93 строки
3.2 KiB
C++
93 строки
3.2 KiB
C++
// Copyright (c) Microsoft Corporation. All rights reserved.
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#include "pal/PAL.hpp"
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#include "InformationProviderImpl.hpp"
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#include <vector>
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#ifdef _WIN32
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// Add SEH handling to callbacks to avoid crashes on Windows 10 Phone as a temporary
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// solution to cover unknown Windows 10 Phone scenarios, where app goes to background,
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// being shutdown or unloaded. And callback (power or network) fires at this time,
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// resulting in invalid pointer read from OnChanged. Worst case is instead of a crash
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// we would not refresh the actual network
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#include <exception>
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#include <excpt.h>
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#endif
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namespace PAL_NS_BEGIN {
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InformatonProviderImpl::InformatonProviderImpl() :m_registeredCount(0)
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{
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}
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InformatonProviderImpl::~InformatonProviderImpl()
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{
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}
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// IInformationProvider API
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int InformatonProviderImpl::RegisterInformationChangedCallback(IPropertyChangedCallback* pCallback)
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{
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std::lock_guard<std::mutex> lock(m_lock);
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// Use (index + 1) as the token.
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m_callbacks.push_back(pCallback);
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int token = (int)m_callbacks.size();
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m_registeredCount++;
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return token;
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}
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void InformatonProviderImpl::UnRegisterInformationChangedCallback(int callbackToken)
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{
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size_t index = (size_t)(callbackToken - 1);
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std::lock_guard<std::mutex> lock(m_lock);
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size_t count = m_callbacks.size();
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if (index > 0 && index < count)
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{
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// Don't ever delete the item from the vector.
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// Just set it to NULL.
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m_callbacks[index] = NULL;
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--m_registeredCount;
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}
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}
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void InformatonProviderImpl::OnChanged(std::string const& propertyName, std::string const& propertyValue)
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{
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try {
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// OnChange shouldn't block new callbacks to be registered.
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// However, those newly registered callbacks are not called by
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// this current notification.
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//
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// OnChange shouldn't block unregistration of callbacks. However,
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// those callbacks will be called by this current notification?
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// TODO: This means that after calling UnRegisterInformationChangedCallback
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// the client code is not sure if the IPropertyChangedCallback can
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// be deleted. The current design is that IPropertyChangedCallback is
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// not refcount'ed. Should we refcount it?
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if (m_registeredCount > 0)
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{
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std::vector<IPropertyChangedCallback*> local_callbacks;
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{
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std::lock_guard<std::mutex> lock(m_lock);
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local_callbacks.insert(local_callbacks.end(), m_callbacks.begin(), m_callbacks.end());
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}
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size_t count = local_callbacks.size();
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for (size_t index = 0; index < count; ++index)
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{
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IPropertyChangedCallback* cur_callback = local_callbacks[index];
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if (cur_callback != NULL)
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{
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cur_callback->OnChanged(propertyName, propertyValue);
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}
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}
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}
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}
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catch (...)
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{
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}
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}
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} PAL_NS_END
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