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      1 //===--- CommentCommandTraits.cpp - Comment command properties --*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "clang/AST/CommentCommandTraits.h"
     11 #include "llvm/ADT/STLExtras.h"
     12 
     13 namespace clang {
     14 namespace comments {
     15 
     16 #include "clang/AST/CommentCommandInfo.inc"
     17 
     18 CommandTraits::CommandTraits(llvm::BumpPtrAllocator &Allocator,
     19                              const CommentOptions &CommentOptions) :
     20     NextID(llvm::array_lengthof(Commands)), Allocator(Allocator) {
     21   registerCommentOptions(CommentOptions);
     22 }
     23 
     24 void CommandTraits::registerCommentOptions(
     25     const CommentOptions &CommentOptions) {
     26   for (CommentOptions::BlockCommandNamesTy::const_iterator
     27            I = CommentOptions.BlockCommandNames.begin(),
     28            E = CommentOptions.BlockCommandNames.end();
     29        I != E; I++) {
     30     registerBlockCommand(*I);
     31   }
     32 }
     33 
     34 const CommandInfo *CommandTraits::getCommandInfoOrNULL(StringRef Name) const {
     35   if (const CommandInfo *Info = getBuiltinCommandInfo(Name))
     36     return Info;
     37   return getRegisteredCommandInfo(Name);
     38 }
     39 
     40 const CommandInfo *CommandTraits::getCommandInfo(unsigned CommandID) const {
     41   if (const CommandInfo *Info = getBuiltinCommandInfo(CommandID))
     42     return Info;
     43   return getRegisteredCommandInfo(CommandID);
     44 }
     45 
     46 const CommandInfo *
     47 CommandTraits::getTypoCorrectCommandInfo(StringRef Typo) const {
     48   // Single-character command impostures, such as \t or \n, should not go
     49   // through the fixit logic.
     50   if (Typo.size() <= 1)
     51     return nullptr;
     52 
     53   // The maximum edit distance we're prepared to accept.
     54   const unsigned MaxEditDistance = 1;
     55 
     56   unsigned BestEditDistance = MaxEditDistance;
     57   SmallVector<const CommandInfo *, 2> BestCommand;
     58 
     59   auto ConsiderCorrection = [&](const CommandInfo *Command) {
     60     StringRef Name = Command->Name;
     61 
     62     unsigned MinPossibleEditDistance = abs((int)Name.size() - (int)Typo.size());
     63     if (MinPossibleEditDistance <= BestEditDistance) {
     64       unsigned EditDistance = Typo.edit_distance(Name, true, BestEditDistance);
     65       if (EditDistance < BestEditDistance) {
     66         BestEditDistance = EditDistance;
     67         BestCommand.clear();
     68       }
     69       if (EditDistance == BestEditDistance)
     70         BestCommand.push_back(Command);
     71     }
     72   };
     73 
     74   for (const auto &Command : Commands)
     75     ConsiderCorrection(&Command);
     76 
     77   for (const auto *Command : RegisteredCommands)
     78     if (!Command->IsUnknownCommand)
     79       ConsiderCorrection(Command);
     80 
     81   return BestCommand.size() == 1 ? BestCommand[0] : nullptr;
     82 }
     83 
     84 CommandInfo *CommandTraits::createCommandInfoWithName(StringRef CommandName) {
     85   char *Name = Allocator.Allocate<char>(CommandName.size() + 1);
     86   memcpy(Name, CommandName.data(), CommandName.size());
     87   Name[CommandName.size()] = '\0';
     88 
     89   // Value-initialize (=zero-initialize in this case) a new CommandInfo.
     90   CommandInfo *Info = new (Allocator) CommandInfo();
     91   Info->Name = Name;
     92   // We only have a limited number of bits to encode command IDs in the
     93   // CommandInfo structure, so the ID numbers can potentially wrap around.
     94   assert((NextID < (1 << CommandInfo::NumCommandIDBits))
     95          && "Too many commands. We have limited bits for the command ID.");
     96   Info->ID = NextID++;
     97 
     98   RegisteredCommands.push_back(Info);
     99 
    100   return Info;
    101 }
    102 
    103 const CommandInfo *CommandTraits::registerUnknownCommand(
    104                                                   StringRef CommandName) {
    105   CommandInfo *Info = createCommandInfoWithName(CommandName);
    106   Info->IsUnknownCommand = true;
    107   return Info;
    108 }
    109 
    110 const CommandInfo *CommandTraits::registerBlockCommand(StringRef CommandName) {
    111   CommandInfo *Info = createCommandInfoWithName(CommandName);
    112   Info->IsBlockCommand = true;
    113   return Info;
    114 }
    115 
    116 const CommandInfo *CommandTraits::getBuiltinCommandInfo(
    117                                                   unsigned CommandID) {
    118   if (CommandID < llvm::array_lengthof(Commands))
    119     return &Commands[CommandID];
    120   return nullptr;
    121 }
    122 
    123 const CommandInfo *CommandTraits::getRegisteredCommandInfo(
    124                                                   StringRef Name) const {
    125   for (unsigned i = 0, e = RegisteredCommands.size(); i != e; ++i) {
    126     if (RegisteredCommands[i]->Name == Name)
    127       return RegisteredCommands[i];
    128   }
    129   return nullptr;
    130 }
    131 
    132 const CommandInfo *CommandTraits::getRegisteredCommandInfo(
    133                                                   unsigned CommandID) const {
    134   return RegisteredCommands[CommandID - llvm::array_lengthof(Commands)];
    135 }
    136 
    137 } // end namespace comments
    138 } // end namespace clang
    139 
    140