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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/command_line.h"
      6 
      7 #include <algorithm>
      8 #include <ostream>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/files/file_path.h"
     12 #include "base/logging.h"
     13 #include "base/strings/string_split.h"
     14 #include "base/strings/string_util.h"
     15 #include "base/strings/utf_string_conversions.h"
     16 #include "build/build_config.h"
     17 
     18 #if defined(OS_WIN)
     19 #include <windows.h>
     20 #include <shellapi.h>
     21 #endif
     22 
     23 namespace base {
     24 
     25 CommandLine* CommandLine::current_process_commandline_ = NULL;
     26 
     27 namespace {
     28 
     29 const CommandLine::CharType kSwitchTerminator[] = FILE_PATH_LITERAL("--");
     30 const CommandLine::CharType kSwitchValueSeparator[] = FILE_PATH_LITERAL("=");
     31 
     32 // Since we use a lazy match, make sure that longer versions (like "--") are
     33 // listed before shorter versions (like "-") of similar prefixes.
     34 #if defined(OS_WIN)
     35 // By putting slash last, we can control whether it is treaded as a switch
     36 // value by changing the value of switch_prefix_count to be one less than
     37 // the array size.
     38 const CommandLine::CharType* const kSwitchPrefixes[] = {L"--", L"-", L"/"};
     39 #elif defined(OS_POSIX)
     40 // Unixes don't use slash as a switch.
     41 const CommandLine::CharType* const kSwitchPrefixes[] = {"--", "-"};
     42 #endif
     43 size_t switch_prefix_count = arraysize(kSwitchPrefixes);
     44 
     45 size_t GetSwitchPrefixLength(const CommandLine::StringType& string) {
     46   for (size_t i = 0; i < switch_prefix_count; ++i) {
     47     CommandLine::StringType prefix(kSwitchPrefixes[i]);
     48     if (string.compare(0, prefix.length(), prefix) == 0)
     49       return prefix.length();
     50   }
     51   return 0;
     52 }
     53 
     54 // Fills in |switch_string| and |switch_value| if |string| is a switch.
     55 // This will preserve the input switch prefix in the output |switch_string|.
     56 bool IsSwitch(const CommandLine::StringType& string,
     57               CommandLine::StringType* switch_string,
     58               CommandLine::StringType* switch_value) {
     59   switch_string->clear();
     60   switch_value->clear();
     61   size_t prefix_length = GetSwitchPrefixLength(string);
     62   if (prefix_length == 0 || prefix_length == string.length())
     63     return false;
     64 
     65   const size_t equals_position = string.find(kSwitchValueSeparator);
     66   *switch_string = string.substr(0, equals_position);
     67   if (equals_position != CommandLine::StringType::npos)
     68     *switch_value = string.substr(equals_position + 1);
     69   return true;
     70 }
     71 
     72 // Append switches and arguments, keeping switches before arguments.
     73 void AppendSwitchesAndArguments(CommandLine& command_line,
     74                                 const CommandLine::StringVector& argv) {
     75   bool parse_switches = true;
     76   for (size_t i = 1; i < argv.size(); ++i) {
     77     CommandLine::StringType arg = argv[i];
     78     TrimWhitespace(arg, TRIM_ALL, &arg);
     79 
     80     CommandLine::StringType switch_string;
     81     CommandLine::StringType switch_value;
     82     parse_switches &= (arg != kSwitchTerminator);
     83     if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
     84 #if defined(OS_WIN)
     85       command_line.AppendSwitchNative(UTF16ToASCII(switch_string),
     86                                       switch_value);
     87 #elif defined(OS_POSIX)
     88       command_line.AppendSwitchNative(switch_string, switch_value);
     89 #endif
     90     } else {
     91       command_line.AppendArgNative(arg);
     92     }
     93   }
     94 }
     95 
     96 // Lowercase switches for backwards compatiblity *on Windows*.
     97 std::string LowerASCIIOnWindows(const std::string& string) {
     98 #if defined(OS_WIN)
     99   return StringToLowerASCII(string);
    100 #elif defined(OS_POSIX)
    101   return string;
    102 #endif
    103 }
    104 
    105 
    106 #if defined(OS_WIN)
    107 // Quote a string as necessary for CommandLineToArgvW compatiblity *on Windows*.
    108 std::wstring QuoteForCommandLineToArgvW(const std::wstring& arg) {
    109   // We follow the quoting rules of CommandLineToArgvW.
    110   // http://msdn.microsoft.com/en-us/library/17w5ykft.aspx
    111   if (arg.find_first_of(L" \\\"") == std::wstring::npos) {
    112     // No quoting necessary.
    113     return arg;
    114   }
    115 
    116   std::wstring out;
    117   out.push_back(L'"');
    118   for (size_t i = 0; i < arg.size(); ++i) {
    119     if (arg[i] == '\\') {
    120       // Find the extent of this run of backslashes.
    121       size_t start = i, end = start + 1;
    122       for (; end < arg.size() && arg[end] == '\\'; ++end)
    123         /* empty */;
    124       size_t backslash_count = end - start;
    125 
    126       // Backslashes are escapes only if the run is followed by a double quote.
    127       // Since we also will end the string with a double quote, we escape for
    128       // either a double quote or the end of the string.
    129       if (end == arg.size() || arg[end] == '"') {
    130         // To quote, we need to output 2x as many backslashes.
    131         backslash_count *= 2;
    132       }
    133       for (size_t j = 0; j < backslash_count; ++j)
    134         out.push_back('\\');
    135 
    136       // Advance i to one before the end to balance i++ in loop.
    137       i = end - 1;
    138     } else if (arg[i] == '"') {
    139       out.push_back('\\');
    140       out.push_back('"');
    141     } else {
    142       out.push_back(arg[i]);
    143     }
    144   }
    145   out.push_back('"');
    146 
    147   return out;
    148 }
    149 #endif
    150 
    151 }  // namespace
    152 
    153 CommandLine::CommandLine(NoProgram no_program)
    154     : argv_(1),
    155       begin_args_(1) {
    156 }
    157 
    158 CommandLine::CommandLine(const FilePath& program)
    159     : argv_(1),
    160       begin_args_(1) {
    161   SetProgram(program);
    162 }
    163 
    164 CommandLine::CommandLine(int argc, const CommandLine::CharType* const* argv)
    165     : argv_(1),
    166       begin_args_(1) {
    167   InitFromArgv(argc, argv);
    168 }
    169 
    170 CommandLine::CommandLine(const StringVector& argv)
    171     : argv_(1),
    172       begin_args_(1) {
    173   InitFromArgv(argv);
    174 }
    175 
    176 CommandLine::~CommandLine() {
    177 }
    178 
    179 #if defined(OS_WIN)
    180 // static
    181 void CommandLine::set_slash_is_not_a_switch() {
    182   // The last switch prefix should be slash, so adjust the size to skip it.
    183   DCHECK(wcscmp(kSwitchPrefixes[arraysize(kSwitchPrefixes) - 1], L"/") == 0);
    184   switch_prefix_count = arraysize(kSwitchPrefixes) - 1;
    185 }
    186 #endif
    187 
    188 // static
    189 bool CommandLine::Init(int argc, const char* const* argv) {
    190   if (current_process_commandline_) {
    191     // If this is intentional, Reset() must be called first. If we are using
    192     // the shared build mode, we have to share a single object across multiple
    193     // shared libraries.
    194     return false;
    195   }
    196 
    197   current_process_commandline_ = new CommandLine(NO_PROGRAM);
    198 #if defined(OS_WIN)
    199   current_process_commandline_->ParseFromString(::GetCommandLineW());
    200 #elif defined(OS_POSIX)
    201   current_process_commandline_->InitFromArgv(argc, argv);
    202 #endif
    203 
    204   return true;
    205 }
    206 
    207 // static
    208 void CommandLine::Reset() {
    209   DCHECK(current_process_commandline_);
    210   delete current_process_commandline_;
    211   current_process_commandline_ = NULL;
    212 }
    213 
    214 // static
    215 CommandLine* CommandLine::ForCurrentProcess() {
    216   DCHECK(current_process_commandline_);
    217   return current_process_commandline_;
    218 }
    219 
    220 // static
    221 bool CommandLine::InitializedForCurrentProcess() {
    222   return !!current_process_commandline_;
    223 }
    224 
    225 #if defined(OS_WIN)
    226 // static
    227 CommandLine CommandLine::FromString(const std::wstring& command_line) {
    228   CommandLine cmd(NO_PROGRAM);
    229   cmd.ParseFromString(command_line);
    230   return cmd;
    231 }
    232 #endif
    233 
    234 void CommandLine::InitFromArgv(int argc,
    235                                const CommandLine::CharType* const* argv) {
    236   StringVector new_argv;
    237   for (int i = 0; i < argc; ++i)
    238     new_argv.push_back(argv[i]);
    239   InitFromArgv(new_argv);
    240 }
    241 
    242 void CommandLine::InitFromArgv(const StringVector& argv) {
    243   argv_ = StringVector(1);
    244   switches_.clear();
    245   begin_args_ = 1;
    246   SetProgram(argv.empty() ? FilePath() : FilePath(argv[0]));
    247   AppendSwitchesAndArguments(*this, argv);
    248 }
    249 
    250 CommandLine::StringType CommandLine::GetCommandLineString() const {
    251   StringType string(argv_[0]);
    252 #if defined(OS_WIN)
    253   string = QuoteForCommandLineToArgvW(string);
    254 #endif
    255   StringType params(GetArgumentsString());
    256   if (!params.empty()) {
    257     string.append(StringType(FILE_PATH_LITERAL(" ")));
    258     string.append(params);
    259   }
    260   return string;
    261 }
    262 
    263 CommandLine::StringType CommandLine::GetArgumentsString() const {
    264   StringType params;
    265   // Append switches and arguments.
    266   bool parse_switches = true;
    267   for (size_t i = 1; i < argv_.size(); ++i) {
    268     StringType arg = argv_[i];
    269     StringType switch_string;
    270     StringType switch_value;
    271     parse_switches &= arg != kSwitchTerminator;
    272     if (i > 1)
    273       params.append(StringType(FILE_PATH_LITERAL(" ")));
    274     if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
    275       params.append(switch_string);
    276       if (!switch_value.empty()) {
    277 #if defined(OS_WIN)
    278         switch_value = QuoteForCommandLineToArgvW(switch_value);
    279 #endif
    280         params.append(kSwitchValueSeparator + switch_value);
    281       }
    282     }
    283     else {
    284 #if defined(OS_WIN)
    285       arg = QuoteForCommandLineToArgvW(arg);
    286 #endif
    287       params.append(arg);
    288     }
    289   }
    290   return params;
    291 }
    292 
    293 FilePath CommandLine::GetProgram() const {
    294   return FilePath(argv_[0]);
    295 }
    296 
    297 void CommandLine::SetProgram(const FilePath& program) {
    298   TrimWhitespace(program.value(), TRIM_ALL, &argv_[0]);
    299 }
    300 
    301 bool CommandLine::HasSwitch(const std::string& switch_string) const {
    302   return switches_.find(LowerASCIIOnWindows(switch_string)) != switches_.end();
    303 }
    304 
    305 std::string CommandLine::GetSwitchValueASCII(
    306     const std::string& switch_string) const {
    307   StringType value = GetSwitchValueNative(switch_string);
    308   if (!IsStringASCII(value)) {
    309     DLOG(WARNING) << "Value of switch (" << switch_string << ") must be ASCII.";
    310     return std::string();
    311   }
    312 #if defined(OS_WIN)
    313   return UTF16ToASCII(value);
    314 #else
    315   return value;
    316 #endif
    317 }
    318 
    319 FilePath CommandLine::GetSwitchValuePath(
    320     const std::string& switch_string) const {
    321   return FilePath(GetSwitchValueNative(switch_string));
    322 }
    323 
    324 CommandLine::StringType CommandLine::GetSwitchValueNative(
    325     const std::string& switch_string) const {
    326   SwitchMap::const_iterator result =
    327     switches_.find(LowerASCIIOnWindows(switch_string));
    328   return result == switches_.end() ? StringType() : result->second;
    329 }
    330 
    331 void CommandLine::AppendSwitch(const std::string& switch_string) {
    332   AppendSwitchNative(switch_string, StringType());
    333 }
    334 
    335 void CommandLine::AppendSwitchPath(const std::string& switch_string,
    336                                    const FilePath& path) {
    337   AppendSwitchNative(switch_string, path.value());
    338 }
    339 
    340 void CommandLine::AppendSwitchNative(const std::string& switch_string,
    341                                      const CommandLine::StringType& value) {
    342   std::string switch_key(LowerASCIIOnWindows(switch_string));
    343 #if defined(OS_WIN)
    344   StringType combined_switch_string(ASCIIToWide(switch_key));
    345 #elif defined(OS_POSIX)
    346   StringType combined_switch_string(switch_string);
    347 #endif
    348   size_t prefix_length = GetSwitchPrefixLength(combined_switch_string);
    349   switches_[switch_key.substr(prefix_length)] = value;
    350   // Preserve existing switch prefixes in |argv_|; only append one if necessary.
    351   if (prefix_length == 0)
    352     combined_switch_string = kSwitchPrefixes[0] + combined_switch_string;
    353   if (!value.empty())
    354     combined_switch_string += kSwitchValueSeparator + value;
    355   // Append the switch and update the switches/arguments divider |begin_args_|.
    356   argv_.insert(argv_.begin() + begin_args_++, combined_switch_string);
    357 }
    358 
    359 void CommandLine::AppendSwitchASCII(const std::string& switch_string,
    360                                     const std::string& value_string) {
    361 #if defined(OS_WIN)
    362   AppendSwitchNative(switch_string, ASCIIToWide(value_string));
    363 #elif defined(OS_POSIX)
    364   AppendSwitchNative(switch_string, value_string);
    365 #endif
    366 }
    367 
    368 void CommandLine::CopySwitchesFrom(const CommandLine& source,
    369                                    const char* const switches[],
    370                                    size_t count) {
    371   for (size_t i = 0; i < count; ++i) {
    372     if (source.HasSwitch(switches[i]))
    373       AppendSwitchNative(switches[i], source.GetSwitchValueNative(switches[i]));
    374   }
    375 }
    376 
    377 CommandLine::StringVector CommandLine::GetArgs() const {
    378   // Gather all arguments after the last switch (may include kSwitchTerminator).
    379   StringVector args(argv_.begin() + begin_args_, argv_.end());
    380   // Erase only the first kSwitchTerminator (maybe "--" is a legitimate page?)
    381   StringVector::iterator switch_terminator =
    382       std::find(args.begin(), args.end(), kSwitchTerminator);
    383   if (switch_terminator != args.end())
    384     args.erase(switch_terminator);
    385   return args;
    386 }
    387 
    388 void CommandLine::AppendArg(const std::string& value) {
    389 #if defined(OS_WIN)
    390   DCHECK(IsStringUTF8(value));
    391   AppendArgNative(UTF8ToWide(value));
    392 #elif defined(OS_POSIX)
    393   AppendArgNative(value);
    394 #endif
    395 }
    396 
    397 void CommandLine::AppendArgPath(const FilePath& path) {
    398   AppendArgNative(path.value());
    399 }
    400 
    401 void CommandLine::AppendArgNative(const CommandLine::StringType& value) {
    402   argv_.push_back(value);
    403 }
    404 
    405 void CommandLine::AppendArguments(const CommandLine& other,
    406                                   bool include_program) {
    407   if (include_program)
    408     SetProgram(other.GetProgram());
    409   AppendSwitchesAndArguments(*this, other.argv());
    410 }
    411 
    412 void CommandLine::PrependWrapper(const CommandLine::StringType& wrapper) {
    413   if (wrapper.empty())
    414     return;
    415   // The wrapper may have embedded arguments (like "gdb --args"). In this case,
    416   // we don't pretend to do anything fancy, we just split on spaces.
    417   StringVector wrapper_argv;
    418   SplitString(wrapper, FILE_PATH_LITERAL(' '), &wrapper_argv);
    419   // Prepend the wrapper and update the switches/arguments |begin_args_|.
    420   argv_.insert(argv_.begin(), wrapper_argv.begin(), wrapper_argv.end());
    421   begin_args_ += wrapper_argv.size();
    422 }
    423 
    424 #if defined(OS_WIN)
    425 void CommandLine::ParseFromString(const std::wstring& command_line) {
    426   std::wstring command_line_string;
    427   TrimWhitespace(command_line, TRIM_ALL, &command_line_string);
    428   if (command_line_string.empty())
    429     return;
    430 
    431   int num_args = 0;
    432   wchar_t** args = NULL;
    433   args = ::CommandLineToArgvW(command_line_string.c_str(), &num_args);
    434 
    435   DPLOG_IF(FATAL, !args) << "CommandLineToArgvW failed on command line: "
    436                          << UTF16ToUTF8(command_line);
    437   InitFromArgv(num_args, args);
    438   LocalFree(args);
    439 }
    440 #endif
    441 
    442 }  // namespace base
    443