gecko-dev/db/morkreader/nsMorkReader.h

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/* -*- 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
(* 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_