Add support of rotating log to file with specified prefix. (#202)

Author: taste1981

rtc_base/file_rotating_stream.cc

@@ -351,6 +351,19 @@ CallSessionFileRotatingStream::CallSessionFileRotatingStream(
   RTC_DCHECK_GE(max_total_log_size, 4);
 }
 
+CallSessionFileRotatingStream::CallSessionFileRotatingStream(
+    absl::string_view dir_path,
+    absl::string_view log_file_prefix,
+    size_t max_total_log_size)
+    : FileRotatingStream(dir_path,
+                         log_file_prefix,
+                         max_total_log_size / 2,
+                         GetNumRotatingLogFiles(max_total_log_size) + 1),
+      max_total_log_size_(max_total_log_size),
+      num_rotations_(0) {
+  RTC_DCHECK_GE(max_total_log_size, 4);
+}
+
 const size_t CallSessionFileRotatingStream::kRotatingLogFileDefaultSize =
     1024 * 1024;
 
@@ -425,4 +438,9 @@ CallSessionFileRotatingStreamReader::CallSessionFileRotatingStreamReader(
     absl::string_view dir_path)
     : FileRotatingStreamReader(dir_path, kCallSessionLogPrefix) {}
 
+CallSessionFileRotatingStreamReader::CallSessionFileRotatingStreamReader(
+    absl::string_view dir_path,
+    absl::string_view log_file_prefix)
+    : FileRotatingStreamReader(dir_path, log_file_prefix) {}
+
 }  // namespace rtc

rtc_base/file_rotating_stream.h

@@ -129,6 +129,14 @@ class CallSessionFileRotatingStream : public FileRotatingStream {
   // must be at least 4.
   CallSessionFileRotatingStream(absl::string_view dir_path,
                                 size_t max_total_log_size);
+
+  // Use this constructor for writing to a directory. Files in the directory
+  // matching what's used by the stream will be deleted. 'max_totla_log_size'
+  // must be at least 4. file name will be prefixed with 'log_file_prefix'.
+  CallSessionFileRotatingStream(absl::string_view dir_path,
+                                absl::string_view log_file_prefix,
+                                size_t max_total_log_size);
+
   ~CallSessionFileRotatingStream() override {}
 
   CallSessionFileRotatingStream(const CallSessionFileRotatingStream&) = delete;
@@ -166,6 +174,8 @@ class FileRotatingStreamReader {
 class CallSessionFileRotatingStreamReader : public FileRotatingStreamReader {
  public:
   CallSessionFileRotatingStreamReader(absl::string_view dir_path);
+
+  CallSessionFileRotatingStreamReader(absl::string_view dir_path, absl::string_view long_file_prefix);
 };
 
 }  // namespace rtc

rtc_base/log_sinks.cc

@@ -81,6 +81,15 @@ CallSessionFileRotatingLogSink::CallSessionFileRotatingLogSink(
           new CallSessionFileRotatingStream(log_dir_path, max_total_log_size)) {
 }
 
+CallSessionFileRotatingLogSink::CallSessionFileRotatingLogSink(
+    absl::string_view log_dir_path,
+    absl::string_view log_file_prefix,
+    size_t max_total_log_size)
+    : FileRotatingLogSink(
+          new CallSessionFileRotatingStream(log_dir_path, log_file_prefix, max_total_log_size)) {
+}
+
+
 CallSessionFileRotatingLogSink::~CallSessionFileRotatingLogSink() {}
 
 }  // namespace rtc

rtc_base/log_sinks.h

@@ -67,6 +67,9 @@ class CallSessionFileRotatingLogSink : public FileRotatingLogSink {
  public:
   CallSessionFileRotatingLogSink(absl::string_view log_dir_path,
                                  size_t max_total_log_size);
+  CallSessionFileRotatingLogSink(absl::string_view log_dir_path,
+                                 absl::string_view log_file_prefix,
+                                 size_t max_total_log_size);
   ~CallSessionFileRotatingLogSink() override;
 
   CallSessionFileRotatingLogSink(const CallSessionFileRotatingLogSink&) =