SingleLogSource handles rotation of log files

chrome/browser/chromeos/system_logs/single_log_source.h

Index: chrome/browser/chromeos/system_logs/single_log_source.h
diff --git a/chrome/browser/chromeos/system_logs/single_log_source.h b/chrome/browser/chromeos/system_logs/single_log_source.h
index 2ffe730d9a7a59eb2910de1ab893397b4580d238..d4ddaa63d189c3ca479af43037b685bba100b6f5 100644
--- a/chrome/browser/chromeos/system_logs/single_log_source.h
+++ b/chrome/browser/chromeos/system_logs/single_log_source.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_SINGLE_LOG_SOURCE_H_
 
 #include <stddef.h>
+#include <sys/types.h>
 
 #include "base/files/file.h"
 #include "base/macros.h"
@@ -34,8 +35,23 @@ class SingleLogSource : public SystemLogsSource {
  private:
   friend class SingleLogSourceTest;
 
+  // Returns the full path of the log file.
+  base::FilePath GetLogFilePath() const;
+
   // Reads all available content from |file_| that has not already been read.
-  void ReadFile(SystemLogsResponse* result);
+  // Stores results as a single entry in |result|, with |source_name()| as key
+  // and the read log contents as value.
+  //
+  // Handles rotation of underlying log file by reading all remaining contents
+  // of old file and then opening and reading from new file.
+  //
+  // |num_rotations_allowed| limits the number of rotations that can take place
+  // before the function returns. This avoids this function never returning due
+  // to indefinitely repeated log file rotation. If this number is exceeded
+  // during a call, ReadFile() stops checking for log file rotation for the
+  // remainder of its execution. Any further rotation could result in missed log
+  // data.
+  void ReadFile(size_t num_rotations_allowed, SystemLogsResponse* result);
 
   // Path to system log file directory.
   base::FilePath log_file_dir_path_;
@@ -46,6 +62,10 @@ class SingleLogSource : public SystemLogsSource {
   // Handle for reading the log file that is source of logging data.
   base::File file_;
 
+  // File system inode value that was associated with |log_file_path_| when it
+  // was originally opened for reading.
+  ino_t file_inode_;
+
   // For removing PII from log results.
   feedback::AnonymizerTool anonymizer_;