Mojo Log service and a thread-safe client library.

services/log/log_impl.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "services/log/log_impl.h"
+
+#include <stdio.h>
+
+#include "mojo/public/cpp/application/application_connection.h"
+#include "mojo/public/cpp/bindings/interface_request.h"
+#include "mojo/public/cpp/system/functions.h"
+#include "mojo/services/log/interfaces/entry.mojom.h"
+
+namespace mojo {
+namespace log {
+
+namespace {
+std::string LogLevelToString(int32_t log_level) {
+  if (log_level <= kLogLevelVerbose - 3)
+    return "VERBOSE4+";
+  switch (log_level) {
+    case kLogLevelVerbose - 2:
+      return "VERBOSE3";
+    case kLogLevelVerbose - 1:
+      return "VERBOSE2";
+    case kLogLevelVerbose:
+      return "VERBOSE1";
+    case kLogLevelInfo:
+      return "INFO";
+    case kLogLevelWarning:
+      return "WARNING";
+    case kLogLevelError:
+      return "ERROR";
+  }
+  return "FATAL";
+}
+}  // namespace
+
+LogImpl::LogImpl(const std::string& remote_url, InterfaceRequest<Log> request)
+    : remote_url_(remote_url), binding_(this, request.Pass()) {}
+
+LogImpl::~LogImpl() {}
+
+// static
+void LogImpl::Create(ApplicationConnection* connection,
+                     InterfaceRequest<Log> request) {
+  MOJO_DCHECK(connection);
+  const std::string& remote_url = connection->GetRemoteApplicationURL();
+  if (remote_url.empty()) {
+    MOJO_LOG(ERROR) << "No remote URL";
+    return;
+  }
+
+  new LogImpl(remote_url, request.Pass());
+}
+
+void LogImpl::AddEntry(EntryPtr entry) {
+  MOJO_DCHECK(entry);
+
+  int64_t server_timestamp = GetTimeTicksNow();
+
+  MOJO_DLOG_IF(WARNING, entry->metadata)
+      << "Got AddEntry() with metadata (will discard)";
+
+  entry->metadata = EntryMetadata::New();
+  entry->metadata->server_timestamp = server_timestamp;
+  entry->metadata->source = remote_url_;
+
+  // In order to keep LogImpl thread-safe (for the future), we should only print
+  // one thing here (otherwise, it could interleave with other prints).
+  fprintf(stderr, "%s\n", FormatEntry(entry).c_str());
+}
+
+std::string LogImpl::FormatEntry(const EntryPtr& entry) {
+  std::string rv = "<";
+  rv += remote_url_;
+  rv += "> [";
+  rv += LogLevelToString(entry->log_level);
+  rv += "] ";
+  if (entry->source_file) {
+    rv += entry->source_file.To<std::string>();
+    if (entry->source_line) {
+      char line_str[20];
+      int chars_written = snprintf(line_str, sizeof(line_str), ":%u",
+                                   static_cast<uint32_t>(entry->source_line));
+      MOJO_DCHECK(chars_written > 0);
+      MOJO_DCHECK(chars_written <= static_cast<int>(sizeof(line_str) - 1));
+
+      rv += line_str;
+    }
+    rv += ": ";
+  }
+  rv += entry->message ? entry->message.To<std::string>() : "<no message>";
+  return rv;
+}
+
+}  // namespace log
+}  // namespace mojo