C++ SmallString::back方法代码示例

/// Determine whether the given text matches a property name.
static bool textMatchesPropertyName(StringRef text,
                                    const InheritedNameSet *allPropertyNames) {
  if (!allPropertyNames) return false;

  SmallString<16> localScratch;
  auto name = camel_case::toLowercaseWord(text, localScratch);

  // A property with exactly this name.
  if (allPropertyNames->contains(name)) return true;

  // From here on, we'll be working with scratch space.
  if (name.data() != localScratch.data())
    localScratch = name;

  if (localScratch.back() == 'y') {
    // If the last letter is a 'y', try 'ies'.
    localScratch.pop_back();
    localScratch += "ies";
    if (allPropertyNames->contains(localScratch)) return true;
  } else {
    // Otherwise, add an 's' and try again.
    localScratch += 's';
    if (allPropertyNames->contains(localScratch)) return true;

    // Alternatively, try to add 'es'.
    localScratch.pop_back();
    localScratch += "es";
    if (allPropertyNames->contains(localScratch)) return true;
  }

  return false;
}

/// \brief Find the end of the word starting at the given offset
/// within a string.
///
/// \returns the index pointing one character past the end of the
/// word.
static unsigned findEndOfWord(unsigned Start, StringRef Str,
                              unsigned Length, unsigned Column,
                              unsigned Columns) {
  assert(Start < Str.size() && "Invalid start position!");
  unsigned End = Start + 1;

  // If we are already at the end of the string, take that as the word.
  if (End == Str.size())
    return End;

  // Determine if the start of the string is actually opening
  // punctuation, e.g., a quote or parentheses.
  char EndPunct = findMatchingPunctuation(Str[Start]);
  if (!EndPunct) {
    // This is a normal word. Just find the first space character.
    while (End < Length && !isspace(Str[End]))
      ++End;
    return End;
  }

  // We have the start of a balanced punctuation sequence (quotes,
  // parentheses, etc.). Determine the full sequence is.
  SmallString<16> PunctuationEndStack;
  PunctuationEndStack.push_back(EndPunct);
  while (End < Length && !PunctuationEndStack.empty()) {
    if (Str[End] == PunctuationEndStack.back())
      PunctuationEndStack.pop_back();
    else if (char SubEndPunct = findMatchingPunctuation(Str[End]))
      PunctuationEndStack.push_back(SubEndPunct);

    ++End;
  }

  // Find the first space character after the punctuation ended.
  while (End < Length && !isspace(Str[End]))
    ++End;

  unsigned PunctWordLength = End - Start;
  if (// If the word fits on this line
      Column + PunctWordLength <= Columns ||
      // ... or the word is "short enough" to take up the next line
      // without too much ugly white space
      PunctWordLength < Columns/3)
    return End; // Take the whole thing as a single "word".

  // The whole quoted/parenthesized string is too long to print as a
  // single "word". Instead, find the "word" that starts just after
  // the punctuation and use that end-point instead. This will recurse
  // until it finds something small enough to consider a word.
  return findEndOfWord(Start + 1, Str, Length, Column + 1, Columns);
}

static StringRef omitNeedlessWords(StringRef name,
                                   OmissionTypeName typeName,
                                   NameRole role,
                                   const InheritedNameSet *allPropertyNames,
                                   StringScratchSpace &scratch) {
  // If we have no name or no type name, there is nothing to do.
  if (name.empty() || typeName.empty()) return name;

  // Get the camel-case words in the name and type name.
  auto nameWords = camel_case::getWords(name);
  auto typeWords = camel_case::getWords(typeName.Name);

  // Match the last words in the type name to the last words in the
  // name.
  auto nameWordRevIter = nameWords.rbegin(),
    nameWordRevIterBegin = nameWordRevIter,
    firstMatchingNameWordRevIter = nameWordRevIter,
    nameWordRevIterEnd = nameWords.rend();
  auto typeWordRevIter = typeWords.rbegin(),
    typeWordRevIterEnd = typeWords.rend();


  bool anyMatches = false;
  auto matched = [&] {
    if (anyMatches) return;

    anyMatches = true;
    firstMatchingNameWordRevIter = nameWordRevIter;
  };

  while (nameWordRevIter != nameWordRevIterEnd &&
         typeWordRevIter != typeWordRevIterEnd) {
    // If the names match, continue.
    auto nameWord = *nameWordRevIter;
    if (matchNameWordToTypeWord(nameWord, *typeWordRevIter)) {
      matched();
      ++nameWordRevIter;
      ++typeWordRevIter;
      continue;
    }

    // Special case: "Indexes" and "Indices" in the name match
    // "IndexSet" in the type.
    if ((matchNameWordToTypeWord(nameWord, "Indexes") ||
         matchNameWordToTypeWord(nameWord, "Indices")) &&
        *typeWordRevIter == "Set") {
      auto nextTypeWordRevIter = typeWordRevIter;
      ++nextTypeWordRevIter;
      if (nextTypeWordRevIter != typeWordRevIterEnd &&
          matchNameWordToTypeWord("Index", *nextTypeWordRevIter)) {
        matched();
        ++nameWordRevIter;
        typeWordRevIter = nextTypeWordRevIter;
        ++typeWordRevIter;
        continue;
      }
    }

    // Special case: "Index" in the name matches "Int" or "Integer" in the type.
    if (matchNameWordToTypeWord(nameWord, "Index") &&
        (matchNameWordToTypeWord("Int", *typeWordRevIter) ||
         matchNameWordToTypeWord("Integer", *typeWordRevIter))) {
      matched();
      ++nameWordRevIter;
      ++typeWordRevIter;
      continue;
    }

    // Special case: if the word in the name ends in 's', and we have
    // a collection element type, see if this is a plural.
    if (!typeName.CollectionElement.empty() && nameWord.size() > 2 &&
        nameWord.back() == 's' && role != NameRole::BaseNameSelf) {
      // Check <element name>s.
      auto shortenedNameWord
        = name.substr(0, nameWordRevIter.base().getPosition()-1);
      auto newShortenedNameWord
        = omitNeedlessWords(shortenedNameWord, typeName.CollectionElement,
                            NameRole::Partial, allPropertyNames, scratch);
      if (shortenedNameWord != newShortenedNameWord) {
        matched();
        unsigned targetSize = newShortenedNameWord.size();
        while (nameWordRevIter.base().getPosition() > targetSize)
          ++nameWordRevIter;
        continue;
      }
    }

    // If this is a skippable suffix, skip it and keep looking.
    if (nameWordRevIter == nameWordRevIterBegin) {
      if (auto withoutSuffix = skipTypeSuffix(typeName.Name)) {
        typeName.Name = *withoutSuffix;
        typeWords = camel_case::getWords(typeName.Name);
        typeWordRevIter = typeWords.rbegin();
        typeWordRevIterEnd = typeWords.rend();
        continue;
      }
    }

    // If we're matching the base name of a method against the type of
    // 'Self', and we haven't matched anything yet, skip over words in
//.........这里部分代码省略.........

/// DoFrameworkLookup - Do a lookup of the specified file in the current
/// DirectoryLookup, which is a framework directory.
const FileEntry *DirectoryLookup::DoFrameworkLookup(
    StringRef Filename,
    HeaderSearch &HS,
    SmallVectorImpl<char> *SearchPath,
    SmallVectorImpl<char> *RelativePath,
    ModuleMap::KnownHeader *SuggestedModule,
    bool &InUserSpecifiedSystemFramework) const
{
  FileManager &FileMgr = HS.getFileMgr();

  // Framework names must have a '/' in the filename.
  size_t SlashPos = Filename.find('/');
  if (SlashPos == StringRef::npos) return nullptr;

  // Find out if this is the home for the specified framework, by checking
  // HeaderSearch.  Possible answers are yes/no and unknown.
  HeaderSearch::FrameworkCacheEntry &CacheEntry =
    HS.LookupFrameworkCache(Filename.substr(0, SlashPos));

  // If it is known and in some other directory, fail.
  if (CacheEntry.Directory && CacheEntry.Directory != getFrameworkDir())
    return nullptr;

  // Otherwise, construct the path to this framework dir.

  // FrameworkName = "/System/Library/Frameworks/"
  SmallString<1024> FrameworkName;
  FrameworkName += getFrameworkDir()->getName();
  if (FrameworkName.empty() || FrameworkName.back() != '/')
    FrameworkName.push_back('/');

  // FrameworkName = "/System/Library/Frameworks/Cocoa"
  StringRef ModuleName(Filename.begin(), SlashPos);
  FrameworkName += ModuleName;

  // FrameworkName = "/System/Library/Frameworks/Cocoa.framework/"
  FrameworkName += ".framework/";

  // If the cache entry was unresolved, populate it now.
  if (!CacheEntry.Directory) {
    HS.IncrementFrameworkLookupCount();

    // If the framework dir doesn't exist, we fail.
    const DirectoryEntry *Dir = FileMgr.getDirectory(FrameworkName.str());
    if (!Dir) return nullptr;

    // Otherwise, if it does, remember that this is the right direntry for this
    // framework.
    CacheEntry.Directory = getFrameworkDir();

    // If this is a user search directory, check if the framework has been
    // user-specified as a system framework.
    if (getDirCharacteristic() == SrcMgr::C_User) {
      SmallString<1024> SystemFrameworkMarker(FrameworkName);
      SystemFrameworkMarker += ".system_framework";
      if (llvm::sys::fs::exists(SystemFrameworkMarker.str())) {
        CacheEntry.IsUserSpecifiedSystemFramework = true;
      }
    }
  }

  // Set the 'user-specified system framework' flag.
  InUserSpecifiedSystemFramework = CacheEntry.IsUserSpecifiedSystemFramework;

  if (RelativePath) {
    RelativePath->clear();
    RelativePath->append(Filename.begin()+SlashPos+1, Filename.end());
  }

  // Check "/System/Library/Frameworks/Cocoa.framework/Headers/file.h"
  unsigned OrigSize = FrameworkName.size();

  FrameworkName += "Headers/";

  if (SearchPath) {
    SearchPath->clear();
    // Without trailing '/'.
    SearchPath->append(FrameworkName.begin(), FrameworkName.end()-1);
  }

  FrameworkName.append(Filename.begin()+SlashPos+1, Filename.end());
  const FileEntry *FE = FileMgr.getFile(FrameworkName.str(),
                                        /*openFile=*/!SuggestedModule);
  if (!FE) {
    // Check "/System/Library/Frameworks/Cocoa.framework/PrivateHeaders/file.h"
    const char *Private = "Private";
    FrameworkName.insert(FrameworkName.begin()+OrigSize, Private,
                         Private+strlen(Private));
    if (SearchPath)
      SearchPath->insert(SearchPath->begin()+OrigSize, Private,
                         Private+strlen(Private));

    FE = FileMgr.getFile(FrameworkName.str(), /*openFile=*/!SuggestedModule);
  }

  // If we found the header and are allowed to suggest a module, do so now.
  if (FE && SuggestedModule) {
    // Find the framework in which this header occurs.
//.........这里部分代码省略.........

/// DoFrameworkLookup - Do a lookup of the specified file in the current
/// DirectoryLookup, which is a framework directory.
const FileEntry *DirectoryLookup::DoFrameworkLookup(
    StringRef Filename,
    HeaderSearch &HS,
    SmallVectorImpl<char> *SearchPath,
    SmallVectorImpl<char> *RelativePath,
    Module **SuggestedModule,
    bool &InUserSpecifiedSystemFramework) const
{
  FileManager &FileMgr = HS.getFileMgr();

  // Framework names must have a '/' in the filename.
  size_t SlashPos = Filename.find('/');
  if (SlashPos == StringRef::npos) return 0;

  // Find out if this is the home for the specified framework, by checking
  // HeaderSearch.  Possible answers are yes/no and unknown.
  HeaderSearch::FrameworkCacheEntry &CacheEntry =
    HS.LookupFrameworkCache(Filename.substr(0, SlashPos));

  // If it is known and in some other directory, fail.
  if (CacheEntry.Directory && CacheEntry.Directory != getFrameworkDir())
    return 0;

  // Otherwise, construct the path to this framework dir.

  // FrameworkName = "/System/Library/Frameworks/"
  SmallString<1024> FrameworkName;
  FrameworkName += getFrameworkDir()->getName();
  if (FrameworkName.empty() || FrameworkName.back() != '/')
    FrameworkName.push_back('/');

  // FrameworkName = "/System/Library/Frameworks/Cocoa"
  StringRef ModuleName(Filename.begin(), SlashPos);
  FrameworkName += ModuleName;

  // FrameworkName = "/System/Library/Frameworks/Cocoa.framework/"
  FrameworkName += ".framework/";

  // If the cache entry was unresolved, populate it now.
  if (CacheEntry.Directory == 0) {
    HS.IncrementFrameworkLookupCount();

    // If the framework dir doesn't exist, we fail.
    const DirectoryEntry *Dir = FileMgr.getDirectory(FrameworkName.str());
    if (Dir == 0) return 0;

    // Otherwise, if it does, remember that this is the right direntry for this
    // framework.
    CacheEntry.Directory = getFrameworkDir();

    // If this is a user search directory, check if the framework has been
    // user-specified as a system framework.
    if (getDirCharacteristic() == SrcMgr::C_User) {
      SmallString<1024> SystemFrameworkMarker(FrameworkName);
      SystemFrameworkMarker += ".system_framework";
      if (llvm::sys::fs::exists(SystemFrameworkMarker.str())) {
        CacheEntry.IsUserSpecifiedSystemFramework = true;
      }
    }
  }

  // Set the 'user-specified system framework' flag.
  InUserSpecifiedSystemFramework = CacheEntry.IsUserSpecifiedSystemFramework;

  if (RelativePath != NULL) {
    RelativePath->clear();
    RelativePath->append(Filename.begin()+SlashPos+1, Filename.end());
  }

  // If we're allowed to look for modules, try to load or create the module
  // corresponding to this framework.
  Module *Module = 0;
  if (SuggestedModule) {
    if (const DirectoryEntry *FrameworkDir
                                        = FileMgr.getDirectory(FrameworkName)) {
      bool IsSystem = getDirCharacteristic() != SrcMgr::C_User;
      Module = HS.loadFrameworkModule(ModuleName, FrameworkDir, IsSystem);
    }
  }
  
  // Check "/System/Library/Frameworks/Cocoa.framework/Headers/file.h"
  unsigned OrigSize = FrameworkName.size();

  FrameworkName += "Headers/";

  if (SearchPath != NULL) {
    SearchPath->clear();
    // Without trailing '/'.
    SearchPath->append(FrameworkName.begin(), FrameworkName.end()-1);
  }

  // Determine whether this is the module we're building or not.
  bool AutomaticImport = Module;  
  FrameworkName.append(Filename.begin()+SlashPos+1, Filename.end());
  if (const FileEntry *FE = FileMgr.getFile(FrameworkName.str(),
                                            /*openFile=*/!AutomaticImport)) {
    if (AutomaticImport)
      *SuggestedModule = HS.findModuleForHeader(FE);
//.........这里部分代码省略.........

/// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of
/// tokens into the literal string token that should be produced by the C #
/// preprocessor operator.  If Charify is true, then it should be turned into
/// a character literal for the Microsoft charize (#@) extension.
///
Token MacroArgs::StringifyArgument(const Token *ArgToks,
                                   Preprocessor &PP, bool Charify,
                                   SourceLocation ExpansionLocStart,
                                   SourceLocation ExpansionLocEnd) {
  Token Tok;
  Tok.startToken();
  Tok.setKind(Charify ? tok::char_constant : tok::string_literal);

  const Token *ArgTokStart = ArgToks;

  // Stringify all the tokens.
  SmallString<128> Result;
  Result += "\"";

  bool isFirst = true;
  for (; ArgToks->isNot(tok::eof); ++ArgToks) {
    const Token &Tok = *ArgToks;
    if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine()))
      Result += ' ';
    isFirst = false;

    // If this is a string or character constant, escape the token as specified
    // by 6.10.3.2p2.
    if (tok::isStringLiteral(Tok.getKind()) || // "foo", u8R"x(foo)x"_bar, etc.
        Tok.is(tok::char_constant) ||          // 'x'
        Tok.is(tok::wide_char_constant) ||     // L'x'.
        Tok.is(tok::utf8_char_constant) ||     // u8'x'.
        Tok.is(tok::utf16_char_constant) ||    // u'x'.
        Tok.is(tok::utf32_char_constant)) {    // U'x'.
      bool Invalid = false;
      std::string TokStr = PP.getSpelling(Tok, &Invalid);
      if (!Invalid) {
        std::string Str = Lexer::Stringify(TokStr);
        Result.append(Str.begin(), Str.end());
      }
    } else if (Tok.is(tok::code_completion)) {
      PP.CodeCompleteNaturalLanguage();
    } else {
      // Otherwise, just append the token.  Do some gymnastics to get the token
      // in place and avoid copies where possible.
      unsigned CurStrLen = Result.size();
      Result.resize(CurStrLen+Tok.getLength());
      const char *BufPtr = Result.data() + CurStrLen;
      bool Invalid = false;
      unsigned ActualTokLen = PP.getSpelling(Tok, BufPtr, &Invalid);

      if (!Invalid) {
        // If getSpelling returned a pointer to an already uniqued version of
        // the string instead of filling in BufPtr, memcpy it onto our string.
        if (ActualTokLen && BufPtr != &Result[CurStrLen])
          memcpy(&Result[CurStrLen], BufPtr, ActualTokLen);

        // If the token was dirty, the spelling may be shorter than the token.
        if (ActualTokLen != Tok.getLength())
          Result.resize(CurStrLen+ActualTokLen);
      }
    }
  }

  // If the last character of the string is a \, and if it isn't escaped, this
  // is an invalid string literal, diagnose it as specified in C99.
  if (Result.back() == '\\') {
    // Count the number of consecutive \ characters.  If even, then they are
    // just escaped backslashes, otherwise it's an error.
    unsigned FirstNonSlash = Result.size()-2;
    // Guaranteed to find the starting " if nothing else.
    while (Result[FirstNonSlash] == '\\')
      --FirstNonSlash;
    if ((Result.size()-1-FirstNonSlash) & 1) {
      // Diagnose errors for things like: #define F(X) #X   /   F(\)
      PP.Diag(ArgToks[-1], diag::pp_invalid_string_literal);
      Result.pop_back();  // remove one of the \'s.
    }
  }
  Result += '"';

  // If this is the charify operation and the result is not a legal character
  // constant, diagnose it.
  if (Charify) {
    // First step, turn double quotes into single quotes:
    Result[0] = '\'';
    Result[Result.size()-1] = '\'';

    // Check for bogus character.
    bool isBad = false;
    if (Result.size() == 3)
      isBad = Result[1] == '\'';   // ''' is not legal. '\' already fixed above.
    else
      isBad = (Result.size() != 4 || Result[1] != '\\');  // Not '\x'

    if (isBad) {
      PP.Diag(ArgTokStart[0], diag::err_invalid_character_to_charify);
      Result = "' '";  // Use something arbitrary, but legal.
    }
  }
//.........这里部分代码省略.........