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): 
 * This Original Code has been modified by IBM Corporation.
 * Modifications made by IBM described herein are
 * Copyright (c) International Business Machines
 * Corporation, 2000
 *
 * Modifications to Mozilla code or documentation
 * identified per MPL Section 3.3
 *
 * Date         Modified by     Description of modification
 * 04/20/2000   IBM Corp.       Added PR_CALLBACK for Optlink use in OS2
 */

#ifndef nsHashtable_h__
#define nsHashtable_h__

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

class nsHashtable;
class nsStringKey;

class NS_COM nsHashKey {
protected:
  nsHashKey(void);

public:
  virtual ~nsHashKey(void);
  virtual PRUint32 HashCode(void) const = 0;
  virtual PRBool Equals(const nsHashKey *aKey) const = 0;
  virtual nsHashKey *Clone() const = 0;

#ifdef DEBUG
public:
  // used for verification that we're casting to the correct key type
  enum nsHashKeyType {
    UnknownKey,
    SupportsKey,
    VoidKey,
    IDKey,
    CStringKey,
    StringKey,
    OpaqueKey
  };
  nsHashKeyType GetKeyType() const { return mKeyType; }
protected:
  nsHashKeyType mKeyType;
#endif
};

// Enumerator callback function. Use

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

class NS_COM nsHashtable {
protected:
  // members  
  PRLock*               mLock;
  PLHashTable           mHashtable;
  PRBool                mEnumerating;

public:
  nsHashtable(PRUint32 aSize = 16, PRBool threadSafe = PR_FALSE);
  virtual ~nsHashtable();

  PRInt32 Count(void) { return mHashtable.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* (*PR_CALLBACK 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 = 16, PRBool threadSafe = PR_FALSE);
  ~nsObjectHashtable();

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

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

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

class nsISupports;

class NS_COM nsSupportsHashtable
 : private nsHashtable
{
public:
  typedef PRBool (* PR_CALLBACK EnumFunc) (nsHashKey *aKey, void *aData, void* closure);

  nsSupportsHashtable(PRUint32 aSize = 16, PRBool threadSafe = PR_FALSE)
    : nsHashtable(aSize, threadSafe) {}
  ~nsSupportsHashtable();

  PRInt32 Count (void)
  {
    return nsHashtable::Count();
  }
  PRBool Exists (nsHashKey *aKey)
  {
    return nsHashtable::Exists (aKey);
  }
  PRBool Put (nsHashKey *aKey,
              nsISupports *aData,
              nsISupports **value = nsnull);
  nsISupports* Get (nsHashKey *aKey);
  PRBool Remove (nsHashKey *aKey, nsISupports **value = nsnull);
  nsHashtable *Clone();
  void Enumerate (EnumFunc aEnumFunc, void* closure = NULL)
  {
    nsHashtable::Enumerate (aEnumFunc, closure);
  }
  void Reset();

 private:
  static PRBool PR_CALLBACK ReleaseElement (nsHashKey *, void *, void *);
  static PRIntn PR_CALLBACK EnumerateCopy (PLHashEntry *, PRIntn, void *);
};

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

#include "nsISupports.h"

class nsISupportsKey : public nsHashKey {
protected:
  nsISupports* mKey;
  
public:
  nsISupportsKey(nsISupports* key) {
#ifdef DEBUG
    mKeyType = SupportsKey;
#endif
    mKey = key;
    NS_IF_ADDREF(mKey);
  }
  
  ~nsISupportsKey(void) {
    NS_IF_RELEASE(mKey);
  }
  
  PRUint32 HashCode(void) const {
    return (PRUint32)mKey;
  }

  PRBool Equals(const nsHashKey *aKey) const {
    NS_ASSERTION(aKey->GetKeyType() == SupportsKey, "mismatched key types");
    return (mKey == ((nsISupportsKey *) aKey)->mKey);
  }

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

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

class nsVoidKey : public nsHashKey {
protected:
  void* mKey;
  
public:
  nsVoidKey(void* key) {
#ifdef DEBUG
    mKeyType = VoidKey;
#endif
    mKey = key;
  }
  
  PRUint32 HashCode(void) const {
    return (PRUint32)mKey;
  }

  PRBool Equals(const nsHashKey *aKey) const {
    NS_ASSERTION(aKey->GetKeyType() == VoidKey, "mismatched key types");
    return (mKey == ((const nsVoidKey *) aKey)->mKey);
  }

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

  void* GetValue() { return 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) {
#ifdef DEBUG
    mKeyType = IDKey;
#endif
    mID = aID;
  }
  
  PRUint32 HashCode(void) const {
    return mID.m0;
  }

  PRBool Equals(const nsHashKey *aKey) const {
    NS_ASSERTION(aKey->GetKeyType() == IDKey, "mismatched key types");
    return (mID.Equals(((const nsIDKey *) aKey)->mID));
  }

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

////////////////////////////////////////////////////////////////////////////////

#include "nsString.h"

// for null-terminated c-strings
class NS_COM nsCStringKey : public nsHashKey {
public:

  enum Ownership {
    NEVER_OWN,  // 'str' is very long lived, even clones don't need to copy it.
    OWN_CLONE,  // 'str' is as long lived as this key. But clones make a copy.
    OWN         // 'str' to be free'd in key dtor. Clones make their own copy.
  };

  nsCStringKey(const char* str, PRInt32 strLen = -1, Ownership own = OWN_CLONE);
  nsCStringKey(const nsCString& str);
  ~nsCStringKey(void);

  PRUint32 HashCode(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 char* GetString() const { return mStr; }
  PRUint32 GetStringLength() const { return mStrLen; }

protected:
  char*         mStr;
  PRUint32      mStrLen;
  Ownership     mOwnership;
};

// for null-terminated unicode strings
class NS_COM nsStringKey : public nsHashKey {
public:

  enum Ownership {
    NEVER_OWN,  // 'str' is very long lived, even clones don't need to copy it.
    OWN_CLONE,  // 'str' is as long lived as this key. But clones make a copy.
    OWN         // 'str' to be free'd in key dtor. Clones make their own copy.
  };

  nsStringKey(const PRUnichar* str, PRInt32 strLen = -1, Ownership own = OWN_CLONE);
  nsStringKey(const nsAReadableString& str);
  ~nsStringKey(void);

  PRUint32 HashCode(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 PRUnichar* GetString() const { return mStr; }
  PRUint32 GetStringLength() const { return mStrLen; }

protected:
  PRUnichar*    mStr;
  PRUint32      mStrLen;
  Ownership     mOwnership;
};

// for opaque buffers of data which may contain nulls
class NS_COM nsOpaqueKey : public nsHashKey {
public:

  enum Ownership {
    NEVER_OWN,  // 'buf' is very long lived, even clones don't need to copy it.
    OWN_CLONE,  // 'buf' is as long lived as this key. But clones make a copy.
    OWN         // 'buf' to be free'd in key dtor. Clones make their own copy.
  };

  nsOpaqueKey(const char* buf, PRUint32 bufLen, Ownership own = OWN_CLONE);
  ~nsOpaqueKey(void);

  PRUint32 HashCode(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 char* GetBuffer() const { return mBuf; }
  PRUint32 GetBufferLength() const { return mBufLen; }

protected:
  char*         mBuf;
  PRUint32      mBufLen;
  Ownership     mOwnership;
};

////////////////////////////////////////////////////////////////////////////////

#endif