logd: add a test for clearing logs with a reader present

Test that:
1) Logs are cleared
2) More logs can be added after clear
3) Well behaving blocking readers stay connected and can read new logs
after clear.

Test: this unit test
Change-Id: I8497896f5fb068b1e50ff0dcaab1cf79aebae2bb

1 files changed, 95 insertions, 3 deletions

diff --git a/logd/LogBufferTest.cpp b/logd/LogBufferTest.cpp
index e651b4fec..412b6f1d7 100644
--- a/logd/LogBufferTest.cpp
+++ b/logd/LogBufferTest.cpp
@@ -26,6 +26,7 @@
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 
+#include "LogBuffer.h"
 #include "LogReaderThread.h"
 #include "LogWriter.h"
 
@@ -240,7 +241,7 @@ TEST_P(LogBufferTest, smoke_with_reader_thread) {
         std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
         std::unique_ptr<LogReaderThread> log_reader(
                 new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
-                                    0, ~0, 0, {}, 1, {}));
+                                    0, kLogMaskAll, 0, {}, 1, {}));
         reader_list_.reader_threads().emplace_back(std::move(log_reader));
     }
 
@@ -314,7 +315,7 @@ TEST_P(LogBufferTest, random_messages) {
         std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
         std::unique_ptr<LogReaderThread> log_reader(
                 new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
-                                    0, ~0, 0, {}, 1, {}));
+                                    0, kLogMaskAll, 0, {}, 1, {}));
         reader_list_.reader_threads().emplace_back(std::move(log_reader));
     }
 
@@ -348,7 +349,7 @@ TEST_P(LogBufferTest, read_last_sequence) {
         std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
         std::unique_ptr<LogReaderThread> log_reader(
                 new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
-                                    0, ~0, 0, {}, 3, {}));
+                                    0, kLogMaskAll, 0, {}, 3, {}));
         reader_list_.reader_threads().emplace_back(std::move(log_reader));
     }
 
@@ -363,4 +364,95 @@ TEST_P(LogBufferTest, read_last_sequence) {
     CompareLogMessages(expected_log_messages, read_log_messages);
 }
 
+TEST_P(LogBufferTest, clear_logs) {
+    // Log 3 initial logs.
+    std::vector<LogMessage> log_messages = {
+            {{.pid = 1, .tid = 2, .sec = 10000, .nsec = 20001, .lid = LOG_ID_MAIN, .uid = 0},
+             "first"},
+            {{.pid = 10, .tid = 2, .sec = 10000, .nsec = 20002, .lid = LOG_ID_MAIN, .uid = 0},
+             "second"},
+            {{.pid = 100, .tid = 2, .sec = 10000, .nsec = 20003, .lid = LOG_ID_MAIN, .uid = 0},
+             "third"},
+    };
+    FixupMessages(&log_messages);
+    LogMessages(log_messages);
+
+    std::vector<LogMessage> read_log_messages;
+    bool released = false;
+
+    // Connect a blocking reader.
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
+        std::unique_ptr<LogReaderThread> log_reader(
+                new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), false,
+                                    0, kLogMaskAll, 0, {}, 1, {}));
+        reader_list_.reader_threads().emplace_back(std::move(log_reader));
+    }
+
+    // Wait up to 250ms for the reader to read the first 3 logs.
+    constexpr int kMaxRetryCount = 50;
+    int count = 0;
+    for (; count < kMaxRetryCount; ++count) {
+        usleep(5000);
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        if (reader_list_.reader_threads().back()->start() == 4) {
+            break;
+        }
+    }
+    ASSERT_LT(count, kMaxRetryCount);
+
+    // Clear the log buffer.
+    log_buffer_->Clear(LOG_ID_MAIN, 0);
+
+    // Log 3 more logs.
+    std::vector<LogMessage> after_clear_messages = {
+            {{.pid = 1, .tid = 2, .sec = 10000, .nsec = 20001, .lid = LOG_ID_MAIN, .uid = 0},
+             "4th"},
+            {{.pid = 10, .tid = 2, .sec = 10000, .nsec = 20002, .lid = LOG_ID_MAIN, .uid = 0},
+             "5th"},
+            {{.pid = 100, .tid = 2, .sec = 10000, .nsec = 20003, .lid = LOG_ID_MAIN, .uid = 0},
+             "6th"},
+    };
+    FixupMessages(&after_clear_messages);
+    LogMessages(after_clear_messages);
+
+    // Wait up to 250ms for the reader to read the 3 additional logs.
+    for (count = 0; count < kMaxRetryCount; ++count) {
+        usleep(5000);
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        if (reader_list_.reader_threads().back()->start() == 7) {
+            break;
+        }
+    }
+    ASSERT_LT(count, kMaxRetryCount);
+
+    // Release the reader, wait for it to get the signal then check that it has been deleted.
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        reader_list_.reader_threads().back()->release_Locked();
+    }
+    while (!released) {
+        usleep(5000);
+    }
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        EXPECT_EQ(0U, reader_list_.reader_threads().size());
+    }
+
+    // Check that we have read all 6 messages.
+    std::vector<LogMessage> expected_log_messages = log_messages;
+    expected_log_messages.insert(expected_log_messages.end(), after_clear_messages.begin(),
+                                 after_clear_messages.end());
+    CompareLogMessages(expected_log_messages, read_log_messages);
+
+    // Finally, call FlushTo and ensure that only the 3 logs after the clear remain in the buffer.
+    std::vector<LogMessage> read_log_messages_after_clear;
+    std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages_after_clear, nullptr));
+    std::unique_ptr<FlushToState> flush_to_state = log_buffer_->CreateFlushToState(1, kLogMaskAll);
+    EXPECT_TRUE(log_buffer_->FlushTo(test_writer.get(), *flush_to_state, nullptr));
+    EXPECT_EQ(7ULL, flush_to_state->start());
+    CompareLogMessages(after_clear_messages, read_log_messages_after_clear);
+}
+
 INSTANTIATE_TEST_CASE_P(LogBufferTests, LogBufferTest, testing::Values("chatty", "simple"));