toolkit/xre/AssembleCmdLine.h

   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 https://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_AssembleCmdLine_h
   8 #define mozilla_AssembleCmdLine_h
   9
  10 #if defined(XP_WIN)
  11
  12 #  include "mozilla/UniquePtr.h"
  13
  14 #  include <stdlib.h>
  15 #  include <windows.h>
  16
  17 #  ifdef MOZILLA_INTERNAL_API
  18 #    include "nsString.h"
  19 #  endif  // MOZILLA_INTERNAL_API
  20
  21 namespace mozilla {
  22
  23 // Out param `aWideCmdLine` must be free()d by the caller.
  24 inline int assembleCmdLine(const char* const* aArgv, wchar_t** aWideCmdLine,
  25                            UINT aCodePage) {
  26   const char* const* arg;
  27   char* p;
  28   const char* q;
  29   char* cmdLine;
  30   int cmdLineSize;
  31   int numBackslashes;
  32   int i;
  33   int argNeedQuotes;
  34
  35   /*
  36    * Find out how large the command line buffer should be.
  37    */
  38   cmdLineSize = 0;
  39   for (arg = aArgv; *arg; ++arg) {
  40     /*
  41      * \ and " need to be escaped by a \.  In the worst case,
  42      * every character is a \ or ", so the string of length
  43      * may double.  If we quote an argument, that needs two ".
  44      * Finally, we need a space between arguments, and
  45      * a null byte at the end of command line.
  46      */
  47     cmdLineSize += 2 * strlen(*arg) /* \ and " need to be escaped */
  48                    + 2              /* we quote every argument */
  49                    + 1;             /* space in between, or final null */
  50   }
  51   p = cmdLine = (char*)malloc(cmdLineSize * sizeof(char));
  52   if (!p) {
  53     return -1;
  54   }
  55
  56   for (arg = aArgv; *arg; ++arg) {
  57     /* Add a space to separates the arguments */
  58     if (arg != aArgv) {
  59       *p++ = ' ';
  60     }
  61     q = *arg;
  62     numBackslashes = 0;
  63     argNeedQuotes = 0;
  64
  65     /*
  66      * If the argument is empty or contains white space, it needs to
  67      * be quoted.
  68      */
  69     if (**arg == '\0' || strpbrk(*arg, " \f\n\r\t\v")) {
  70       argNeedQuotes = 1;
  71     }
  72
  73     if (argNeedQuotes) {
  74       *p++ = '"';
  75     }
  76     while (*q) {
  77       if (*q == '\\') {
  78         numBackslashes++;
  79         q++;
  80       } else if (*q == '"') {
  81         if (numBackslashes) {
  82           /*
  83            * Double the backslashes since they are followed
  84            * by a quote
  85            */
  86           for (i = 0; i < 2 * numBackslashes; i++) {
  87             *p++ = '\\';
  88           }
  89           numBackslashes = 0;
  90         }
  91         /* To escape the quote */
  92         *p++ = '\\';
  93         *p++ = *q++;
  94       } else {
  95         if (numBackslashes) {
  96           /*
  97            * Backslashes are not followed by a quote, so
  98            * don't need to double the backslashes.
  99            */
 100           for (i = 0; i < numBackslashes; i++) {
 101             *p++ = '\\';
 102           }
 103           numBackslashes = 0;
 104         }
 105         *p++ = *q++;
 106       }
 107     }
 108
 109     /* Now we are at the end of this argument */
 110     if (numBackslashes) {
 111       /*
 112        * Double the backslashes if we have a quote string
 113        * delimiter at the end.
 114        */
 115       if (argNeedQuotes) {
 116         numBackslashes *= 2;
 117       }
 118       for (i = 0; i < numBackslashes; i++) {
 119         *p++ = '\\';
 120       }
 121     }
 122     if (argNeedQuotes) {
 123       *p++ = '"';
 124     }
 125   }
 126
 127   *p = '\0';
 128   int numChars = MultiByteToWideChar(aCodePage, 0, cmdLine, -1, nullptr, 0);
 129   *aWideCmdLine = (wchar_t*)malloc(numChars * sizeof(wchar_t));
 130   MultiByteToWideChar(aCodePage, 0, cmdLine, -1, *aWideCmdLine, numChars);
 131   free(cmdLine);
 132   return 0;
 133 }
 134
 135 }  // namespace mozilla
 136
 137 #endif  // defined(XP_WIN)
 138
 139 #endif  // mozilla_AssembleCmdLine_h