66 lines
1.8 KiB
C
66 lines
1.8 KiB
C
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// Copyright 2022 The ChromiumOS Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef VM_TOOLS_SOMMELIER_WEAK_RESOURCE_PTR_H_
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#define VM_TOOLS_SOMMELIER_WEAK_RESOURCE_PTR_H_
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#include "sommelier.h" // NOLINT(build/include_directory)
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#include <algorithm>
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#include <functional>
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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// WeakResourcePtr is a weak pointer for a proxy object (sl_host_foo). It can
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// be useful for objects with events like enter/leave, to keep track of an
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// object provided in the enter event and ensure that it is not used if the
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// client destroys it.
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template <typename SlHostType>
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class WeakResourcePtr {
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public:
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WeakResourcePtr() {
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wl_list_init(&destroy_listener_.link);
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destroy_listener_.notify = ResourceDestroyed;
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}
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~WeakResourcePtr() { wl_list_remove(&destroy_listener_.link); }
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WeakResourcePtr& operator=(SlHostType* host) {
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if (host == host_)
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return *this;
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Reset();
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if (host) {
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host_ = host;
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wl_resource_add_destroy_listener(host_->resource, &destroy_listener_);
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}
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return *this;
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}
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operator bool() const { return host_; }
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SlHostType* operator->() const { return host_; }
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SlHostType* get() const { return host_; }
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void Reset() {
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host_ = nullptr;
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// Remove the listener
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wl_list_remove(&destroy_listener_.link);
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wl_list_init(&destroy_listener_.link);
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}
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private:
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SlHostType* host_ = nullptr;
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// This is always in an initialized state
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wl_listener destroy_listener_;
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static void ResourceDestroyed(wl_listener* listener, void* data) {
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WeakResourcePtr* ptr;
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ptr = wl_container_of(listener, ptr, destroy_listener_);
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ptr->Reset();
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}
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};
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#endif // VM_TOOLS_SOMMELIER_WEAK_RESOURCE_PTR_H_
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