }
+
+  // Make sure we flush on destruction.
+  EXPECT_EQ(delegate_sp->m_stream.str(), "1234567");
+}
+
 TEST_F(LogChannelTest, Enable) {
   EXPECT_EQ(nullptr, GetLog(TestChannel::FOO));
   std::string message;
Index: lldb/source/Utility/Log.cpp
===================================================================
--- lldb/source/Utility/Log.cpp
+++ lldb/source/Utility/Log.cpp
@@ -355,6 +355,27 @@
   m_callback(message.data(), m_baton);
 }
 
+BufferedLogHandler::BufferedLogHandler(size_t size,
+                                       std::shared_ptr<LogHandler> delegate)
+    : m_delegate(delegate), m_messages(std::make_unique<std::string[]>(size)),
+      m_size(size) {}
+
+BufferedLogHandler::~BufferedLogHandler() { Flush(); }
+
+void BufferedLogHandler::Emit(llvm::StringRef message) {
+  m_messages[m_next_index++] = message.str();
+  if (m_next_index == m_size)
+    Flush();
+}
+
+void BufferedLogHandler::Flush() {
+  for (size_t i = 0; i < m_next_index; ++i) {
+    m_delegate->Emit(m_messages[i]);
+    m_messages[i].clear();
+  }
+  m_next_index = 0;
+}
+
 RotatingLogHandler::RotatingLogHandler(size_t size)
     : m_messages(std::make_unique<std::string[]>(size)), m_size(size) {}
 
Index: lldb/include/lldb/Utility/Log.h
===================================================================
--- lldb/include/lldb/Utility/Log.h
+++ lldb/include/lldb/Utility/Log.h
@@ -77,6 +77,21 @@
   void *m_baton;
 };
 
+class BufferedLogHandler : public LogHandler {
+public:
+  BufferedLogHandler(size_t size, std::shared_ptr<LogHandler> delegate);
+  ~BufferedLogHandler();
+
+  void Emit(llvm::StringRef message) override;
+  void Flush();
+
+private:
+  std::shared_ptr<LogHandler> m_delegate;
+  std::unique_ptr<std::string[]> m_messages;
+  const size_t m_size = 0;
+  size_t m_next_index = 0;
+};
+
 class RotatingLogHandler : public LogHandler {
 public:
   RotatingLogHandler(size_t size);


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