// Copyright 2019 The Dawn & Tint Authors // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are met: // // 1. Redistributions of source code must retain the above copyright notice, this // list of conditions and the following disclaimer. // // 2. Redistributions in binary form must reproduce the above copyright notice, // this list of conditions and the following disclaimer in the documentation // and/or other materials provided with the distribution. // // 3. Neither the name of the copyright holder nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #ifndef SRC_DAWN_COMMON_LOG_H_ #define SRC_DAWN_COMMON_LOG_H_ // Dawn targets shouldn't use iostream or printf directly for several reasons: // - iostream adds static initializers which we want to avoid. // - printf and iostream don't show up in logcat on Android so printf debugging doesn't work but // log-message debugging does. // - log severity helps provide intent compared to a printf. // // Logging should in general be avoided: errors should go through the regular WebGPU error reporting // mechanism and others form of logging should (TODO: eventually) go through the logging dependency // injection, so for example they show up in Chromium's about:gpu page. Nonetheless there are some // cases where logging is necessary and when this file was first introduced we needed to replace all // uses of iostream so we could see them in Android's logcat. // // Regular logging is done using the [Debug|Info|Warning|Error]Log() function this way: // // InfoLog() << things << that << ostringstream << supports; // No need for a std::endl or "\n" // // It creates a LogMessage object that isn't stored anywhere and gets its destructor called // immediately which outputs the stored ostringstream in the right place. // // This file also contains DAWN_DEBUG for "printf debugging" which works on Android and // additionally outputs the file, line and function name. Use it this way: // // // Pepper this throughout code to get a log of the execution // DAWN_DEBUG(); // // // Get more information // DAWN_DEBUG() << texture.GetFormat(); #include <sstream> namespace dawn { // Log levels mostly used to signal intent where the log message is produced and used to route // the message to the correct output. enum class LogSeverity { … }; // Essentially an ostringstream that will print itself in its destructor. class LogMessage { … }; // Short-hands to create a LogMessage with the respective severity. LogMessage DebugLog(); LogMessage InfoLog(); LogMessage WarningLog(); LogMessage ErrorLog(); // DAWN_DEBUG is a helper macro that creates a DebugLog and outputs file/line/function // information LogMessage DebugLog(const char* file, const char* function, int line); #define DAWN_DEBUG() … } // namespace dawn #endif // SRC_DAWN_COMMON_LOG_H_