1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/glue/nsArrayEnumerator.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,207 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "mozilla/Attributes.h"
1.10 +
1.11 +#include "nsArrayEnumerator.h"
1.12 +
1.13 +#include "nsIArray.h"
1.14 +#include "nsISimpleEnumerator.h"
1.15 +
1.16 +#include "nsCOMArray.h"
1.17 +#include "nsCOMPtr.h"
1.18 +
1.19 +class nsSimpleArrayEnumerator MOZ_FINAL : public nsISimpleEnumerator
1.20 +{
1.21 +public:
1.22 + // nsISupports interface
1.23 + NS_DECL_ISUPPORTS
1.24 +
1.25 + // nsISimpleEnumerator interface
1.26 + NS_DECL_NSISIMPLEENUMERATOR
1.27 +
1.28 + // nsSimpleArrayEnumerator methods
1.29 + nsSimpleArrayEnumerator(nsIArray* aValueArray) :
1.30 + mValueArray(aValueArray), mIndex(0) {
1.31 + }
1.32 +
1.33 +private:
1.34 + ~nsSimpleArrayEnumerator() {}
1.35 +
1.36 +protected:
1.37 + nsCOMPtr<nsIArray> mValueArray;
1.38 + uint32_t mIndex;
1.39 +};
1.40 +
1.41 +NS_IMPL_ISUPPORTS(nsSimpleArrayEnumerator, nsISimpleEnumerator)
1.42 +
1.43 +NS_IMETHODIMP
1.44 +nsSimpleArrayEnumerator::HasMoreElements(bool* aResult)
1.45 +{
1.46 + NS_PRECONDITION(aResult != 0, "null ptr");
1.47 + if (! aResult)
1.48 + return NS_ERROR_NULL_POINTER;
1.49 +
1.50 + if (!mValueArray) {
1.51 + *aResult = false;
1.52 + return NS_OK;
1.53 + }
1.54 +
1.55 + uint32_t cnt;
1.56 + nsresult rv = mValueArray->GetLength(&cnt);
1.57 + if (NS_FAILED(rv)) return rv;
1.58 + *aResult = (mIndex < cnt);
1.59 + return NS_OK;
1.60 +}
1.61 +
1.62 +NS_IMETHODIMP
1.63 +nsSimpleArrayEnumerator::GetNext(nsISupports** aResult)
1.64 +{
1.65 + NS_PRECONDITION(aResult != 0, "null ptr");
1.66 + if (! aResult)
1.67 + return NS_ERROR_NULL_POINTER;
1.68 +
1.69 + if (!mValueArray) {
1.70 + *aResult = nullptr;
1.71 + return NS_OK;
1.72 + }
1.73 +
1.74 + uint32_t cnt;
1.75 + nsresult rv = mValueArray->GetLength(&cnt);
1.76 + if (NS_FAILED(rv)) return rv;
1.77 + if (mIndex >= cnt)
1.78 + return NS_ERROR_UNEXPECTED;
1.79 +
1.80 + return mValueArray->QueryElementAt(mIndex++, NS_GET_IID(nsISupports), (void**)aResult);
1.81 +}
1.82 +
1.83 +nsresult
1.84 +NS_NewArrayEnumerator(nsISimpleEnumerator* *result,
1.85 + nsIArray* array)
1.86 +{
1.87 + nsSimpleArrayEnumerator* enumer = new nsSimpleArrayEnumerator(array);
1.88 + if (enumer == nullptr)
1.89 + return NS_ERROR_OUT_OF_MEMORY;
1.90 +
1.91 + NS_ADDREF(*result = enumer);
1.92 + return NS_OK;
1.93 +}
1.94 +
1.95 +////////////////////////////////////////////////////////////////////////////////
1.96 +
1.97 +// enumerator implementation for nsCOMArray
1.98 +// creates a snapshot of the array in question
1.99 +// you MUST use NS_NewArrayEnumerator to create this, so that
1.100 +// allocation is done correctly
1.101 +class nsCOMArrayEnumerator MOZ_FINAL : public nsISimpleEnumerator
1.102 +{
1.103 +public:
1.104 + // nsISupports interface
1.105 + NS_DECL_ISUPPORTS
1.106 +
1.107 + // nsISimpleEnumerator interface
1.108 + NS_DECL_NSISIMPLEENUMERATOR
1.109 +
1.110 + // nsSimpleArrayEnumerator methods
1.111 + nsCOMArrayEnumerator() : mIndex(0) {
1.112 + }
1.113 +
1.114 + // specialized operator to make sure we make room for mValues
1.115 + void* operator new (size_t size, const nsCOMArray_base& aArray) CPP_THROW_NEW;
1.116 + void operator delete(void* ptr) {
1.117 + ::operator delete(ptr);
1.118 + }
1.119 +
1.120 +private:
1.121 + ~nsCOMArrayEnumerator(void);
1.122 +
1.123 +protected:
1.124 + uint32_t mIndex; // current position
1.125 + uint32_t mArraySize; // size of the array
1.126 +
1.127 + // this is actually bigger
1.128 + nsISupports* mValueArray[1];
1.129 +};
1.130 +
1.131 +NS_IMPL_ISUPPORTS(nsCOMArrayEnumerator, nsISimpleEnumerator)
1.132 +
1.133 +nsCOMArrayEnumerator::~nsCOMArrayEnumerator()
1.134 +{
1.135 + // only release the entries that we haven't visited yet
1.136 + for (; mIndex < mArraySize; ++mIndex) {
1.137 + NS_IF_RELEASE(mValueArray[mIndex]);
1.138 + }
1.139 +}
1.140 +
1.141 +NS_IMETHODIMP
1.142 +nsCOMArrayEnumerator::HasMoreElements(bool* aResult)
1.143 +{
1.144 + NS_PRECONDITION(aResult != 0, "null ptr");
1.145 + if (! aResult)
1.146 + return NS_ERROR_NULL_POINTER;
1.147 +
1.148 + *aResult = (mIndex < mArraySize);
1.149 + return NS_OK;
1.150 +}
1.151 +
1.152 +NS_IMETHODIMP
1.153 +nsCOMArrayEnumerator::GetNext(nsISupports** aResult)
1.154 +{
1.155 + NS_PRECONDITION(aResult != 0, "null ptr");
1.156 + if (! aResult)
1.157 + return NS_ERROR_NULL_POINTER;
1.158 +
1.159 + if (mIndex >= mArraySize)
1.160 + return NS_ERROR_UNEXPECTED;
1.161 +
1.162 + // pass the ownership of the reference to the caller. Since
1.163 + // we AddRef'ed during creation of |this|, there is no need
1.164 + // to AddRef here
1.165 + *aResult = mValueArray[mIndex++];
1.166 +
1.167 + // this really isn't necessary. just pretend this happens, since
1.168 + // we'll never visit this value again!
1.169 + // mValueArray[(mIndex-1)] = nullptr;
1.170 +
1.171 + return NS_OK;
1.172 +}
1.173 +
1.174 +void*
1.175 +nsCOMArrayEnumerator::operator new (size_t size, const nsCOMArray_base& aArray)
1.176 + CPP_THROW_NEW
1.177 +{
1.178 + // create enough space such that mValueArray points to a large
1.179 + // enough value. Note that the initial value of size gives us
1.180 + // space for mValueArray[0], so we must subtract
1.181 + size += (aArray.Count() - 1) * sizeof(aArray[0]);
1.182 +
1.183 + // do the actual allocation
1.184 + nsCOMArrayEnumerator * result =
1.185 + static_cast<nsCOMArrayEnumerator*>(::operator new(size));
1.186 +
1.187 + // now need to copy over the values, and addref each one
1.188 + // now this might seem like a lot of work, but we're actually just
1.189 + // doing all our AddRef's ahead of time since GetNext() doesn't
1.190 + // need to AddRef() on the way out
1.191 + uint32_t i;
1.192 + uint32_t max = result->mArraySize = aArray.Count();
1.193 + for (i = 0; i<max; i++) {
1.194 + result->mValueArray[i] = aArray[i];
1.195 + NS_IF_ADDREF(result->mValueArray[i]);
1.196 + }
1.197 +
1.198 + return result;
1.199 +}
1.200 +
1.201 +nsresult
1.202 +NS_NewArrayEnumerator(nsISimpleEnumerator* *aResult,
1.203 + const nsCOMArray_base& aArray)
1.204 +{
1.205 + nsCOMArrayEnumerator *enumerator = new (aArray) nsCOMArrayEnumerator();
1.206 + if (!enumerator) return NS_ERROR_OUT_OF_MEMORY;
1.207 +
1.208 + NS_ADDREF(*aResult = enumerator);
1.209 + return NS_OK;
1.210 +}
