Scott Anderson | b0114cb | 2012-04-09 14:08:22 -0700 | [diff] [blame] | 1 | // Copyright 2009 Google Inc. All Rights Reserved. |
| 2 | |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | #ifndef STRESSAPPTEST_LOGGER_H_ |
| 16 | #define STRESSAPPTEST_LOGGER_H_ |
| 17 | |
| 18 | #include <pthread.h> |
| 19 | #include <stdarg.h> |
| 20 | |
| 21 | #include <string> |
| 22 | #include <vector> |
| 23 | |
| 24 | // This file must work with autoconf on its public version, |
| 25 | // so these includes are correct. |
| 26 | #include "sattypes.h" |
| 27 | |
| 28 | // Attempts to log additional lines will block when the queue reaches this size. |
| 29 | // Due to how the logging thread works, up to twice this many log lines may be |
| 30 | // outstanding at any point. |
| 31 | static const size_t kMaxQueueSize = 250; |
| 32 | |
| 33 | |
| 34 | // This is only for use by the Logger class, do not use it elsewhere! |
| 35 | // |
| 36 | // All Logger assertions should use this macro instead of sat_assert(). |
| 37 | // |
| 38 | // This is like sat_assert() from sattypes.h, but whereas sat_assert() tries to |
| 39 | // log the assertion after printing it to stderr, this only prints it to stderr. |
| 40 | // Logging from within the wrong part of the logger would trigger a deadlock, |
| 41 | // and even in places where it wouldn't there's a very good chance that the |
| 42 | // logger is in no condition to handle new log lines. |
| 43 | #define LOGGER_ASSERT(x) \ |
| 44 | {\ |
| 45 | if (!(x)) {\ |
| 46 | fprintf(stderr, "Assertion failed at %s:%d\n", __FILE__, __LINE__);\ |
| 47 | exit(1);\ |
| 48 | }\ |
| 49 | } |
| 50 | |
| 51 | |
| 52 | // This class handles logging in SAT. It is a singleton accessed via |
| 53 | // GlobalLogger(). |
| 54 | // |
| 55 | // By default log lines are written in the calling thread. Call StartThread() |
| 56 | // to launch a dedicated thread for the writes. |
| 57 | class Logger { |
| 58 | public: |
| 59 | // Returns a pointer to the single global Logger instance. Will not return |
| 60 | // NULL. |
| 61 | static Logger *GlobalLogger(); |
| 62 | |
| 63 | // Lines with a priority numerically greater than this will not be logged. |
| 64 | // May not be called while multiple threads are running. |
| 65 | void SetVerbosity(int verbosity) { |
| 66 | verbosity_ = verbosity; |
| 67 | } |
| 68 | |
| 69 | // Sets a file to log to, in addition to stdout. May not be called while |
| 70 | // multiple threads are running. |
| 71 | // |
| 72 | // Args: |
| 73 | // log_fd: The file descriptor to write to. Will not be closed by this |
| 74 | // object. |
| 75 | void SetLogFd(int log_fd) { |
| 76 | LOGGER_ASSERT(log_fd >= 0); |
| 77 | log_fd_ = log_fd; |
| 78 | } |
| 79 | |
| 80 | // Set output to be written to stdout only. This is the default mode. May |
| 81 | // not be called while multiple threads are running. |
| 82 | void SetStdoutOnly() { |
| 83 | log_fd_ = -1; |
| 84 | } |
| 85 | |
| 86 | // Logs a line, with a vprintf(3)-like interface. This will block on writing |
| 87 | // the line to stdout/disk iff the dedicated logging thread is not running. |
| 88 | // This will block on adding the line to the queue if doing so would exceed |
| 89 | // kMaxQueueSize. |
| 90 | // |
| 91 | // Args: |
| 92 | // priority: If this is numerically greater than the verbosity, the line |
| 93 | // will not be logged. |
| 94 | // format: see vprintf(3) |
| 95 | // args: see vprintf(3) |
| 96 | void VLogF(int priority, const char *format, va_list args); |
| 97 | |
| 98 | // Starts the dedicated logging thread. May not be called while multiple |
| 99 | // threads are already running. |
| 100 | void StartThread(); |
| 101 | |
| 102 | // Stops the dedicated logging thread. May only be called when the logging |
| 103 | // thread is the only other thread running. Any queued lines will be logged |
| 104 | // before this returns. Waits for the thread to finish before returning. |
| 105 | void StopThread(); |
| 106 | |
| 107 | private: |
| 108 | Logger(); |
| 109 | |
| 110 | ~Logger(); |
| 111 | |
| 112 | // Args: |
| 113 | // line: Must be non-NULL. This function takes ownership of it. |
| 114 | void QueueLogLine(string *line); |
| 115 | |
| 116 | // Args: |
| 117 | // line: Must be non-NULL. This function takes ownership of it. |
| 118 | void WriteAndDeleteLogLine(string *line); |
| 119 | |
| 120 | // Callback for pthread_create(3). |
| 121 | static void *StartRoutine(void *ptr); |
| 122 | |
| 123 | // Processes the log queue. |
| 124 | void ThreadMain(); |
| 125 | |
| 126 | pthread_t thread_; |
| 127 | int verbosity_; |
| 128 | int log_fd_; |
| 129 | bool thread_running_; |
| 130 | vector<string*> queued_lines_; |
| 131 | // This doubles as a mutex for log_fd_ when the logging thread is not running. |
| 132 | pthread_mutex_t queued_lines_mutex_; |
| 133 | // Lets the logging thread know that the queue is no longer empty. |
| 134 | pthread_cond_t queued_lines_cond_; |
| 135 | // Lets the threads blocked on the queue having reached kMaxQueueSize know |
| 136 | // that the queue has been emptied. |
| 137 | pthread_cond_t full_queue_cond_; |
| 138 | |
| 139 | DISALLOW_COPY_AND_ASSIGN(Logger); |
| 140 | }; |
| 141 | |
| 142 | #endif // STRESSAPPTEST_LOGGER_H_ |