xpcom/base/LogCommandLineHandler.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "LogCommandLineHandler.h"
   8
   9 #include "mozilla/Tokenizer.h"
  10 #include "nsDebug.h"
  11
  12 namespace mozilla {
  13
  14 void LoggingHandleCommandLineArgs(
  15     int argc, char const* const* argv,
  16     std::function<void(nsACString const&)> const& consumer) {
  17   // Keeps the name of a pending env var (MOZ_LOG or MOZ_LOG_FILE) that
  18   // we expect to get a value for in the next iterated arg.
  19   // Used for the `-MOZ_LOG <modules>` form of argument.
  20   nsAutoCString env;
  21
  22   auto const names = {"MOZ_LOG"_ns, "MOZ_LOG_FILE"_ns};
  23
  24   for (int arg = 1; arg < argc; ++arg) {
  25     Tokenizer p(argv[arg]);
  26
  27     if (!env.IsEmpty() && p.CheckChar('-')) {
  28       NS_WARNING(
  29           "Expects value after -MOZ_LOG(_FILE) argument, but another argument "
  30           "found");
  31
  32       // We only expect values for the pending env var, start over
  33       p.Rollback();
  34       env.Truncate();
  35     }
  36
  37     if (env.IsEmpty()) {
  38       if (!p.CheckChar('-')) {
  39         continue;
  40       }
  41       // We accept `-MOZ_LOG` as well as `--MOZ_LOG`.
  42       Unused << p.CheckChar('-');
  43
  44       for (auto const& name : names) {
  45         if (!p.CheckWord(name)) {
  46           continue;
  47         }
  48
  49         env.Assign(name);
  50         env.Append('=');
  51         break;
  52       }
  53
  54       if (env.IsEmpty()) {
  55         // An unknonwn argument, ignore.
  56         continue;
  57       }
  58
  59       // We accept `-MOZ_LOG <modules>` as well as `-MOZ_LOG=<modules>`.
  60
  61       if (p.CheckEOF()) {
  62         // We have a lone `-MOZ_LOG` arg, the next arg is expected to be
  63         // the value, |env| is now prepared as `MOZ_LOG=`.
  64         continue;
  65       }
  66
  67       if (!p.CheckChar('=')) {
  68         // There is a character after the arg name and it's not '=',
  69         // ignore this argument.
  70         NS_WARNING("-MOZ_LOG(_FILE) argument not in a proper form");
  71
  72         env.Truncate();
  73         continue;
  74       }
  75     }
  76
  77     // This can be non-empty from previous iteration or in this iteration.
  78     if (!env.IsEmpty()) {
  79       nsDependentCSubstring value;
  80       Unused << p.ReadUntil(Tokenizer::Token::EndOfFile(), value);
  81       env.Append(value);
  82
  83       consumer(env);
  84
  85       env.Truncate();
  86     }
  87   }
  88 }
  89
  90 }  // namespace mozilla