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1 // Copyright 2011 Google Inc. All Rights Reserved.
2 // Author: settinger@google.com (Scott Ettinger)
3 
4 // Simplified Google3 style logging with Android support.
5 // Supported macros are : LOG(INFO), LOG(WARNING), LOG(ERROR), LOG(FATAL),
6 //                        and VLOG(n).
7 //
8 // Portions of this code are taken from the GLOG package.  This code
9 // is only a small subset of the GLOG functionality. And like GLOG,
10 // higher levels are more verbose.
11 //
12 // Notable differences from GLOG :
13 //
14 // 1. lack of support for displaying unprintable characters and lack
15 // of stack trace information upon failure of the CHECK macros.
16 // 2. All output is tagged with the string "native".
17 // 3. While there is no runtime flag filtering logs (-v, -vmodule), the
18 //    compile time define MAX_LOG_LEVEL can be used to silence any
19 //    logging above the given level.
20 //
21 // -------------------------------- Usage ------------------------------------
22 // Basic usage :
23 // LOG(<severity level>) acts as a c++ stream to the Android logcat output.
24 // e.g. LOG(INFO) << "Value of counter = " << counter;
25 //
26 // Valid severity levels include INFO, WARNING, ERROR, FATAL.
27 // The various severity levels are routed to the corresponding Android logcat
28 // output.
29 // LOG(FATAL) outputs to the log and then terminates.
30 //
31 // VLOG(<severity level>) can also be used.
32 // VLOG(n) output is directed to the Android logcat levels as follows :
33 //  >=2 - Verbose
34 //    1 - Debug
35 //    0 - Info
36 //   -1 - Warning
37 //   -2 - Error
38 // <=-3 - Fatal
39 // Note that VLOG(FATAL) will terminate the program.
40 //
41 // CHECK macros are defined to test for conditions within code.  Any CHECK
42 // that fails will log the failure and terminate the application.
43 // e.g. CHECK_GE(3, 2) will pass while CHECK_GE(3, 4) will fail after logging
44 //      "Check failed 3 >= 4".
45 // The following CHECK macros are defined :
46 //
47 // CHECK(condition) - fails if condition is false and logs condition.
48 // CHECK_NOTNULL(variable) - fails if the variable is NULL.
49 //
50 // The following binary check macros are also defined :
51 //    Macro                 operator applied
52 // ------------------------------------------
53 // CHECK_EQ(val1, val2)      val1 == val2
54 // CHECK_NE(val1, val2)      val1 != val2
55 // CHECK_GT(val1, val2)      val1 > val2
56 // CHECK_GE(val1, val2)      val1 >= val2
57 // CHECK_LT(val1, val2)      val1 < val2
58 // CHECK_LE(val1, val2)      val1 <= val2
59 //
60 // Debug only versions of all of the check macros are also defined.  These
61 // macros generate no code in a release build, but avoid unused variable
62 // warnings / errors.
63 // To use the debug only versions, Prepend a D to the normal check macros.
64 // e.g. DCHECK_EQ(a, b);
65 
66 #ifndef MOBILE_BASE_LOGGING_H_
67 #define MOBILE_BASE_LOGGING_H_
68 
69 // Definitions for building on an Android system.
70 #include <android/log.h>
71 #include <time.h>
72 
73 #include <algorithm>
74 #include <iostream>
75 #include <string>
76 #include <fstream>
77 #include <set>
78 #include <sstream>
79 #include <vector>
80 
81 // Log severity level constants.
82 const int FATAL   = -3;
83 const int ERROR   = -2;
84 const int WARNING = -1;
85 const int INFO    =  0;
86 
87 // ------------------------- Glog compatibility ------------------------------
88 
89 namespace google {
90 
91 typedef int LogSeverity;
92 const int INFO    = ::INFO;
93 const int WARNING = ::WARNING;
94 const int ERROR   = ::ERROR;
95 const int FATAL   = ::FATAL;
96 
97 #ifdef ENABLE_LOG_SINKS
98 
99 // Sink class used for integration with mock and test functions.
100 // If sinks are added, all log output is also sent to each sink through
101 // the send function.  In this implementation, WaitTillSent() is called
102 // immediately after the send.
103 // This implementation is not thread safe.
104 class LogSink {
105  public:
~LogSink()106   virtual ~LogSink() {}
107   virtual void send(LogSeverity severity, const char* full_filename,
108                     const char* base_filename, int line,
109                     const struct tm* tm_time,
110                     const char* message, size_t message_len) = 0;
111   virtual void WaitTillSent() = 0;
112 };
113 
114 // Global set of log sinks.
115 // TODO(settinger): Move this into a .cc file.
116 static std::set<LogSink *> log_sinks_global;
117 
118 // Note: the Log sink functions are not thread safe.
AddLogSink(LogSink * sink)119 inline void AddLogSink(LogSink *sink) {
120   // TODO(settinger): Add locks for thread safety.
121   log_sinks_global.insert(sink);
122 }
RemoveLogSink(LogSink * sink)123 inline void RemoveLogSink(LogSink *sink) {
124   log_sinks_global.erase(sink);
125 }
126 
127 #endif  // #ifdef ENABLE_LOG_SINKS
128 
InitGoogleLogging(char * argv)129 inline void InitGoogleLogging(char *argv) {}
130 
131 }  // namespace google
132 
133 // ---------------------------- Logger Class --------------------------------
134 
135 // Class created for each use of the logging macros.
136 // The logger acts as a stream and routes the final stream contents to the
137 // Android logcat output at the proper filter level.  This class should not
138 // be directly instantiated in code, rather it should be invoked through the
139 // use of the log macros LOG, or VLOG.
140 class MessageLogger {
141  public:
MessageLogger(const char * file,int line,const char * tag,int severity)142   MessageLogger(const char *file, int line, const char *tag, int severity)
143     : file_(file), line_(line), tag_(tag), severity_(severity) {
144     // Pre-pend the stream with the file and line number.
145     StripBasename(std::string(file), &filename_only_);
146     stream_ << filename_only_ << ":" << line << " ";
147   }
148 
149   // Output the contents of the stream to the proper channel on destruction.
~MessageLogger()150   ~MessageLogger() {
151 #ifdef MAX_LOG_LEVEL
152     if (severity_ > MAX_LOG_LEVEL && severity_ > FATAL) {
153       return;
154     }
155 #endif
156     stream_ << "\n";
157     static const int android_log_levels[] = {
158         ANDROID_LOG_FATAL,    // LOG(FATAL)
159         ANDROID_LOG_ERROR,    // LOG(ERROR)
160         ANDROID_LOG_WARN,     // LOG(WARNING)
161         ANDROID_LOG_INFO,     // LOG(INFO), VLOG(0)
162         ANDROID_LOG_DEBUG,    // VLOG(1)
163         ANDROID_LOG_VERBOSE,  // VLOG(2) .. VLOG(N)
164     };
165 
166     // Bound the logging level.
167     const int kMaxVerboseLevel = 2;
168     int android_level_index = std::min(std::max(FATAL, severity_),
169                                        kMaxVerboseLevel) - FATAL;
170     int android_log_level = android_log_levels[android_level_index];
171 
172     // Output the log string the Android log at the appropriate level.
173     __android_log_write(android_log_level, tag_.c_str(), stream_.str().c_str());
174 
175     // Indicate termination if needed.
176     if (severity_ == FATAL) {
177       __android_log_write(ANDROID_LOG_FATAL,
178                           tag_.c_str(),
179                           "terminating.\n");
180     }
181 
182 #ifdef ENABLE_LOG_SINKS
183 
184     LogToSinks(severity_);
185     WaitForSinks();
186 
187 #endif  // #ifdef ENABLE_LOG_SINKS
188 
189     // Android logging at level FATAL does not terminate execution, so abort()
190     // is still required to stop the program.
191     if (severity_ == FATAL) {
192       abort();
193     }
194   }
195 
196   // Return the stream associated with the logger object.
stream()197   std::stringstream &stream() { return stream_; }
198 
199  private:
200 #ifdef ENABLE_LOG_SINKS
201 
LogToSinks(int severity)202   void LogToSinks(int severity) {
203     time_t rawtime;
204     struct tm * timeinfo;
205 
206     time ( &rawtime );
207     timeinfo = localtime ( &rawtime );
208     std::set<google::LogSink *>::iterator iter;
209     // Send the log message to all sinks.
210     for (iter = google::log_sinks_global.begin();
211          iter != google::log_sinks_global.end(); ++iter)
212       (*iter)->send(severity, file_.c_str(), filename_only_.c_str(), line_,
213                     timeinfo, stream_.str().c_str(), stream_.str().size());
214   }
215 
WaitForSinks()216   void WaitForSinks() {
217     // TODO(settinger): add locks for thread safety.
218     std::set<google::LogSink *>::iterator iter;
219     // Call WaitTillSent() for all sinks.
220     for (iter = google::log_sinks_global.begin();
221          iter != google::log_sinks_global.end(); ++iter)
222       (*iter)->WaitTillSent();
223   }
224 
225 #endif // #ifdef ENABLE_LOG_SINKS
226 
StripBasename(const std::string & full_path,std::string * filename)227   void StripBasename(const std::string &full_path, std::string *filename) {
228     // TODO(settinger): add support for OS with different path separators.
229     const char kSeparator = '/';
230     size_t pos = full_path.rfind(kSeparator);
231     if (pos != std::string::npos)
232       *filename = full_path.substr(pos + 1, std::string::npos);
233     else
234       *filename = full_path;
235   }
236 
237   std::string file_;
238   std::string filename_only_;
239   int line_;
240   std::string tag_;
241   std::stringstream stream_;
242   int severity_;
243 };
244 
245 // ---------------------- Logging Macro definitions --------------------------
246 
247 // This class is used to explicitly ignore values in the conditional
248 // logging macros.  This avoids compiler warnings like "value computed
249 // is not used" and "statement has no effect".
250 class LoggerVoidify {
251  public:
LoggerVoidify()252   LoggerVoidify() { }
253   // This has to be an operator with a precedence lower than << but
254   // higher than ?:
255   void operator&(const std::ostream &s) { }
256 };
257 
258 // Log only if condition is met.  Otherwise evaluates to void.
259 #define LOG_IF(severity, condition) \
260   !(condition) ? (void) 0 : LoggerVoidify() & \
261     MessageLogger((char *)__FILE__, __LINE__, "native", severity).stream()
262 
263 // Log only if condition is NOT met.  Otherwise evaluates to void.
264 #define LOG_IF_FALSE(severity, condition) LOG_IF(severity, !(condition))
265 
266 // LG is a convenient shortcut for LOG(INFO). Its use is in new
267 // google3 code is discouraged and the following shortcut exists for
268 // backward compatibility with existing code.
269 #ifdef MAX_LOG_LEVEL
270 #define LOG(n) LOG_IF(n, n <= MAX_LOG_LEVEL)
271 #define VLOG(n) LOG_IF(n, n <= MAX_LOG_LEVEL)
272 #define LG LOG_IF(INFO, INFO <= MAX_LOG_LEVEL)
273 #else
274 #define LOG(n) MessageLogger((char *)__FILE__, __LINE__, "native", n).stream()
275 #define VLOG(n) MessageLogger((char *)__FILE__, __LINE__, "native", n).stream()
276 #define LG MessageLogger((char *)__FILE__, __LINE__, "native", INFO).stream()
277 #endif
278 
279 // Currently, VLOG is always on for levels below MAX_LOG_LEVEL.
280 #ifndef MAX_LOG_LEVEL
281 #define VLOG_IS_ON(x) (1)
282 #else
283 #define VLOG_IS_ON(x) (x <= MAX_LOG_LEVEL)
284 #endif
285 
286 #ifndef NDEBUG
287 #define DLOG LOG
288 #else
289 #define DLOG(severity) true ? (void) 0 : LoggerVoidify() & \
290     MessageLogger((char *)__FILE__, __LINE__, "native", severity).stream()
291 #endif
292 
293 // ---------------------------- CHECK helpers --------------------------------
294 
295 // Log a message and terminate.
296 template<class T>
LogMessageFatal(const char * file,int line,const T & message)297 void LogMessageFatal(const char *file, int line, const T &message) {
298   MessageLogger((char *)__FILE__, __LINE__, "native", FATAL).stream()
299       << message;
300 }
301 
302 // ---------------------------- CHECK macros ---------------------------------
303 
304 // Check for a given boolean condition.
305 #define CHECK(condition) LOG_IF_FALSE(FATAL, condition) \
306         << "Check failed: " #condition " "
307 
308 #ifndef NDEBUG
309 // Debug only version of CHECK
310 #define DCHECK(condition) LOG_IF_FALSE(FATAL, condition) \
311         << "Check failed: " #condition " "
312 #else
313 // Optimized version - generates no code.
314 #define DCHECK(condition) if (false) LOG_IF_FALSE(FATAL, condition) \
315         << "Check failed: " #condition " "
316 #endif  // NDEBUG
317 
318 // ------------------------- CHECK_OP macros ---------------------------------
319 
320 // Generic binary operator check macro. This should not be directly invoked,
321 // instead use the binary comparison macros defined below.
322 #define CHECK_OP(val1, val2, op) LOG_IF_FALSE(FATAL, (val1 op val2)) \
323   << "Check failed: " #val1 " " #op " " #val2 " "
324 
325 // Check_op macro definitions
326 #define CHECK_EQ(val1, val2) CHECK_OP(val1, val2, ==)
327 #define CHECK_NE(val1, val2) CHECK_OP(val1, val2, !=)
328 #define CHECK_LE(val1, val2) CHECK_OP(val1, val2, <=)
329 #define CHECK_LT(val1, val2) CHECK_OP(val1, val2, <)
330 #define CHECK_GE(val1, val2) CHECK_OP(val1, val2, >=)
331 #define CHECK_GT(val1, val2) CHECK_OP(val1, val2, >)
332 
333 #ifndef NDEBUG
334 // Debug only versions of CHECK_OP macros.
335 #define DCHECK_EQ(val1, val2) CHECK_OP(val1, val2, ==)
336 #define DCHECK_NE(val1, val2) CHECK_OP(val1, val2, !=)
337 #define DCHECK_LE(val1, val2) CHECK_OP(val1, val2, <=)
338 #define DCHECK_LT(val1, val2) CHECK_OP(val1, val2, <)
339 #define DCHECK_GE(val1, val2) CHECK_OP(val1, val2, >=)
340 #define DCHECK_GT(val1, val2) CHECK_OP(val1, val2, >)
341 #else
342 // These versions generate no code in optimized mode.
343 #define DCHECK_EQ(val1, val2) if (false) CHECK_OP(val1, val2, ==)
344 #define DCHECK_NE(val1, val2) if (false) CHECK_OP(val1, val2, !=)
345 #define DCHECK_LE(val1, val2) if (false) CHECK_OP(val1, val2, <=)
346 #define DCHECK_LT(val1, val2) if (false) CHECK_OP(val1, val2, <)
347 #define DCHECK_GE(val1, val2) if (false) CHECK_OP(val1, val2, >=)
348 #define DCHECK_GT(val1, val2) if (false) CHECK_OP(val1, val2, >)
349 #endif  // NDEBUG
350 
351 // ---------------------------CHECK_NOTNULL macros ---------------------------
352 
353 // Helpers for CHECK_NOTNULL(). Two are necessary to support both raw pointers
354 // and smart pointers.
355 template <typename T>
CheckNotNullCommon(const char * file,int line,const char * names,T & t)356 T& CheckNotNullCommon(const char *file, int line, const char *names, T& t) {
357   if (t == NULL) {
358     LogMessageFatal(file, line, std::string(names));
359   }
360   return t;
361 }
362 
363 template <typename T>
CheckNotNull(const char * file,int line,const char * names,T * t)364 T* CheckNotNull(const char *file, int line, const char *names, T* t) {
365   return CheckNotNullCommon(file, line, names, t);
366 }
367 
368 template <typename T>
CheckNotNull(const char * file,int line,const char * names,T & t)369 T& CheckNotNull(const char *file, int line, const char *names, T& t) {
370   return CheckNotNullCommon(file, line, names, t);
371 }
372 
373 // Check that a pointer is not null.
374 #define CHECK_NOTNULL(val) \
375   CheckNotNull(__FILE__, __LINE__, "'" #val "' Must be non NULL", (val))
376 
377 #ifndef NDEBUG
378 // Debug only version of CHECK_NOTNULL
379 #define DCHECK_NOTNULL(val) \
380   CheckNotNull(__FILE__, __LINE__, "'" #val "' Must be non NULL", (val))
381 #else
382 // Optimized version - generates no code.
383 #define DCHECK_NOTNULL(val) if (false)\
384   CheckNotNull(__FILE__, __LINE__, "'" #val "' Must be non NULL", (val))
385 #endif  // NDEBUG
386 
PrintAndroid(const char * msg)387 inline void PrintAndroid(const char *msg) {
388   __android_log_write(ANDROID_LOG_VERBOSE, "native", msg);
389 }
390 
391 #endif  // MOBILE_BASE_LOGGING_H_
392