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