path: root/include/clang/Basic/SourceManager.h

//===--- SourceManager.h - Track and cache source files ---------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file defines the SourceManager interface.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_SOURCEMANAGER_H
#define LLVM_CLANG_SOURCEMANAGER_H

#include "clang/Basic/SourceLocation.h"
#include "llvm/Support/Allocator.h"
#include "llvm/System/DataTypes.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/DenseMap.h"
#include <vector>
#include <cassert>

namespace llvm {
class MemoryBuffer;
class StringRef;
}

namespace clang {

class Diagnostic;
class SourceManager;
class FileManager;
class FileEntry;
class LineTableInfo;
  
/// SrcMgr - Public enums and private classes that are part of the
/// SourceManager implementation.
///
namespace SrcMgr {
  /// CharacteristicKind - This is used to represent whether a file or directory
  /// holds normal user code, system code, or system code which is implicitly
  /// 'extern "C"' in C++ mode.  Entire directories can be tagged with this
  /// (this is maintained by DirectoryLookup and friends) as can specific
  /// FileIDInfos when a #pragma system_header is seen or various other cases.
  ///
  enum CharacteristicKind {
    C_User, C_System, C_ExternCSystem
  };

  /// ContentCache - One instance of this struct is kept for every file
  /// loaded or used.  This object owns the MemoryBuffer object.
  class ContentCache {
    enum CCFlags {
      /// \brief Whether the buffer is invalid.
      InvalidFlag = 0x01,
      /// \brief Whether the buffer should not be freed on destruction.
      DoNotFreeFlag = 0x02
    };
    
    /// Buffer - The actual buffer containing the characters from the input
    /// file.  This is owned by the ContentCache object.
    /// The bits indicate indicates whether the buffer is invalid.
    mutable llvm::PointerIntPair<const llvm::MemoryBuffer *, 2> Buffer;

  public:
    /// Reference to the file entry.  This reference does not own
    /// the FileEntry object.  It is possible for this to be NULL if
    /// the ContentCache encapsulates an imaginary text buffer.
    const FileEntry *Entry;

    /// SourceLineCache - A bump pointer allocated array of offsets for each
    /// source line.  This is lazily computed.  This is owned by the
    /// SourceManager BumpPointerAllocator object.
    unsigned *SourceLineCache;

    /// NumLines - The number of lines in this ContentCache.  This is only valid
    /// if SourceLineCache is non-null.
    unsigned NumLines;

    /// getBuffer - Returns the memory buffer for the associated content.
    ///
    /// \param Diag Object through which diagnostics will be emitted it the
    /// buffer cannot be retrieved.
    /// 
    /// \param Loc If specified, is the location that invalid file diagnostics
    ///     will be emitted at.
    ///
    /// \param Invalid If non-NULL, will be set \c true if an error occurred.
    const llvm::MemoryBuffer *getBuffer(Diagnostic &Diag,
                                        const SourceManager &SM,
                                        SourceLocation Loc = SourceLocation(),
                                        bool *Invalid = 0) const;

    /// getSize - Returns the size of the content encapsulated by this
    ///  ContentCache. This can be the size of the source file or the size of an
    ///  arbitrary scratch buffer.  If the ContentCache encapsulates a source
    ///  file this size is retrieved from the file's FileEntry.
    unsigned getSize() const;

    /// getSizeBytesMapped - Returns the number of bytes actually mapped for
    ///  this ContentCache.  This can be 0 if the MemBuffer was not actually
    ///  instantiated.
    unsigned getSizeBytesMapped() const;

    void setBuffer(const llvm::MemoryBuffer *B) {
      assert(!Buffer.getPointer() && "MemoryBuffer already set.");
      Buffer.setPointer(B);
      Buffer.setInt(false);
    }
    
    /// \brief Get the underlying buffer, returning NULL if the buffer is not
    /// yet available.
    const llvm::MemoryBuffer *getRawBuffer() const {
      return Buffer.getPointer();
    }

    /// \brief Replace the existing buffer (which will be deleted)
    /// with the given buffer.
    void replaceBuffer(const llvm::MemoryBuffer *B, bool DoNotFree = false);

    /// \brief Determine whether the buffer itself is invalid.
    bool isBufferInvalid() const {
      return Buffer.getInt() & InvalidFlag;
    }
    
    /// \brief Determine whether the buffer should be freed.
    bool shouldFreeBuffer() const {
      return (Buffer.getInt() & DoNotFreeFlag) == 0;
    }
    
    ContentCache(const FileEntry *Ent = 0)
      : Buffer(0, false), Entry(Ent), SourceLineCache(0), NumLines(0) {}

    ~ContentCache();

    /// The copy ctor does not allow copies where source object has either
    ///  a non-NULL Buffer or SourceLineCache.  Ownership of allocated memory
    ///  is not transfered, so this is a logical error.
    ContentCache(const ContentCache &RHS) 
      : Buffer(0, false), SourceLineCache(0) 
    {
      Entry = RHS.Entry;

      assert (RHS.Buffer.getPointer() == 0 && RHS.SourceLineCache == 0
              && "Passed ContentCache object cannot own a buffer.");

      NumLines = RHS.NumLines;
    }

  private:
    // Disable assignments.
    ContentCache &operator=(const ContentCache& RHS);
  };

  /// FileInfo - Information about a FileID, basically just the logical file
  /// that it represents and include stack information.
  ///
  /// Each FileInfo has include stack information, indicating where it came
  /// from.  This information encodes the #include chain that a token was
  /// instantiated from.  The main include file has an invalid IncludeLoc.
  ///
  /// FileInfos contain a "ContentCache *", with the contents of the file.
  ///
  class FileInfo {
    /// IncludeLoc - The location of the #include that brought in this file.
    /// This is an invalid SLOC for the main file (top of the #include chain).
    unsigned IncludeLoc;  // Really a SourceLocation

    /// Data - This contains the ContentCache* and the bits indicating the
    /// characteristic of the file and whether it has #line info, all bitmangled
    /// together.
    uintptr_t Data;
  public:
    /// get - Return a FileInfo object.
    static FileInfo get(SourceLocation IL, const ContentCache *Con,
                        CharacteristicKind FileCharacter) {
      FileInfo X;
      X.IncludeLoc = IL.getRawEncoding();
      X.Data = (uintptr_t)Con;
      assert((X.Data & 7) == 0 &&"ContentCache pointer insufficiently aligned");
      assert((unsigned)FileCharacter < 4 && "invalid file character");
      X.Data |= (unsigned)FileCharacter;
      return X;
    }

    SourceLocation getIncludeLoc() const {
      return SourceLocation::getFromRawEncoding(IncludeLoc);
    }
    const ContentCache* getContentCache() const {
      return reinterpret_cast<const ContentCache*>(Data & ~7UL);
    }

    /// getCharacteristic - Return whether this is a system header or not.
    CharacteristicKind getFileCharacteristic() const {
      return