Merge "Add google3 style logging to libbase."

9 files changed, 864 insertions, 24 deletions

diff --git a/base/Android.mk b/base/Android.mk
index 17d6ece..162c6cb 100644
--- a/base/Android.mk
+++ b/base/Android.mk
@@ -18,13 +18,17 @@ LOCAL_PATH := $(call my-dir)
 
 libbase_src_files := \
     file.cpp \
+    logging.cpp \
     stringprintf.cpp \
     strings.cpp \
 
 libbase_test_src_files := \
     file_test.cpp \
+    logging_test.cpp \
     stringprintf_test.cpp \
     strings_test.cpp \
+    test_main.cpp \
+    test_utils.cpp \
 
 libbase_cppflags := \
     -Wall \
@@ -77,6 +81,7 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := libbase_test
 LOCAL_CLANG := true
 LOCAL_SRC_FILES := $(libbase_test_src_files)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)
 LOCAL_CPPFLAGS := $(libbase_cppflags)
 LOCAL_SHARED_LIBRARIES := libbase
 LOCAL_MULTILIB := both
@@ -87,6 +92,7 @@ include $(BUILD_NATIVE_TEST)
 include $(CLEAR_VARS)
 LOCAL_MODULE := libbase_test
 LOCAL_SRC_FILES := $(libbase_test_src_files)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)
 LOCAL_CPPFLAGS := $(libbase_cppflags)
 LOCAL_SHARED_LIBRARIES := libbase
 LOCAL_MULTILIB := both
diff --git a/base/CPPLINT.cfg b/base/CPPLINT.cfg
index 5ee068e..a61c08d 100644
--- a/base/CPPLINT.cfg
+++ b/base/CPPLINT.cfg
@@ -1,2 +1,2 @@
 set noparent
-filter=-build/header_guard
+filter=-build/header_guard,-build/include,-build/c++11
diff --git a/base/file_test.cpp b/base/file_test.cpp
index 34b8755..fc48b32 100644
--- a/base/file_test.cpp
+++ b/base/file_test.cpp
@@ -24,29 +24,7 @@
 
 #include <string>
 
-class TemporaryFile {
- public:
-  TemporaryFile() {
-    init("/data/local/tmp");
-    if (fd == -1) {
-      init("/tmp");
-    }
-  }
-
-  ~TemporaryFile() {
-    close(fd);
-    unlink(filename);
-  }
-
-  int fd;
-  char filename[1024];
-
- private:
-  void init(const char* tmp_dir) {
-    snprintf(filename, sizeof(filename), "%s/TemporaryFile-XXXXXX", tmp_dir);
-    fd = mkstemp(filename);
-  }
-};
+#include "test_utils.h"
 
 TEST(file, ReadFileToString_ENOENT) {
   std::string s("hello");
diff --git a/base/include/base/logging.h b/base/include/base/logging.h
new file mode 100644
index 0000000..5e115fe
--- /dev/null
+++ b/base/include/base/logging.h
@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef BASE_LOGGING_H
+#define BASE_LOGGING_H
+
+#include <memory>
+#include <ostream>
+
+#include "base/macros.h"
+
+namespace android {
+namespace base {
+
+enum LogSeverity {
+  VERBOSE,
+  DEBUG,
+  INFO,
+  WARNING,
+  ERROR,
+  FATAL,
+};
+
+// Configure logging based on ANDROID_LOG_TAGS environment variable.
+// We need to parse a string that looks like
+//
+//      *:v jdwp:d dalvikvm:d dalvikvm-gc:i dalvikvmi:i
+//
+// The tag (or '*' for the global level) comes first, followed by a colon and a
+// letter indicating the minimum priority level we're expected to log.  This can
+// be used to reveal or conceal logs with specific tags.
+extern void InitLogging(char* argv[]);
+
+// Returns the command line used to invoke the current tool or nullptr if
+// InitLogging hasn't been performed.
+extern const char* GetCmdLine();
+
+// The command used to start the program, such as "/system/bin/dalvikvm". If
+// InitLogging hasn't been performed then just returns "unknown"
+extern const char* ProgramInvocationName();
+
+// A short version of the command used to start the program, such as "dalvikvm".
+// If InitLogging hasn't been performed then just returns "unknown"
+extern const char* ProgramInvocationShortName();
+
+// Logs a message to logcat on Android otherwise to stderr. If the severity is
+// FATAL it also causes an abort. For example:
+//
+//     LOG(FATAL) << "We didn't expect to reach here";
+#define LOG(severity)                                                        \
+  ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::severity, \
+                              -1).stream()
+
+// A variant of LOG that also logs the current errno value. To be used when
+// library calls fail.
+#define PLOG(severity)                                                       \
+  ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::severity, \
+                              errno).stream()
+
+// Marker that code is yet to be implemented.
+#define UNIMPLEMENTED(level) \
+  LOG(level) << __PRETTY_FUNCTION__ << " unimplemented "
+
+// Check whether condition x holds and LOG(FATAL) if not. The value of the
+// expression x is only evaluated once. Extra logging can be appended using <<
+// after. For example:
+//
+//     CHECK(false == true) results in a log message of
+//       "Check failed: false == true".
+#define CHECK(x)                                                            \
+  if (UNLIKELY(!(x)))                                                       \
+    ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::FATAL, \
+                                -1).stream()                                \
+        << "Check failed: " #x << " "
+
+// Helper for CHECK_xx(x,y) macros.
+#define CHECK_OP(LHS, RHS, OP)                                                \
+  for (auto _values = ::android::base::MakeEagerEvaluator(LHS, RHS);          \
+       UNLIKELY(!(_values.lhs OP _values.rhs));                               \
+       /* empty */)                                                           \
+  ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::FATAL, -1) \
+          .stream()                                                           \
+      << "Check failed: " << #LHS << " " << #OP << " " << #RHS                \
+      << " (" #LHS "=" << _values.lhs << ", " #RHS "=" << _values.rhs << ") "
+
+// Check whether a condition holds between x and y, LOG(FATAL) if not. The value
+// of the expressions x and y is evaluated once. Extra logging can be appended
+// using << after. For example:
+//
+//     CHECK_NE(0 == 1, false) results in
+//       "Check failed: false != false (0==1=false, false=false) ".
+#define CHECK_EQ(x, y) CHECK_OP(x, y, == )
+#define CHECK_NE(x, y) CHECK_OP(x, y, != )
+#define CHECK_LE(x, y) CHECK_OP(x, y, <= )
+#define CHECK_LT(x, y) CHECK_OP(x, y, < )
+#define CHECK_GE(x, y) CHECK_OP(x, y, >= )
+#define CHECK_GT(x, y) CHECK_OP(x, y, > )
+
+// Helper for CHECK_STRxx(s1,s2) macros.
+#define CHECK_STROP(s1, s2, sense)                                         \
+  if (UNLIKELY((strcmp(s1, s2) == 0) != sense))                            \
+    LOG(FATAL) << "Check failed: "                                         \
+               << "\"" << s1 << "\""                                       \
+               << (sense ? " == " : " != ") << "\"" << s2 << "\""
+
+// Check for string (const char*) equality between s1 and s2, LOG(FATAL) if not.
+#define CHECK_STREQ(s1, s2) CHECK_STROP(s1, s2, true)
+#define CHECK_STRNE(s1, s2) CHECK_STROP(s1, s2, false)
+
+// Perform the pthread function call(args), LOG(FATAL) on error.
+#define CHECK_PTHREAD_CALL(call, args, what)                           \
+  do {                                                                 \
+    int rc = call args;                                                \
+    if (rc != 0) {                                                     \
+      errno = rc;                                                      \
+      PLOG(FATAL) << #call << " failed for " << what; \
+    }                                                                  \
+  } while (false)
+
+// CHECK that can be used in a constexpr function. For example:
+//
+//    constexpr int half(int n) {
+//      return
+//          DCHECK_CONSTEXPR(n >= 0, , 0)
+//          CHECK_CONSTEXPR((n & 1) == 0),
+//              << "Extra debugging output: n = " << n, 0)
+//          n / 2;
+//    }
+#define CHECK_CONSTEXPR(x, out, dummy)                                     \
+  (UNLIKELY(!(x)))                                                         \
+      ? (LOG(FATAL) << "Check failed: " << #x out, dummy) \
+      :
+
+// DCHECKs are debug variants of CHECKs only enabled in debug builds. Generally
+// CHECK should be used unless profiling identifies a CHECK as being in
+// performance critical code.
+#if defined(NDEBUG)
+static constexpr bool kEnableDChecks = false;
+#else
+static constexpr bool kEnableDChecks = true;
+#endif
+
+#define DCHECK(x) \
+  if (::android::base::kEnableDChecks) CHECK(x)
+#define DCHECK_EQ(x, y) \
+  if (::android::base::kEnableDChecks) CHECK_EQ(x, y)
+#define DCHECK_NE(x, y) \
+  if (::android::base::kEnableDChecks) CHECK_NE(x, y)
+#define DCHECK_LE(x, y) \
+  if (::android::base::kEnableDChecks) CHECK_LE(x, y)
+#define DCHECK_LT(x, y) \
+  if (::android::base::kEnableDChecks) CHECK_LT(x, y)
+#define DCHECK_GE(x, y) \
+  if (::android::base::kEnableDChecks) CHECK_GE(x, y)
+#define DCHECK_GT(x, y) \
+  if (::android::base::kEnableDChecks) CHECK_GT(x, y)
+#define DCHECK_STREQ(s1, s2) \
+  if (::android::base::kEnableDChecks) CHECK_STREQ(s1, s2)
+#define DCHECK_STRNE(s1, s2) \
+  if (::android::base::kEnableDChecks) CHECK_STRNE(s1, s2)
+#if defined(NDEBUG)
+#define DCHECK_CONSTEXPR(x, out, dummy)
+#else
+#define DCHECK_CONSTEXPR(x, out, dummy) CHECK_CONSTEXPR(x, out, dummy)
+#endif
+
+// Temporary class created to evaluate the LHS and RHS, used with
+// MakeEagerEvaluator to infer the types of LHS and RHS.
+template <typename LHS, typename RHS>
+struct EagerEvaluator {
+  EagerEvaluator(LHS l, RHS r) : lhs(l), rhs(r) {
+  }
+  LHS lhs;
+  RHS rhs;
+};
+
+// Helper function for CHECK_xx.
+template <typename LHS, typename RHS>
+static inline EagerEvaluator<LHS, RHS> MakeEagerEvaluator(LHS lhs, RHS rhs) {
+  return EagerEvaluator<LHS, RHS>(lhs, rhs);
+}
+
+// Explicitly instantiate EagerEvalue for pointers so that char*s aren't treated
+// as strings. To compare strings use CHECK_STREQ and CHECK_STRNE. We rely on
+// signed/unsigned warnings to protect you against combinations not explicitly
+// listed below.
+#define EAGER_PTR_EVALUATOR(T1, T2)               \
+  template <>                                     \
+  struct EagerEvaluator<T1, T2> {                 \
+    EagerEvaluator(T1 l, T2 r)                    \
+        : lhs(reinterpret_cast<const void*>(l)),  \
+          rhs(reinterpret_cast<const void*>(r)) { \
+    }                                             \
+    const void* lhs;                              \
+    const void* rhs;                              \
+  }
+EAGER_PTR_EVALUATOR(const char*, const char*);
+EAGER_PTR_EVALUATOR(const char*, char*);
+EAGER_PTR_EVALUATOR(char*, const char*);
+EAGER_PTR_EVALUATOR(char*, char*);
+EAGER_PTR_EVALUATOR(const unsigned char*, const unsigned char*);
+EAGER_PTR_EVALUATOR(const unsigned char*, unsigned char*);
+EAGER_PTR_EVALUATOR(unsigned char*, const unsigned char*);
+EAGER_PTR_EVALUATOR(unsigned char*, unsigned char*);
+EAGER_PTR_EVALUATOR(const signed char*, const signed char*);
+EAGER_PTR_EVALUATOR(const signed char*, signed char*);
+EAGER_PTR_EVALUATOR(signed char*, const signed char*);
+EAGER_PTR_EVALUATOR(signed char*, signed char*);
+
+// Data for the log message, not stored in LogMessage to avoid increasing the
+// stack size.
+class LogMessageData;
+
+// A LogMessage is a temporarily scoped object used by LOG and the unlikely part
+// of a CHECK. The destructor will abort if the severity is FATAL.
+class LogMessage {
+ public:
+  LogMessage(const char* file, unsigned int line, LogSeverity severity,
+             int error);
+
+  ~LogMessage();
+
+  // Returns the stream associated with the message, the LogMessage performs
+  // output when it goes out of scope.
+  std::ostream& stream();
+
+  // The routine that performs the actual logging.
+  static void LogLine(const char* file, unsigned int line, LogSeverity severity,
+                      const char* msg);
+
+  // A variant of the above for use with little stack.
+  static void LogLineLowStack(const char* file, unsigned int line,
+                              LogSeverity severity, const char* msg);
+
+ private:
+  const std::unique_ptr<LogMessageData> data_;
+
+  DISALLOW_COPY_AND_ASSIGN(LogMessage);
+};
+
+// Allows to temporarily change the minimum severity level for logging.
+class ScopedLogSeverity {
+ public:
+  explicit ScopedLogSeverity(LogSeverity level);
+  ~ScopedLogSeverity();
+
+ private:
+  LogSeverity old_;
+};
+
+}  // namespace base
+}  // namespace android
+
+#endif  // BASE_LOGGING_H
diff --git a/base/logging.cpp b/base/logging.cpp
new file mode 100644
index 0000000..3d6c0c2
--- /dev/null
+++ b/base/logging.cpp
@@ -0,0 +1,323 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include "base/logging.h"
+
+#include <iostream>
+#include <limits>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "base/strings.h"
+
+// Headers for LogMessage::LogLine.
+#ifdef __ANDROID__
+#include <android/set_abort_message.h>
+#include "cutils/log.h"
+#else
+#include <sys/types.h>
+#include <unistd.h>
+#endif
+
+// For GetTid.
+#if defined(__APPLE__)
+#include "AvailabilityMacros.h"  // For MAC_OS_X_VERSION_MAX_ALLOWED
+#include <sys/syscall.h>
+#include <sys/time.h>
+#elif !defined(__BIONIC__)
+#include <syscall.h>
+#endif
+
+namespace android {
+namespace base {
+
+static std::mutex logging_lock;
+
+static LogSeverity gMinimumLogSeverity = INFO;
+static std::unique_ptr<std::string> gCmdLine;
+static std::unique_ptr<std::string> gProgramInvocationName;
+static std::unique_ptr<std::string> gProgramInvocationShortName;
+
+#ifndef __ANDROID__
+static pid_t GetTid() {
+#if defined(__APPLE__)
+  uint64_t owner;
+  // Requires Mac OS 10.6
+  CHECK_PTHREAD_CALL(pthread_threadid_np, (NULL, &owner), __FUNCTION__);
+  return owner;
+#else
+  return syscall(__NR_gettid);
+#endif
+}
+#endif  // __ANDROID__
+
+const char* GetCmdLine() {
+  return (gCmdLine.get() != nullptr) ? gCmdLine->c_str() : nullptr;
+}
+
+const char* ProgramInvocationName() {
+  return (gProgramInvocationName.get() != nullptr)
+             ? gProgramInvocationName->c_str()
+             : "unknown";
+}
+
+const char* ProgramInvocationShortName() {
+  return (gProgramInvocationShortName.get() != nullptr)
+             ? gProgramInvocationShortName->c_str()
+             : "unknown";
+}
+
+void InitLogging(char* argv[]) {
+  if (gCmdLine.get() != nullptr) {
+    return;
+  }
+
+  // Stash the command line for later use. We can use /proc/self/cmdline on
+  // Linux to recover this, but we don't have that luxury on the Mac, and there
+  // are a couple of argv[0] variants that are commonly used.
+  if (argv != nullptr) {
+    gCmdLine.reset(new std::string(argv[0]));
+    for (size_t i = 1; argv[i] != nullptr; ++i) {
+      gCmdLine->append(" ");
+      gCmdLine->append(argv[i]);
+    }
+    gProgramInvocationName.reset(new std::string(argv[0]));
+    const char* last_slash = strrchr(argv[0], '/');
+    gProgramInvocationShortName.reset(
+        new std::string((last_slash != nullptr) ? last_slash + 1 : argv[0]));
+  } else {
+    // TODO: fall back to /proc/self/cmdline when argv is NULL on Linux.
+    gCmdLine.reset(new std::string("<unset>"));
+  }
+  const char* tags = getenv("ANDROID_LOG_TAGS");
+  if (tags == nullptr) {
+    return;
+  }
+
+  std::vector<std::string> specs;
+  Split(tags, ' ', &specs);
+  for (size_t i = 0; i < specs.size(); ++i) {
+    // "tag-pattern:[vdiwefs]"
+    std::string spec(specs[i]);
+    if (spec.size() == 3 && StartsWith(spec, "*:")) {
+      switch (spec[2]) {
+        case 'v':
+          gMinimumLogSeverity = VERBOSE;
+          continue;
+        case 'd':
+          gMinimumLogSeverity = DEBUG;
+          continue;
+        case 'i':
+          gMinimumLogSeverity = INFO;
+          continue;
+        case 'w':
+          gMinimumLogSeverity = WARNING;
+          continue;
+        case 'e':
+          gMinimumLogSeverity = ERROR;
+          continue;
+        case 'f':
+          gMinimumLogSeverity = FATAL;
+          continue;
+        // liblog will even suppress FATAL if you say 's' for silent, but that's
+        // crazy!
+        case 's':
+          gMinimumLogSeverity = FATAL;
+          continue;
+      }
+    }
+    LOG(FATAL) << "unsupported '" << spec << "' in ANDROID_LOG_TAGS (" << tags
+               << ")";
+  }
+}
+
+// This indirection greatly reduces the stack impact of having lots of
+// checks/logging in a function.
+class LogMessageData {
+ public:
+  LogMessageData(const char* file, unsigned int line, LogSeverity severity,
+                 int error)
+      : file_(file), line_number_(line), severity_(severity), error_(error) {
+    const char* last_slash = strrchr(file, '/');
+    file = (last_slash == nullptr) ? file : last_slash + 1;
+  }
+
+  const char* GetFile() const {
+    return file_;
+  }
+
+  unsigned int GetLineNumber() const {
+    return line_number_;
+  }
+
+  LogSeverity GetSeverity() const {
+    return severity_;
+  }
+
+  int GetError() const {
+    return error_;
+  }
+
+  std::ostream& GetBuffer() {
+    return buffer_;
+  }
+
+  std::string ToString() const {
+    return buffer_.str();
+  }
+
+ private:
+  std::ostringstream buffer_;
+  const char* const file_;
+  const unsigned int line_number_;
+  const LogSeverity severity_;
+  const int error_;
+
+  DISALLOW_COPY_AND_ASSIGN(LogMessageData);
+};
+
+LogMessage::LogMessage(const char* file, unsigned int line,
+                       LogSeverity severity, int error)
+    : data_(new LogMessageData(file, line, severity, error)) {
+}
+
+LogMessage::~LogMessage() {
+  if (data_->GetSeverity() < gMinimumLogSeverity) {
+    return;  // No need to format something we're not going to output.
+  }
+
+  // Finish constructing the message.
+  if (data_->GetError() != -1) {
+    data_->GetBuffer() << ": " << strerror(data_->GetError());
+  }
+  std::string msg(data_->ToString());
+
+  // Do the actual logging with the lock held.
+  {
+    std::lock_guard<std::mutex> lock(logging_lock);
+    if (msg.find('\n') == std::string::npos) {
+      LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetSeverity(),
+              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_->GetSeverity(),
+                &msg[i]);
+        i = nl + 1;
+      }
+    }
+  }
+
+  // Abort if necessary.
+  if (data_->GetSeverity() == FATAL) {
+#ifdef __ANDROID__
+    android_set_abort_message(msg.c_str());
+#endif
+    abort();
+  }
+}
+
+std::ostream& LogMessage::stream() {
+  return data_->GetBuffer();
+}
+
+#ifdef __ANDROID__
+static const android_LogPriority kLogSeverityToAndroidLogPriority[] = {
+    ANDROID_LOG_VERBOSE, ANDROID_LOG_DEBUG, ANDROID_LOG_INFO,
+    ANDROID_LOG_WARN,    ANDROID_LOG_ERROR, ANDROID_LOG_FATAL};
+static_assert(arraysize(kLogSeverityToAndroidLogPriority) == FATAL + 1,
+              "Mismatch in size of kLogSeverityToAndroidLogPriority and values "
+              "in LogSeverity");
+#endif
+
+void LogMessage::LogLine(const char* file, unsigned int line,
+                         LogSeverity log_severity, const char* message) {
+#ifdef __ANDROID__
+  const char* tag = ProgramInvocationShortName();
+  int priority = kLogSeverityToAndroidLogPriority[log_severity];
+  if (priority == ANDROID_LOG_FATAL) {
+    LOG_PRI(priority, tag, "%s:%u] %s", file, line, message);
+  } else {
+    LOG_PRI(priority, tag, "%s", message);
+  }
+#else
+  static const char* log_characters = "VDIWEF";
+  CHECK_EQ(strlen(log_characters), FATAL + 1U);
+  char severity = log_characters[log_severity];
+  fprintf(stderr, "%s %c %5d %5d %s:%u] %s\n", ProgramInvocationShortName(),
+          severity, getpid(), GetTid(), file, line, message);
+#endif
+}
+
+void LogMessage::LogLineLowStack(const char* file, unsigned int line,
+                                 LogSeverity log_severity, const char* message) {
+#ifdef __ANDROID__
+  // Use android_writeLog() to avoid stack-based buffers used by
+  // android_printLog().
+  const char* tag = ProgramInvocationShortName();
+  int priority = kLogSeverityToAndroidLogPriority[log_severity];
+  char* buf = nullptr;
+  size_t buf_size = 0u;
+  if (priority == ANDROID_LOG_FATAL) {
+    // Allocate buffer for snprintf(buf, buf_size, "%s:%u] %s", file, line,
+    // message) below.  If allocation fails, fall back to printing only the
+    // message.
+    buf_size = strlen(file) + 1 /* ':' */ +
+               std::numeric_limits<typeof(line)>::max_digits10 + 2 /* "] " */ +
+               strlen(message) + 1 /* terminating 0 */;
+    buf = reinterpret_cast<char*>(malloc(buf_size));
+  }
+  if (buf != nullptr) {
+    snprintf(buf, buf_size, "%s:%u] %s", file, line, message);
+    android_writeLog(priority, tag, buf);
+    free(buf);
+  } else {
+    android_writeLog(priority, tag, message);
+  }
+#else
+  static const char* log_characters = "VDIWEF";
+  CHECK_EQ(strlen(log_characters), FATAL + 1U);
+
+  const char* program_name = ProgramInvocationShortName();
+  write(STDERR_FILENO, program_name, strlen(program_name));
+  write(STDERR_FILENO, " ", 1);
+  write(STDERR_FILENO, &log_characters[log_severity], 1);
+  write(STDERR_FILENO, " ", 1);
+  // TODO: pid and tid.
+  write(STDERR_FILENO, file, strlen(file));
+  // TODO: line.
+  UNUSED(line);
+  write(STDERR_FILENO, "] ", 2);
+  write(STDERR_FILENO, message, strlen(message));
+  write(STDERR_FILENO, "\n", 1);
+#endif
+}
+
+ScopedLogSeverity::ScopedLogSeverity(LogSeverity level) {
+  old_ = gMinimumLogSeverity;
+  gMinimumLogSeverity = level;
+}
+
+ScopedLogSeverity::~ScopedLogSeverity() {
+  gMinimumLogSeverity = old_;
+}
+
+}  // namespace base
+}  // namespace android
diff --git a/base/logging_test.cpp b/base/logging_test.cpp
new file mode 100644
index 0000000..0a03e38
--- /dev/null
+++ b/base/logging_test.cpp
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include "base/logging.h"
+
+#include <regex>
+#include <string>
+
+#include "base/file.h"
+#include "base/stringprintf.h"
+#include "test_utils.h"
+
+#include <gtest/gtest.h>
+
+#ifdef __ANDROID__
+#define HOST_TEST(suite, name) TEST(suite, DISABLED_ ## name)
+#else
+#define HOST_TEST(suite, name) TEST(suite, name)
+#endif
+
+class CapturedStderr {
+ public:
+  CapturedStderr() : old_stderr_(-1) {
+    init();
+  }
+
+  ~CapturedStderr() {
+    reset();
+  }
+
+  int fd() const {
+    return temp_file_.fd;
+  }
+
+ private:
+  void init() {
+    old_stderr_ = dup(STDERR_FILENO);
+    ASSERT_NE(-1, old_stderr_);
+    ASSERT_NE(-1, dup2(fd(), STDERR_FILENO));
+  }
+
+  void reset() {
+    ASSERT_NE(-1, dup2(old_stderr_, STDERR_FILENO));
+    ASSERT_EQ(0, close(old_stderr_));
+  }
+
+  TemporaryFile temp_file_;
+  int old_stderr_;
+};
+
+HOST_TEST(logging, CHECK) {
+  ASSERT_DEATH(CHECK(false), "Check failed: false ");
+  CHECK(true);
+
+  ASSERT_DEATH(CHECK_EQ(0, 1), "Check failed: 0 == 1 ");
+  CHECK_EQ(0, 0);
+
+  ASSERT_DEATH(CHECK_STREQ("foo", "bar"), R"(Check failed: "foo" == "bar")");
+  CHECK_STREQ("foo", "foo");
+}
+
+std::string make_log_pattern(android::base::LogSeverity severity,
+                             const char* message) {
+  static const char* log_characters = "VDIWEF";
+  char log_char = log_characters[severity];
+  return android::base::StringPrintf(
+      "%c[[:space:]]+[[:digit:]]+[[:space:]]+[[:digit:]]+ " __FILE__
+      ":[[:digit:]]+] %s",
+      log_char, message);
+}
+
+HOST_TEST(logging, LOG) {
+  ASSERT_DEATH(LOG(FATAL) << "foobar", "foobar");
+
+  {
+    CapturedStderr cap;
+    LOG(WARNING) << "foobar";
+    ASSERT_EQ(0, lseek(cap.fd(), SEEK_SET, 0));
+
+    std::string output;
+    android::base::ReadFdToString(cap.fd(), &output);
+
+    std::regex message_regex(
+        make_log_pattern(android::base::WARNING, "foobar"));
+    ASSERT_TRUE(std::regex_search(output, message_regex));
+  }
+
+  {
+    CapturedStderr cap;
+    LOG(INFO) << "foobar";
+    ASSERT_EQ(0, lseek(cap.fd(), SEEK_SET, 0));
+
+    std::string output;
+    android::base::ReadFdToString(cap.fd(), &output);
+
+    std::regex message_regex(
+        make_log_pattern(android::base::INFO, "foobar"));
+    ASSERT_TRUE(std::regex_search(output, message_regex));
+  }
+
+  {
+    CapturedStderr cap;
+    LOG(DEBUG) << "foobar";
+    ASSERT_EQ(0, lseek(cap.fd(), SEEK_SET, 0));
+
+    std::string output;
+    android::base::ReadFdToString(cap.fd(), &output);
+    ASSERT_TRUE(output.empty());
+  }
+
+  {
+    android::base::ScopedLogSeverity severity(android::base::DEBUG);
+    CapturedStderr cap;
+    LOG(DEBUG) << "foobar";
+    ASSERT_EQ(0, lseek(cap.fd(), SEEK_SET, 0));
+
+    std::string output;
+    android::base::ReadFdToString(cap.fd(), &output);
+
+    std::regex message_regex(
+        make_log_pattern(android::base::DEBUG, "foobar"));
+    ASSERT_TRUE(std::regex_search(output, message_regex));
+  }
+}
+
+HOST_TEST(logging, PLOG) {
+  {
+    CapturedStderr cap;
+    errno = ENOENT;
+    PLOG(INFO) << "foobar";
+    ASSERT_EQ(0, lseek(cap.fd(), SEEK_SET, 0));
+
+    std::string output;
+    android::base::ReadFdToString(cap.fd(), &output);
+
+    std::regex message_regex(make_log_pattern(
+        android::base::INFO, "foobar: No such file or directory"));
+    ASSERT_TRUE(std::regex_search(output, message_regex));
+  }
+}
+
+HOST_TEST(logging, UNIMPLEMENTED) {
+  {
+    CapturedStderr cap;
+    errno = ENOENT;
+    UNIMPLEMENTED(ERROR);
+    ASSERT_EQ(0, lseek(cap.fd(), SEEK_SET, 0));
+
+    std::string output;
+    android::base::ReadFdToString(cap.fd(), &output);
+
+    std::string expected_message =
+        android::base::StringPrintf("%s unimplemented ", __PRETTY_FUNCTION__);
+    std::regex message_regex(
+        make_log_pattern(android::base::ERROR, expected_message.c_str()));
+    ASSERT_TRUE(std::regex_search(output, message_regex));
+  }
+}
diff --git a/base/test_main.cpp b/base/test_main.cpp
new file mode 100644
index 0000000..c49ca4b
--- /dev/null
+++ b/base/test_main.cpp
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include <gtest/gtest.h>
+
+#include "base/logging.h"
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  android::base::InitLogging(argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/base/test_utils.cpp b/base/test_utils.cpp
new file mode 100644
index 0000000..1f6d3cf
--- /dev/null
+++ b/base/test_utils.cpp
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include "test_utils.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+TemporaryFile::TemporaryFile() {
+  init("/data/local/tmp");
+  if (fd == -1) {
+    init("/tmp");
+  }
+}
+
+TemporaryFile::~TemporaryFile() {
+  close(fd);
+  unlink(filename);
+}
+
+void TemporaryFile::init(const char* tmp_dir) {
+  snprintf(filename, sizeof(filename), "%s/TemporaryFile-XXXXXX", tmp_dir);
+  fd = mkstemp(filename);
+}
diff --git a/base/test_utils.h b/base/test_utils.h
new file mode 100644
index 0000000..132d3a7
--- /dev/null
+++ b/base/test_utils.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef TEST_UTILS_H
+#define TEST_UTILS_H
+
+class TemporaryFile {
+ public:
+  TemporaryFile();
+  ~TemporaryFile();
+
+  int fd;
+  char filename[1024];
+
+ private:
+  void init(const char* tmp_dir);
+};
+
+#endif // TEST_UTILS_H