db/morkreader/nsMorkReader.h
author Andreas Gal <gal@mozilla.com>
Wed, 23 Jul 2008 02:57:56 -0700
changeset 17811 711092884c032410bd635b1d68ef9c778afa3777
parent 15605 f0a281f4e165df9cb0eabccfa2dc7e018d897b20
child 20261 eee86e5513ad381eaa16a55f037fa479c8d54187
permissions -rw-r--r--
Lazy fill the stackTracker as we lookup the nativeFrameOffset for values. Purge all entries related to the current frame when it is popped. This code could be further simplified if Tracker was a template.

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Mork Reader.
 *
 * The Initial Developer of the Original Code is
 * Google Inc.
 * Portions created by the Initial Developer are Copyright (C) 2006
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Brian Ryner <bryner@brianryner.com> (original author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef nsMorkReader_h_
#define nsMorkReader_h_

#include "nsDataHashtable.h"
#include "nsILineInputStream.h"
#include "nsTArray.h"
#include "nsAutoPtr.h"

// The nsMorkReader object allows a consumer to read in a mork-format
// file and enumerate the rows that it contains.  It does not provide
// any functionality for modifying mork tables.

// References:
//  http://www.mozilla.org/mailnews/arch/mork/primer.txt
//  http://www.mozilla.org/mailnews/arch/mork/grammar.txt
//  http://www.jwz.org/hacks/mork.pl

class NS_STACK_CLASS nsMorkReader
{
 public:
  // This string type has built-in storage for the hex string representation
  // of a 32-bit row id or atom map key, plus the terminating null.
  class IDString : public nsFixedCString
  {
  public:
    IDString() : fixed_string_type(mStorage, sizeof(mStorage), 0) {}
    IDString(const substring_type &str) :
      fixed_string_type(mStorage, sizeof(mStorage), 0)
    {
      Assign(str);
    }

  private:
    char_type mStorage[9];
  };

  // Hashtable key type that contains an IDString
  class IDKey : public PLDHashEntryHdr
  {
  public:
    typedef const nsCSubstring& KeyType;
    typedef const nsCSubstring* KeyTypePointer;

    IDKey(KeyTypePointer aStr) : mStr(*aStr) { }
    IDKey(const IDKey& toCopy) : mStr(toCopy.mStr) { }
    ~IDKey() { }

    KeyType GetKey() const { return mStr; }
    PRBool KeyEquals(const KeyTypePointer aKey) const
    {
      return mStr.Equals(*aKey);
    }

    static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
    static PLDHashNumber HashKey(const KeyTypePointer aKey)
    {
      return HashString(*aKey);
    }
    enum { ALLOW_MEMMOVE = PR_FALSE };

  private:
    const IDString mStr;
  };

  // A convenience typedef for an IDKey-to-string mapping.
  typedef nsDataHashtable<IDKey,nsCString> StringMap;

  // A convenience typdef for an IDKey-to-index mapping, used for the
  // column index hashtable.
  typedef nsDataHashtable<IDKey,PRInt32> IndexMap;

  // A MorkColumn represents the data associated with a single table column.
  struct MorkColumn
  {
    MorkColumn(const nsCSubstring &i, const nsCSubstring &n)
      : id(i), name(n) {}

    IDString id;
    nsCString name;
  };

  // Enumerator callback type for processing table rows.
  // A row contains cells.  Each cell specifies a column id, and the value
  // for the column for that row.
  // rowID is the table-unique row id
  // values contains the cell values, in an order which corresponds to
  //   the columns returned by GetColumns().
  //   You should call NormalizeValue() on any cell value that you plan to use.
  // userData is the opaque pointer passed to EnumerateRows()
  // The callback can return PL_DHASH_NEXT to continue enumerating,
  // or PL_DHASH_STOP to stop.
  typedef PLDHashOperator
  (*PR_CALLBACK RowEnumerator)(const nsCSubstring &rowID, 
                               const nsTArray<nsCString> *values,
                               void *userData);

  // Initialize the importer object's data structures
  nsresult Init();

  // Read in the given mork file
  // Note: currently, only single-table mork files are supported
  nsresult Read(nsIFile *aFile);

  // Returns the list of columns in the current table.
  const nsTArray<MorkColumn>& GetColumns() const { return mColumns; }

  // Enumerate the rows in the current table.
  void EnumerateRows(RowEnumerator aCallback, void *aUserData) const;

  // Get the "meta row" for the table.  Each table has at most one meta row,
  // which records information about the table.  Like normal rows, the
  // meta row contains columns in the same order as returned by GetColumns().
  // Returns null if there is no meta row for this table.
  const nsTArray<nsCString>* GetMetaRow() const { return mMetaRow; }

  // Normalizes the cell value (resolves references to the value map).
  // aValue is modified in-place.
  void NormalizeValue(nsCString &aValue) const;

  nsMorkReader() {}
  ~nsMorkReader();

private:
  // Parses a line of the file which contains key/value pairs (either
  // the column map or the value map).  Additional lines are read from
  // mStream if the line ends mid-entry.  The pairs are added to aMap.
  nsresult ParseMap(const nsCSubstring &aLine, StringMap *aMap);

  // Parses a line of the file which contains a table or row definition.
  // Additional lines are read from mStream of the line ends mid-row.
  // An entry is added to mTable using the row ID as the key, which contains
  // a column array for the row.  The supplied column hash table maps from
  // column id to an index in mColumns.
  nsresult ParseTable(const nsCSubstring &aLine, const IndexMap &aColumnMap);

  // Reads a single logical line from mStream into aLine.
  // Any continuation lines are consumed and appended to the line.
  nsresult ReadLine(nsCString &aLine);

  // Create a new nsCString array and fill it with the supplied number
  // of void strings.  Returns null on out-of-memory.
  static nsTArray<nsCString>* NewVoidStringArray(PRInt32 aSize);

  nsTArray<MorkColumn> mColumns;
  StringMap mValueMap;
  nsAutoPtr< nsTArray<nsCString> > mMetaRow;
  nsDataHashtable< IDKey,nsTArray<nsCString>* > mTable;
  nsCOMPtr<nsILineInputStream> mStream;
  nsCString mEmptyString; // note: not EmptyCString() since that's not sharable
};

#endif // nsMorkReader_h_