lib/Bytecode/Archive/Archive.cpp

//===-- Archive.cpp - Generic LLVM archive functions ------------*- C++ -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Reid Spencer and is distributed under the 
// University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file contains the implementation of the Archive and ArchiveMember
// classes that is common to both reading and writing archives..
//
//===----------------------------------------------------------------------===//

#include "ArchiveInternals.h"
#include "llvm/ModuleProvider.h"

using namespace llvm;

// getMemberSize - compute the actual physical size of the file member as seen
// on disk. This isn't the size of member's payload. Use getSize() for that.
unsigned
ArchiveMember::getMemberSize() const {
  // Basically its the file size plus the header size
  unsigned result =  info.fileSize + sizeof(ArchiveMemberHeader);

  // If it has a long filename, include the name length
  if (hasLongFilename())
    result += path.get().length() + 1;

  // If its now odd lengthed, include the padding byte
  if (result % 2 != 0 ) 
    result++;

  return result;
}

// This default constructor is only use by the ilist when it creates its
// sentry node. We give it specific static values to make it stand out a bit.
ArchiveMember::ArchiveMember() 
  : next(0), prev(0), parent(0), path("<invalid>"), flags(0), data(0)
{
  info.user = 1000;
  info.group = 1000; 
  info.mode = 0777; 
  info.fileSize = 0; 
  info.modTime = sys::TimeValue::now();
}

// This is the constructor that the Archive class uses when it is building or
// reading an archive. It just defaults a few things and ensures the parent is
// set for the iplist. The Archive class fills in the ArchiveMember's data. 
// This is required because correctly setting the data may depend on other 
// things in the Archive.
ArchiveMember::ArchiveMember(Archive* PAR)
  : next(0), prev(0), parent(PAR), path(), flags(0), data(0)
{
}

// This method allows an ArchiveMember to be replaced with the data for a 
// different file, presumably as an update to the member. It also makes sure
// the flags are reset correctly.
void ArchiveMember::replaceWith(const sys::Path& newFile) {
  assert(newFile.exists() && "Can't replace with a non-existent file");
  data = 0;
  path = newFile;

  // Foreign symbol tables have an empty name
  if (path.get() == ARFILE_SYMTAB_NAME)
    flags |= ForeignSymbolTableFlag;
  else
    flags &= ~ForeignSymbolTableFlag;

  // LLVM symbol tables have a very specific name
  if (path.get() == ARFILE_LLVM_SYMTAB_NAME)
    flags |= LLVMSymbolTableFlag;
  else
    flags &= ~LLVMSymbolTableFlag;

  // String table name
  if (path.get() == ARFILE_STRTAB_NAME)
    flags |= StringTableFlag;
  else
    flags &= ~StringTableFlag;

  // If it has a slash then it has a path
  bool hasSlash = path.get().find('/') != std::string::npos;
  if (hasSlash)
    flags |= HasPathFlag;
  else
    flags &= ~HasPathFlag;

  // If it has a slash or its over 15 chars then its a long filename format
  if (hasSlash || path.get().length() > 15)
    flags |= HasLongFilenameFlag;
  else
    flags &= ~HasLongFilenameFlag;

  // Get the signature and status info
  std::string magic;
  const char* signature = (const char*) data;
  if (!signature) {
    path.getMagicNumber(magic,4);
    signature = magic.c_str();
    path.getStatusInfo(info);
  }

  // Determine what kind of file it is
  switch (sys::IdentifyFileType(signature,4)) {
    case sys::BytecodeFileType:
      flags |= BytecodeFlag;
      break;
    case sys::CompressedBytecodeFileType:
      flags |= CompressedBytecodeFlag;
      flags &= ~CompressedFlag;
      break;
    default:
      flags &= ~(BytecodeFlag|CompressedBytecodeFlag);
      break;
  }
}

// Archive constructor - this is the only constructor that gets used for the
// Archive class. Everything else (default,copy) is deprecated. This just 
// initializes and maps the file into memory, if requested.
Archive::Archive(const sys::Path& filename, bool map ) 
  : archPath(filename), members(), mapfile(0), base(0), symTab(), symTabSize(0)
{
  if (map) {
    mapfile = new sys::MappedFile(filename);
    base = (char*) mapfile->map();
  }
}

// Archive destructor - just clean up memory
Archive::~Archive() {
  // Shutdown the file mapping
  if (mapfile) {
    mapfile->unmap();
    delete mapfile;
  }
  // Delete any ModuleProviders and ArchiveMember's we've allocated as a result
  // of symbol table searches.
  for (ModuleMap::iterator I=modules.begin(), E=modules.end(); I != E; ++I ) {
    delete I->second.first;
    delete I->second.second;
  }
}

// vim: sw=2 ai