virtualFileSimple.cxx

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file virtualFileSimple.cxx
 * @author drose
 * @date 2002-08-03
 */

#include "virtualFileSimple.h"
#include "virtualFileMount.h"
#include "virtualFileList.h"
#include "dcast.h"

using std::iostream;
using std::istream;
using std::ostream;
using std::string;

TypeHandle VirtualFileSimple::_type_handle;


/**
 * Returns the VirtualFileSystem this file is associated with.
 */
VirtualFileSystem *VirtualFileSimple::
get_file_system() const {
  return _mount->get_file_system();
}

/**
 * Returns the full pathname to this file within the virtual file system.
 */
Filename VirtualFileSimple::
get_filename() const {
  string mount_point = _mount->get_mount_point();
  if (_local_filename.empty()) {
    if (mount_point.empty()) {
      return "/";
    } else {
      return string("/") + mount_point;
    }

  } else {
    if (mount_point.empty()) {
      return string("/") + _local_filename.get_fullpath();
    } else {
      return string("/") + mount_point + string("/") + _local_filename.get_fullpath();
    }
  }
}

/**
 * Returns true if this file exists, false otherwise.
 */
bool VirtualFileSimple::
has_file() const {
  return _mount->has_file(_local_filename);
}

/**
 * Returns true if this file represents a directory (and scan_directory() may
 * be called), false otherwise.
 */
bool VirtualFileSimple::
is_directory() const {
  return _mount->is_directory(_local_filename);
}

/**
 * Returns true if this file represents a regular file (and read_file() may be
 * called), false otherwise.
 */
bool VirtualFileSimple::
is_regular_file() const {
  return _mount->is_regular_file(_local_filename);
}

/**
 * Returns true if this file represents a writable regular file (and
 * write_file() may be called), false otherwise.
 */
bool VirtualFileSimple::
is_writable() const {
  return _mount->is_writable(_local_filename);
}

/**
 * Attempts to delete this file or directory.  This can remove a single file
 * or an empty directory.  It will not remove a nonempty directory.  Returns
 * true on success, false on failure.
 */
bool VirtualFileSimple::
delete_file() {
  return _mount->delete_file(_local_filename);
}

/**
 * Attempts to move or rename this file or directory.  If the original file is
 * an ordinary file, it will quietly replace any already-existing file in the
 * new filename (but not a directory).  If the original file is a directory,
 * the new filename must not already exist.
 *
 * If the file is a directory, the new filename must be within the same mount
 * point.  If the file is an ordinary file, the new filename may be anywhere;
 * but if it is not within the same mount point then the rename operation is
 * automatically performed as a two-step copy-and-delete operation.
 */
bool VirtualFileSimple::
rename_file(VirtualFile *new_file) {
  if (new_file->is_of_type(VirtualFileSimple::get_class_type())) {
    VirtualFileSimple *new_file_simple = DCAST(VirtualFileSimple, new_file);
    if (new_file_simple->_mount == _mount) {
      // Same mount pount.
      if (_mount->rename_file(_local_filename, new_file_simple->_local_filename)) {
        return true;
      }
    }
  }

  // Different mount point, or the mount doesn't support renaming.  Do it by
  // hand.
  if (is_regular_file() && !new_file->is_directory()) {
    // copy-and-delete.
    new_file->delete_file();
    if (copy_file(new_file)) {
      delete_file();
      return true;
    }
  }

  return false;
}

/**
 * Attempts to copy the contents of this file to the indicated file.  Returns
 * true on success, false on failure.
 */
bool VirtualFileSimple::
copy_file(VirtualFile *new_file) {
  if (new_file->is_of_type(VirtualFileSimple::get_class_type())) {
    VirtualFileSimple *new_file_simple = DCAST(VirtualFileSimple, new_file);
    if (new_file_simple->_mount == _mount) {
      // Same mount pount.
      if (_mount->copy_file(_local_filename, new_file_simple->_local_filename)) {
        return true;
      }
    }
  }

  // Different mount point, or the mount doesn't support copying.  Do it by
  // hand.
  ostream *out = new_file->open_write_file(false, true);
  if (out == nullptr) {
    return false;
  }

  istream *in = open_read_file(false);
  if (in == nullptr) {
    new_file->close_write_file(out);
    new_file->delete_file();
    return false;
  }

  static const size_t buffer_size = 4096;
  char buffer[buffer_size];

  in->read(buffer, buffer_size);
  size_t count = in->gcount();
  while (count != 0) {
    out->write(buffer, count);
    if (out->fail()) {
      new_file->close_write_file(out);
      close_read_file(in);
      new_file->delete_file();
      return false;
    }
    in->read(buffer, buffer_size);
    count = in->gcount();
  }

  if (!in->eof()) {
    new_file->close_write_file(out);
    close_read_file(in);
    new_file->delete_file();
    return false;
  }

  new_file->close_write_file(out);
  close_read_file(in);
  return true;
}

/**
 * Opens the file for reading.  Returns a newly allocated istream on success
 * (which you should eventually delete when you are done reading). Returns
 * NULL on failure.
 *
 * If auto_unwrap is true, an explicitly-named .pz/.gz file is automatically
 * decompressed and the decompressed contents are returned.  This is different
 * than vfs-implicit-pz, which will automatically decompress a file if the
 * extension .pz is *not* given.
 */
istream *VirtualFileSimple::
open_read_file(bool auto_unwrap) const {

  // Will we be automatically unwrapping a .pz file?
  bool do_uncompress = (_implicit_pz_file ||
    (auto_unwrap && (_local_filename.get_extension() == "pz" ||
                     _local_filename.get_extension() == "gz")));

  Filename local_filename(_local_filename);
  if (do_uncompress) {
    // .pz files are always binary, of course.
    local_filename.set_binary();
  }

  return _mount->open_read_file(local_filename, do_uncompress);
}

/**
 * Closes a file opened by a previous call to open_read_file().  This really
 * just deletes the istream pointer, but it is recommended to use this
 * interface instead of deleting it explicitly, to help work around compiler
 * issues.
 */
void VirtualFileSimple::
close_read_file(istream *stream) const {
  _mount->close_read_file(stream);
}

/**
 * Opens the file for writing.  Returns a newly allocated ostream on success
 * (which you should eventually delete when you are done writing). Returns
 * NULL on failure.
 *
 * If auto_wrap is true, an explicitly-named .pz file is automatically
 * compressed while writing.  If truncate is true, the file is truncated to
 * zero length before writing.
 */
ostream *VirtualFileSimple::
open_write_file(bool auto_wrap, bool truncate) {
  // Will we be automatically wrapping a .pz file?
  bool do_compress = (_implicit_pz_file || (auto_wrap && _local_filename.get_extension() == "pz"));

  Filename local_filename(_local_filename);
  if (do_compress) {
    // .pz files are always binary, of course.
    local_filename.set_binary();
  }

  return _mount->open_write_file(local_filename, do_compress, truncate);
}

/**
 * Works like open_write_file(), but the file is opened in append mode.  Like
 * open_write_file, the returned pointer should eventually be passed to
 * close_write_file().
 */
ostream *VirtualFileSimple::
open_append_file() {
  return _mount->open_append_file(_local_filename);
}

/**
 * Closes a file opened by a previous call to open_write_file().  This really
 * just deletes the ostream pointer, but it is recommended to use this
 * interface instead of deleting it explicitly, to help work around compiler
 * issues.
 */
void VirtualFileSimple::
close_write_file(ostream *stream) {
  _mount->close_write_file(stream);
}

/**
 * Opens the file for writing.  Returns a newly allocated iostream on success
 * (which you should eventually delete when you are done writing). Returns
 * NULL on failure.
 */
iostream *VirtualFileSimple::
open_read_write_file(bool truncate) {
  return _mount->open_read_write_file(_local_filename, truncate);
}

/**
 * Works like open_read_write_file(), but the file is opened in append mode.
 * Like open_read_write_file, the returned pointer should eventually be passed
 * to close_read_write_file().
 */
iostream *VirtualFileSimple::
open_read_append_file() {
  return _mount->open_read_append_file(_local_filename);
}

/**
 * Closes a file opened by a previous call to open_read_write_file().  This
 * really just deletes the iostream pointer, but it is recommended to use this
 * interface instead of deleting it explicitly, to help work around compiler
 * issues.
 */
void VirtualFileSimple::
close_read_write_file(iostream *stream) {
  _mount->close_read_write_file(stream);
}

/**
 * Returns the current size on disk (or wherever it is) of the already-open
 * file.  Pass in the stream that was returned by open_read_file(); some
 * implementations may require this stream to determine the size.
 */
std::streamsize VirtualFileSimple::
get_file_size(istream *stream) const {
  return _mount->get_file_size(_local_filename, stream);
}

/**
 * Returns the current size on disk (or wherever it is) of the file before it
 * has been opened.
 */
std::streamsize VirtualFileSimple::
get_file_size() const {
  return _mount->get_file_size(_local_filename);
}

/**
 * Returns a time_t value that represents the time the file was last modified,
 * to within whatever precision the operating system records this information
 * (on a Windows95 system, for instance, this may only be accurate to within 2
 * seconds).
 *
 * If the timestamp cannot be determined, either because it is not supported
 * by the operating system or because there is some error (such as file not
 * found), returns 0.
 */
time_t VirtualFileSimple::
get_timestamp() const {
  return _mount->get_timestamp(_local_filename);
}

/**
 * Populates the SubfileInfo structure with the data representing where the
 * file actually resides on disk, if this is knowable.  Returns true if the
 * file might reside on disk, and the info is populated, or false if it does
 * not (or it is not known where the file resides), in which case the info is
 * meaningless.
 */
bool VirtualFileSimple::
get_system_info(SubfileInfo &info) {
  return _mount->get_system_info(_local_filename, info);
}

/**
 * See Filename::atomic_compare_and_exchange_contents().
 */
bool VirtualFileSimple::
atomic_compare_and_exchange_contents(string &orig_contents,
                                     const string &old_contents,
                                     const string &new_contents) {
  return _mount->atomic_compare_and_exchange_contents(_local_filename, orig_contents, old_contents, new_contents);
}

/**
 * See Filename::atomic_read_contents().
 */
bool VirtualFileSimple::
atomic_read_contents(string &contents) const {
  return _mount->atomic_read_contents(_local_filename, contents);
}

/**
 * Fills up the indicated pvector with the contents of the file, if it is a
 * regular file.  Returns true on success, false otherwise.
 */
bool VirtualFileSimple::
read_file(vector_uchar &result, bool auto_unwrap) const {

  // Will we be automatically unwrapping a .pz file?
  bool do_uncompress = (_implicit_pz_file ||
    (auto_unwrap && (_local_filename.get_extension() == "pz" ||
                     _local_filename.get_extension() == "gz")));

  Filename local_filename(_local_filename);
  if (do_uncompress) {
    // .pz files are always binary, of course.
    local_filename.set_binary();
  }

  return _mount->read_file(local_filename, do_uncompress, result);
}

/**
 * Writes the indicated data to the file, if it is writable.  Returns true on
 * success, false otherwise.
 */
bool VirtualFileSimple::
write_file(const unsigned char *data, size_t data_size, bool auto_wrap) {
  // Will we be automatically wrapping a .pz file?
  bool do_compress = (_implicit_pz_file || (auto_wrap && _local_filename.get_extension() == "pz"));

  Filename local_filename(_local_filename);
  if (do_compress) {
    // .pz files are always binary, of course.
    local_filename.set_binary();
  }

  return _mount->write_file(local_filename, do_compress, data, data_size);
}

/**
 * Fills file_list up with the list of files that are within this directory,
 * excluding those whose basenames are listed in mount_points.  Returns true
 * if successful, false if the file is not a directory or the directory cannot
 * be read.
 */
bool VirtualFileSimple::
scan_local_directory(VirtualFileList *file_list,
                     const ov_set<string> &mount_points) const {
  vector_string names;
  if (!_mount->scan_directory(names, _local_filename)) {
    return false;
  }

  // Now the scan above gave us a list of basenames.  Turn these back into
  // VirtualFile pointers.

  // Each of the files returned by the mount will be just a simple file within
  // the same mount tree, unless it is shadowed by a mount point listed in
  // mount_points.

  vector_string::const_iterator ni;
  for (ni = names.begin(); ni != names.end(); ++ni) {
    const string &basename = (*ni);
    if (mount_points.find(basename) == mount_points.end()) {
      Filename filename(_local_filename, basename);
      VirtualFileSimple *file = new VirtualFileSimple(_mount, filename, false, 0);
      file_list->add_file(file);
    }
  }

  return true;
}