michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: 
michael@0: #include "nsArrayEnumerator.h"
michael@0: 
michael@0: #include "nsIArray.h"
michael@0: #include "nsISimpleEnumerator.h"
michael@0: 
michael@0: #include "nsCOMArray.h"
michael@0: #include "nsCOMPtr.h"
michael@0: 
michael@0: class nsSimpleArrayEnumerator MOZ_FINAL : public nsISimpleEnumerator
michael@0: {
michael@0: public:
michael@0:     // nsISupports interface
michael@0:     NS_DECL_ISUPPORTS
michael@0: 
michael@0:     // nsISimpleEnumerator interface
michael@0:     NS_DECL_NSISIMPLEENUMERATOR
michael@0: 
michael@0:     // nsSimpleArrayEnumerator methods
michael@0:     nsSimpleArrayEnumerator(nsIArray* aValueArray) :
michael@0:         mValueArray(aValueArray), mIndex(0) {
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     ~nsSimpleArrayEnumerator() {}
michael@0: 
michael@0: protected:
michael@0:     nsCOMPtr<nsIArray> mValueArray;
michael@0:     uint32_t mIndex;
michael@0: };
michael@0: 
michael@0: NS_IMPL_ISUPPORTS(nsSimpleArrayEnumerator, nsISimpleEnumerator)
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsSimpleArrayEnumerator::HasMoreElements(bool* aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if (!mValueArray) {
michael@0:         *aResult = false;
michael@0:         return NS_OK;
michael@0:     }
michael@0: 
michael@0:     uint32_t cnt;
michael@0:     nsresult rv = mValueArray->GetLength(&cnt);
michael@0:     if (NS_FAILED(rv)) return rv;
michael@0:     *aResult = (mIndex < cnt);
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsSimpleArrayEnumerator::GetNext(nsISupports** aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if (!mValueArray) {
michael@0:         *aResult = nullptr;
michael@0:         return NS_OK;
michael@0:     }
michael@0: 
michael@0:     uint32_t cnt;
michael@0:     nsresult rv = mValueArray->GetLength(&cnt);
michael@0:     if (NS_FAILED(rv)) return rv;
michael@0:     if (mIndex >= cnt)
michael@0:         return NS_ERROR_UNEXPECTED;
michael@0: 
michael@0:     return mValueArray->QueryElementAt(mIndex++, NS_GET_IID(nsISupports), (void**)aResult);
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: NS_NewArrayEnumerator(nsISimpleEnumerator* *result,
michael@0:                       nsIArray* array)
michael@0: {
michael@0:     nsSimpleArrayEnumerator* enumer = new nsSimpleArrayEnumerator(array);
michael@0:     if (enumer == nullptr)
michael@0:         return NS_ERROR_OUT_OF_MEMORY;
michael@0: 
michael@0:     NS_ADDREF(*result = enumer);
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: // enumerator implementation for nsCOMArray
michael@0: // creates a snapshot of the array in question
michael@0: // you MUST use NS_NewArrayEnumerator to create this, so that
michael@0: // allocation is done correctly
michael@0: class nsCOMArrayEnumerator MOZ_FINAL : public nsISimpleEnumerator
michael@0: {
michael@0: public:
michael@0:     // nsISupports interface
michael@0:     NS_DECL_ISUPPORTS
michael@0: 
michael@0:     // nsISimpleEnumerator interface
michael@0:     NS_DECL_NSISIMPLEENUMERATOR
michael@0: 
michael@0:     // nsSimpleArrayEnumerator methods
michael@0:     nsCOMArrayEnumerator() : mIndex(0) {
michael@0:     }
michael@0: 
michael@0:     // specialized operator to make sure we make room for mValues
michael@0:     void* operator new (size_t size, const nsCOMArray_base& aArray) CPP_THROW_NEW;
michael@0:     void operator delete(void* ptr) {
michael@0:         ::operator delete(ptr);
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     ~nsCOMArrayEnumerator(void);
michael@0: 
michael@0: protected:
michael@0:     uint32_t mIndex;            // current position
michael@0:     uint32_t mArraySize;        // size of the array
michael@0:     
michael@0:     // this is actually bigger
michael@0:     nsISupports* mValueArray[1];
michael@0: };
michael@0: 
michael@0: NS_IMPL_ISUPPORTS(nsCOMArrayEnumerator, nsISimpleEnumerator)
michael@0: 
michael@0: nsCOMArrayEnumerator::~nsCOMArrayEnumerator()
michael@0: {
michael@0:     // only release the entries that we haven't visited yet
michael@0:     for (; mIndex < mArraySize; ++mIndex) {
michael@0:         NS_IF_RELEASE(mValueArray[mIndex]);
michael@0:     }
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsCOMArrayEnumerator::HasMoreElements(bool* aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     *aResult = (mIndex < mArraySize);
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsCOMArrayEnumerator::GetNext(nsISupports** aResult)
michael@0: {
michael@0:     NS_PRECONDITION(aResult != 0, "null ptr");
michael@0:     if (! aResult)
michael@0:         return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if (mIndex >= mArraySize)
michael@0:         return NS_ERROR_UNEXPECTED;
michael@0: 
michael@0:     // pass the ownership of the reference to the caller. Since
michael@0:     // we AddRef'ed during creation of |this|, there is no need
michael@0:     // to AddRef here
michael@0:     *aResult = mValueArray[mIndex++];
michael@0: 
michael@0:     // this really isn't necessary. just pretend this happens, since
michael@0:     // we'll never visit this value again!
michael@0:     // mValueArray[(mIndex-1)] = nullptr;
michael@0:     
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: void*
michael@0: nsCOMArrayEnumerator::operator new (size_t size, const nsCOMArray_base& aArray)
michael@0:     CPP_THROW_NEW
michael@0: {
michael@0:     // create enough space such that mValueArray points to a large
michael@0:     // enough value. Note that the initial value of size gives us
michael@0:     // space for mValueArray[0], so we must subtract
michael@0:     size += (aArray.Count() - 1) * sizeof(aArray[0]);
michael@0: 
michael@0:     // do the actual allocation
michael@0:     nsCOMArrayEnumerator * result =
michael@0:         static_cast<nsCOMArrayEnumerator*>(::operator new(size));
michael@0: 
michael@0:     // now need to copy over the values, and addref each one
michael@0:     // now this might seem like a lot of work, but we're actually just
michael@0:     // doing all our AddRef's ahead of time since GetNext() doesn't
michael@0:     // need to AddRef() on the way out
michael@0:     uint32_t i;
michael@0:     uint32_t max = result->mArraySize = aArray.Count();
michael@0:     for (i = 0; i<max; i++) {
michael@0:         result->mValueArray[i] = aArray[i];
michael@0:         NS_IF_ADDREF(result->mValueArray[i]);
michael@0:     }
michael@0: 
michael@0:     return result;
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: NS_NewArrayEnumerator(nsISimpleEnumerator* *aResult,
michael@0:                       const nsCOMArray_base& aArray)
michael@0: {
michael@0:     nsCOMArrayEnumerator *enumerator = new (aArray) nsCOMArrayEnumerator();
michael@0:     if (!enumerator) return NS_ERROR_OUT_OF_MEMORY;
michael@0: 
michael@0:     NS_ADDREF(*aResult = enumerator);
michael@0:     return NS_OK;
michael@0: }