1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
content / browser / webui / web_ui_managed_interface.h [blame]
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_WEBUI_WEB_UI_MANAGED_INTERFACE_H_
#define CONTENT_BROWSER_WEBUI_WEB_UI_MANAGED_INTERFACE_H_
#include <memory>
#include <utility>
#include "base/memory/raw_ptr.h"
#include "base/supports_user_data.h"
#include "content/common/content_export.h"
#include "content/public/browser/web_ui_controller.h"
#include "content/public/browser/web_ui_managed_interface.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"
#include "mojo/public/cpp/bindings/pending_remote.h"
#include "mojo/public/cpp/bindings/receiver.h"
#include "mojo/public/cpp/bindings/remote.h"
namespace content {
using WebUIManagedInterfaceNoPageHandler = void;
// WebUIManagedInterface is an optional base class for implementing classes
// that interact with Mojo endpoints e.g. implement a Mojo interface or
// communicate with a Mojo Remote.
//
// This class provides automated handling of Mojo endpoint bindings and
// lifetime management. The subclass object is created when Create() is
// called and destroyed when the associated WebUI document is removed or
// navigates away.
//
// To implement interface Foo, use the following code:
// class FooImpl : public WebUIManagedInterface<FooImpl, Foo> { ... }
//
// Additionally, to communiate with remote interface Bar:
// class FooBarImpl : public WebUIManagedInterface<FooBarImpl, Foo, Bar> { ...
// }
//
// To implement no interface but only communicate with a remote interface:
// class Baz : public WebUIManagedInterface<
// Baz,
// WebUIManagedInterfaceNoPageHandler,
// BarObserver> { ... }
//
// TODO(crbug.com/40257252): provide helpers to retrieve InterfaceImpl objects.
template <typename InterfaceImpl, typename PageHandler, typename Page = void>
requires(!std::is_void_v<PageHandler> || !std::is_void_v<Page>)
class WebUIManagedInterface : public WebUIManagedInterfaceBase {
public:
template <typename T = Page>
requires(std::is_void_v<T>)
static void Create(WebUIController* web_ui_controller,
mojo::PendingReceiver<PageHandler> pending_receiver) {
return WebUIManagedInterface::Create(
web_ui_controller, std::move(pending_receiver), mojo::NullRemote());
}
template <typename T = PageHandler>
requires(std::is_void_v<T>)
static void Create(WebUIController* webui_controller,
mojo::PendingRemote<Page> pending_remote) {
return WebUIManagedInterface::Create(webui_controller, mojo::NullReceiver(),
std::move(pending_remote));
}
static void Create(WebUIController* webui_controller,
mojo::PendingReceiver<PageHandler> pending_receiver,
mojo::PendingRemote<Page> pending_remote) {
auto interface_impl = std::make_unique<InterfaceImpl>();
auto* interface_impl_ptr = interface_impl.get();
interface_impl->webui_controller_ = webui_controller;
if constexpr (!std::is_void_v<PageHandler>) {
interface_impl->page_handler_receiver_.emplace(
interface_impl_ptr, std::move(pending_receiver));
}
if constexpr (!std::is_void_v<Page>) {
interface_impl->page_remote_.Bind(std::move(pending_remote));
}
SaveWebUIManagedInterfaceInDocument(webui_controller,
std::move(interface_impl));
interface_impl_ptr->ready_ = true;
interface_impl_ptr->OnReady();
}
// Invoked when Mojo endpoints are bound and ready to use.
// TODO(crbug.com/40257247): Remove this by saving endpoints in an external
// storage before constructing `InterfaceImpl`.
virtual void OnReady() {}
template <typename P = PageHandler>
requires(!std::is_void_v<P>)
mojo::Receiver<PageHandler>& receiver() {
CHECK(ready_) << "Mojo endpoints are not ready. Please use OnReady().";
return page_handler_receiver_.value();
}
template <typename P = Page>
requires(!std::is_void_v<P>)
mojo::Remote<Page>& remote() {
CHECK(ready_) << "Mojo endpoints are not ready. Please use OnReady().";
return page_remote_;
}
WebUIController* webui_controller() {
CHECK(ready_) << "webui_controller() is not ready. Please use OnReady().";
return webui_controller_;
}
private:
bool ready_ = false;
// When `PageHandler` is void, declare an unused bool member variable instead
// of a mojo::Receiver<PageHandler>. This allows us to share the same class
// instead of having three different specializations at the cost of an extra
// bool member.
using PageHandlerReceiverType =
std::conditional_t<std::is_void_v<PageHandler>,
bool,
mojo::Receiver<PageHandler>>;
std::optional<PageHandlerReceiverType> page_handler_receiver_;
// When `Page` is void, declare a unused bool member variable instead of a
// mojo::Remote<PageHandler>. This allows us to share the same class
// instead of having three different specializations at the cost of an extra
// bool member.
using PageRemoteType =
std::conditional_t<std::is_void_v<Page>, bool, mojo::Remote<Page>>;
PageRemoteType page_remote_;
raw_ptr<WebUIController> webui_controller_;
};
} // namespace content
#endif // CONTENT_BROWSER_WEBUI_WEB_UI_MANAGED_INTERFACE_H_