Add rotating log file stream.

webrtc/base/filerotatingstream.cc

+/*
+ *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/base/filerotatingstream.h"
+
+#include <algorithm>
+#include <iostream>
+#include <string>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/fileutils.h"
+#include "webrtc/base/pathutils.h"
+
+// Note: We use std::cerr for logging in the write paths of this stream to avoid
+// infinite loops when logging.
+
+namespace rtc {
+
+FileRotatingStream::FileRotatingStream(const std::string& dir_path,
+                                       const std::string& file_prefix)
+    : FileRotatingStream(dir_path, file_prefix, 0, 0, kRead) {
+}
+
+FileRotatingStream::FileRotatingStream(const std::string& dir_path,
+                                       const std::string& file_prefix,
+                                       size_t max_file_size,
+                                       size_t num_files)
+    : FileRotatingStream(dir_path,
+                         file_prefix,
+                         max_file_size,
+                         num_files,
+                         kWrite) {
+  DCHECK_GT(max_file_size, 0u);
+  DCHECK_GT(num_files, 1u);
+}
+
+FileRotatingStream::FileRotatingStream(const std::string& dir_path,
+                                       const std::string& file_prefix,
+                                       size_t max_file_size,
+                                       size_t num_files,
+                                       Mode mode)
+    : dir_path_(dir_path),
+      file_prefix_(file_prefix),
+      mode_(mode),
+      file_stream_(nullptr),
+      max_file_size_(max_file_size),
+      current_file_index_(0),
+      rotation_index_(0),
+      current_bytes_written_(0),
+      disable_buffering_(false) {
+  DCHECK(Filesystem::IsFolder(dir_path));
+  switch (mode) {
+    case kWrite: {
+      file_names_.clear();
+      for (size_t i = 0; i < num_files; ++i) {
+        file_names_.push_back(GetFilePath(i, num_files));
+      }
+      rotation_index_ = num_files - 1;
+      break;
+    }
+    case kRead: {
+      file_names_ = GetFilesWithPrefix();
+      std::sort(file_names_.begin(), file_names_.end());
+      if (file_names_.size() > 0) {
+        // |file_names_| is sorted newest first, so read from the end.
+        current_file_index_ = file_names_.size() - 1;
+      }
+      break;
+    }
+  }
+}
+
+FileRotatingStream::~FileRotatingStream() {
+}
+
+StreamState FileRotatingStream::GetState() const {
+  if (mode_ == kRead && current_file_index_ < file_names_.size()) {
+    return SS_OPEN;
+  }
+  if (!file_stream_) {
+    return SS_CLOSED;
+  }
+  return file_stream_->GetState();
+}
+
+StreamResult FileRotatingStream::Read(void* buffer,
+                                      size_t buffer_len,
+                                      size_t* read,
+                                      int* error) {
+  DCHECK(buffer);
+  if (mode_ != kRead) {
+    return SR_EOS;
+  }
+  if (current_file_index_ >= file_names_.size()) {
+    return SR_EOS;
+  }
+  // We will have no file stream initially, and when we are finished with the
+  // previous file.
+  if (!file_stream_) {
+    if (!OpenCurrentFile()) {
+      return SR_ERROR;
+    }
+  }
+  int local_error = 0;
+  if (!error) {
+    error = &local_error;
+  }
+  StreamResult result = file_stream_->Read(buffer, buffer_len, read, error);
+  if (result == SR_EOS || result == SR_ERROR) {
+    if (result == SR_ERROR) {
+      LOG(LS_ERROR) << "Failed to read from: "
+                    << file_names_[current_file_index_] << "Error: " << error;
+    }
+    // Reached the end of the file, read next file. If there is an error return
+    // the error status but allow for a next read by reading next file.
+    CloseCurrentFile();
+    if (current_file_index_ == 0) {
+      // Just finished reading the last file, signal EOS by setting index.
+      current_file_index_ = file_names_.size();
+    } else {
+      --current_file_index_;
+    }
+    if (read) {
+      *read = 0;
+    }
+    return result == SR_EOS ? SR_SUCCESS : result;
+  } else if (result == SR_SUCCESS) {
+    // Succeeded, continue reading from this file.
+    return SR_SUCCESS;
+  } else {
+    RTC_NOTREACHED();
+  }
+  return result;
+}
+
+StreamResult FileRotatingStream::Write(const void* data,
+                                       size_t data_len,
+                                       size_t* written,
+                                       int* error) {
+  if (mode_ != kWrite) {
+    return SR_EOS;
+  }
+  if (!file_stream_) {
+    std::cerr << "Open() must be called before Write." << std::endl;
+    return SR_ERROR;
+  }
+  // Write as much as will fit in to the current file.
+  DCHECK_LT(current_bytes_written_, max_file_size_);
+  size_t remaining_bytes = max_file_size_ - current_bytes_written_;
+  size_t write_length = std::min(data_len, remaining_bytes);
+  size_t local_written = 0;
+  if (!written) {
+    written = &local_written;
+  }
+  StreamResult result = file_stream_->Write(data, write_length, written, error);
+  current_bytes_written_ += *written;
+
+  // If we're done with this file, rotate it out.
+  if (current_bytes_written_ >= max_file_size_) {
+    DCHECK_EQ(current_bytes_written_, max_file_size_);
+    RotateFiles();
+  }
+  return result;
+}
+
+bool FileRotatingStream::Flush() {
+  if (!file_stream_) {
+    return false;
+  }
+  return file_stream_->Flush();
+}
+
+void FileRotatingStream::Close() {
+  CloseCurrentFile();
+}
+
+bool FileRotatingStream::Open() {
+  switch (mode_) {
+    case kRead:
+      // Defer opening to when we first read since we want to return read error
+      // if we fail to open next file.
+      return true;
+    case kWrite: {
+      // Delete existing files when opening for write.
+      std::vector<std::string> matching_files = GetFilesWithPrefix();
+      for (auto matching_file : matching_files) {
+        if (!Filesystem::DeleteFile(matching_file)) {
+          std::cerr << "Failed to delete: " << matching_file << std::endl;
+        }
+      }
+      return OpenCurrentFile();
+    }
+  }
+  return false;
+}
+
+bool FileRotatingStream::DisableBuffering() {
+  disable_buffering_ = true;
+  if (!file_stream_) {
+    std::cerr << "Open() must be called before DisableBuffering()."
+              << std::endl;
+    return false;
+  }
+  return file_stream_->DisableBuffering();
+}
+
+std::string FileRotatingStream::GetFilePath(size_t index) const {
+  DCHECK_LT(index, file_names_.size());
+  return file_names_[index];
+}
+
+bool FileRotatingStream::OpenCurrentFile() {
+  CloseCurrentFile();
+
+  // Opens the appropriate file in the appropriate mode.
+  DCHECK_LT(current_file_index_, file_names_.size());
+  std::string file_path = file_names_[current_file_index_];
+  file_stream_.reset(new FileStream());
+  const char* mode = nullptr;
+  switch (mode_) {
+    case kWrite:
+      mode = "w+";
+      // We should always we writing to the zero-th file.
+      DCHECK_EQ(current_file_index_, 0u);
+      break;
+    case kRead:
+      mode = "r";
+      break;
+  }
+  int error = 0;
+  if (!file_stream_->Open(file_path, mode, &error)) {
+    std::cerr << "Failed to open: " << file_path << "Error: " << error
+              << std::endl;
+    file_stream_.reset();
+    return false;
+  }
+  if (disable_buffering_) {
+    file_stream_->DisableBuffering();
+  }
+  return true;
+}
+
+void FileRotatingStream::CloseCurrentFile() {
+  if (!file_stream_) {
+    return;
+  }
+  current_bytes_written_ = 0;
+  file_stream_.reset();
+}
+
+void FileRotatingStream::RotateFiles() {
+  DCHECK_EQ(mode_, kWrite);
+  CloseCurrentFile();
+  // Rotates the files by deleting the file at |rotation_index_|, which is the
+  // oldest file and then renaming the newer files to have an incremented index.
+  // See header file comments for example.
+  DCHECK_LE(rotation_index_, file_names_.size());
+  std::string file_to_delete = file_names_[rotation_index_];
+  if (Filesystem::IsFile(file_to_delete)) {
+    if (!Filesystem::DeleteFile(file_to_delete)) {
+      std::cerr << "Failed to delete: " << file_to_delete << std::endl;
+    }
+  }
+  for (auto i = rotation_index_; i > 0; --i) {
+    std::string rotated_name = file_names_[i];
+    std::string unrotated_name = file_names_[i - 1];
+    if (Filesystem::IsFile(unrotated_name)) {
+      if (!Filesystem::MoveFile(unrotated_name, rotated_name)) {
+        std::cerr << "Failed to move: " << unrotated_name << " to "
+                  << rotated_name << std::endl;
+      }
+    }
+  }
+  // Create a new file for 0th index.
+  OpenCurrentFile();
+  OnRotation();
+}
+
+std::vector<std::string> FileRotatingStream::GetFilesWithPrefix() const {
+  std::vector<std::string> files;
+  // Iterate over the files in the directory.
+  DirectoryIterator it;
+  Pathname dir_path;
+  dir_path.SetFolder(dir_path_);
+  if (!it.Iterate(dir_path)) {
+    return files;
+  }
+  do {
+    std::string current_name = it.Name();
+    if (current_name.size() && !it.IsDirectory() &&
+        current_name.compare(0, file_prefix_.size(), file_prefix_) == 0) {
+      Pathname path(dir_path_, current_name);
+      files.push_back(path.pathname());
+    }
+  } while (it.Next());
+  return files;
+}
+
+std::string FileRotatingStream::GetFilePath(size_t index,
+                                            size_t num_files) const {
+  DCHECK_LT(index, num_files);
+  std::ostringstream file_name;
+  // The format will be "_%<num_digits>zu". We want to zero pad the index so
+  // that it will sort nicely.
+  size_t max_digits = ((num_files - 1) / 10) + 1;
+  size_t num_digits = (index / 10) + 1;
+  DCHECK_LE(num_digits, max_digits);
+  size_t padding = max_digits - num_digits;
+
+  file_name << file_prefix_ << "_";
+  for (size_t i = 0; i < padding; ++i) {
+    file_name << "0";
+  }
+  file_name << index;
+
+  Pathname file_path(dir_path_, file_name.str());
+  return file_path.pathname();
+}
+
+CallSessionFileRotatingStream::CallSessionFileRotatingStream(
+    const std::string& dir_path)
+    : FileRotatingStream(dir_path, kLogPrefix),
+      max_total_log_size_(0),
+      num_rotations_(0) {
+}
+
+CallSessionFileRotatingStream::CallSessionFileRotatingStream(
+    const std::string& dir_path,
+    size_t max_total_log_size)
+    : FileRotatingStream(dir_path,
+                         kLogPrefix,
+                         max_total_log_size / 2,
+                         GetNumRotatingLogFiles(max_total_log_size) + 1),
+      max_total_log_size_(max_total_log_size),
+      num_rotations_(0) {
+  DCHECK_GE(max_total_log_size, 4u);
+}
+
+const char* CallSessionFileRotatingStream::kLogPrefix = "webrtc_log";
+const size_t CallSessionFileRotatingStream::kRotatingLogFileDefaultSize =
+    1024 * 1024;
+
+void CallSessionFileRotatingStream::OnRotation() {
+  ++num_rotations_;
+  if (num_rotations_ == 1) {
+    // On the first rotation adjust the max file size so subsequent files after
+    // the first are smaller.
+    SetMaxFileSize(GetRotatingLogSize(max_total_log_size_));
+  } else if (num_rotations_ == (GetNumFiles() - 1)) {
+    // On the next rotation the very first file is going to be deleted. Change
+    // the rotation index so this doesn't happen.
+    SetRotationIndex(GetRotationIndex() - 1);
+  }
+}
+
+size_t CallSessionFileRotatingStream::GetRotatingLogSize(
+    size_t max_total_log_size) {
+  size_t num_rotating_log_files = GetNumRotatingLogFiles(max_total_log_size);
+  size_t rotating_log_size = num_rotating_log_files > 2
+                                 ? kRotatingLogFileDefaultSize
+                                 : max_total_log_size / 4;
+  return rotating_log_size;
+}
+
+size_t CallSessionFileRotatingStream::GetNumRotatingLogFiles(
+    size_t max_total_log_size) {
+  // At minimum have two rotating files. Otherwise split the available log size
+  // evenly across 1MB files.
+  return std::max((size_t)2,
+                  (max_total_log_size / 2) / kRotatingLogFileDefaultSize);
+}
+
+}  // namespace rtc