gecko-dev/xpcom/ds/nsHashtable.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
 * The contents of this file are subject to the Netscape 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/NPL/
 *
 * 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 mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */

#ifndef nsHashtable_h__
#define nsHashtable_h__

#include "plhash.h"
#include "prlock.h"
#include "nsCom.h"

class NS_COM nsHashKey {
protected:
  nsHashKey(void);
public:
  virtual ~nsHashKey(void);
  virtual PRUint32 HashValue(void) const = 0;
  virtual PRBool Equals(const nsHashKey *aKey) const = 0;
  virtual nsHashKey *Clone(void) const = 0;
};

// Enumerator callback function. Use

typedef PRBool (*nsHashtableEnumFunc)(nsHashKey *aKey, void *aData, void* closure);

class NS_COM nsHashtable {
protected:
  // members  
  PLHashTable *hashtable;
  PRLock *mLock;

public:
  nsHashtable(PRUint32 aSize = 256, PRBool threadSafe = PR_FALSE);
  ~nsHashtable();

  PRInt32 Count(void) { return hashtable->nentries; }
  PRBool Exists(nsHashKey *aKey);
  void *Put(nsHashKey *aKey, void *aData);
  void *Get(nsHashKey *aKey);
  void *Remove(nsHashKey *aKey);
  nsHashtable *Clone();
  void Enumerate(nsHashtableEnumFunc aEnumFunc, void* closure = NULL);
  void Reset();
  void Reset(nsHashtableEnumFunc destroyFunc, void* closure = NULL);
};

////////////////////////////////////////////////////////////////////////////////
// nsObjectHashtable: an nsHashtable where the elements are C++ objects to be
// deleted

typedef void* (*nsHashtableCloneElementFunc)(nsHashKey *aKey, void *aData, void* closure);

class NS_COM nsObjectHashtable : public nsHashtable {
public:
  nsObjectHashtable(nsHashtableCloneElementFunc cloneElementFun,
                    void* cloneElementClosure,
                    nsHashtableEnumFunc destroyElementFun,
                    void* destroyElementClosure,
                    PRUint32 aSize = 256, PRBool threadSafe = PR_FALSE);
  ~nsObjectHashtable();

  nsHashtable *Clone();
  void Reset();
  PRBool RemoveAndDelete(nsHashKey *aKey);

protected:
  static PR_CALLBACK PRIntn CopyElement(PLHashEntry *he, PRIntn i, void *arg);
  
  nsHashtableCloneElementFunc   mCloneElementFun;
  void*                         mCloneElementClosure;
  nsHashtableEnumFunc           mDestroyElementFun;
  void*                         mDestroyElementClosure;
};

////////////////////////////////////////////////////////////////////////////////
// nsSupportsHashtable: an nsHashtable where the elements are nsISupports*

class NS_COM nsSupportsHashtable : public nsHashtable {
public:
  nsSupportsHashtable(PRUint32 aSize = 256, PRBool threadSafe = PR_FALSE)
    : nsHashtable(aSize, threadSafe) {}
  ~nsSupportsHashtable();

  void *Put(nsHashKey *aKey, void *aData);
  void *Get(nsHashKey *aKey);
  void *Remove(nsHashKey *aKey);
  nsHashtable *Clone();
  void Reset();
};

////////////////////////////////////////////////////////////////////////////////
// nsISupportsKey: Where keys are nsISupports objects that get refcounted.

#include "nsISupports.h"

class nsISupportsKey : public nsHashKey {
protected:
  nsISupports* mKey;
  
public:
  nsISupportsKey(nsISupports* key) {
    mKey = key;
    NS_IF_ADDREF(mKey);
  }
  
  ~nsISupportsKey(void) {
    NS_IF_RELEASE(mKey);
  }
  
  PRUint32 HashValue(void) const {
    return (PRUint32)mKey;
  }

  PRBool Equals(const nsHashKey *aKey) const {
    return (mKey == ((nsISupportsKey *) aKey)->mKey);
  }

  nsHashKey *Clone(void) const {
    return new nsISupportsKey(mKey);
  }
};

////////////////////////////////////////////////////////////////////////////////
// nsVoidKey: Where keys are void* objects that don't get refcounted.

class nsVoidKey : public nsHashKey {
protected:
  const void* mKey;
  
public:
  nsVoidKey(const void* key) {
    mKey = key;
  }
  
  PRUint32 HashValue(void) const {
    return (PRUint32)mKey;
  }

  PRBool Equals(const nsHashKey *aKey) const {
    return (mKey == ((const nsVoidKey *) aKey)->mKey);
  }

  nsHashKey *Clone(void) const {
    return new nsVoidKey(mKey);
  }
};

////////////////////////////////////////////////////////////////////////////////
// nsIDKey: Where keys are nsIDs (e.g. nsIID, nsCID).

#include "nsID.h"

class nsIDKey : public nsHashKey {
protected:
  nsID mID;
  
public:
  nsIDKey(const nsID &aID) {
    mID = aID;
  }
  
  PRUint32 HashValue(void) const {
    return mID.m0;
  }

  PRBool Equals(const nsHashKey *aKey) const {
    return (mID.Equals(((const nsIDKey *) aKey)->mID));
  }

  nsHashKey *Clone(void) const {
    return new nsIDKey(mID);
  }
};

////////////////////////////////////////////////////////////////////////////////
// nsStringKey: Where keys are PRUnichar* or char*
// Some uses: hashing ProgIDs, filenames, URIs

#include "nsString.h"

class NS_COM nsStringKey : public nsHashKey {
protected:
  nsAutoString mStr;

public:
  nsStringKey(const char* str);
  nsStringKey(const PRUnichar* str);
  nsStringKey(const nsStr& str);

  ~nsStringKey(void);

  PRUint32 HashValue(void) const;

  PRBool Equals(const nsHashKey* aKey) const;

  nsHashKey* Clone() const;

  // For when the owner of the hashtable wants to peek at the actual
  // string in the key. No copy is made, so be careful.
  const nsString& GetString() const;
};

////////////////////////////////////////////////////////////////////////////////
// nsOpaqueKey: Where keys are opaque byte-array blobs

#include "nsString.h"

class NS_COM nsOpaqueKey : public nsHashKey {
protected:
  const char* mOpaqueKey;         // Byte array of opaque data
  PRUint32    mKeyLength;         // Length, in bytes, of mOpaqueKey

public:
  // Note opaque keys are not copied by this constructor.  If you want a private
  // copy in each hash key, you must create one and pass it in to this function.
  nsOpaqueKey(const char* aOpaqueKey, PRUint32 aKeyLength);

  ~nsOpaqueKey(void);

  PRUint32 HashValue(void) const;
  PRBool Equals(const nsHashKey* aKey) const;
  nsHashKey* Clone() const;

  // For when the owner of the hashtable wants to peek at the actual
  // opaque array in the key. No copy is made, so be careful.
  const char* GetKey() const;
  PRUint32 GetKeyLength() const;
};

#endif