AppRTCDemo file logging.

talk/app/webrtc/objc/public/RTCFileLogger.h

+/*
+ * libjingle
+ * Copyright 2015 Google Inc.
+ *
+ * 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. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+
+#import <Foundation/Foundation.h>
+
+// TODO(tkchin): Move this to a common location.
+#ifndef NS_DESIGNATED_INITIALIZER
+#define NS_DESIGNATED_INITIALIZER
+#endif
+
+typedef NS_ENUM(NSUInteger, RTCFileLoggerSeverity) {
+  kRTCFileLoggerSeverityVerbose,
+  kRTCFileLoggerSeverityInfo,
+  kRTCFileLoggerSeverityWarning,
+  kRTCFileLoggerSeverityError
+};
+
+// This class intercepts WebRTC logs and saves them to a file. The file size
+// will not exceed the given maximum bytesize. When the maximum bytesize is
+// reached logs from the beginning and the end are preserved while the middle
+// section is overwritten instead.
+// This class is not threadsafe.
+@interface RTCFileLogger : NSObject
+
+// The severity level to capture. The default is kRTCFileLoggerSeverityInfo.
+@property(nonatomic, assign) RTCFileLoggerSeverity severity;
+
+// Default constructor provides default settings for file path and file size.
+- (instancetype)init;
+
+- (instancetype)initWithFilePath:(NSString *)filePath
+                     maxFileSize:(NSUInteger)maxFileSize
+    NS_DESIGNATED_INITIALIZER;
+
+// Starts writing WebRTC logs to file if not already started. Overwrites any
+// existing file.
+- (void)start;
+
+// Stops writing WebRTC logs to file. Rewrites the log file as required to
+// reorder logs because logs may be disordered due to use of
+// rtc::CircularFileStream. This method is also called on dealloc.
+- (void)stop;
+
+// Returns the current contents of the log file. Returns nil if start has been
+// called without a stop, or if there is no data.
+- (NSData *)logData;
+
+@end