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zserge-webview/webview.h
2020-04-10 18:01:18 +02:00

1228 lines
38 KiB
C

/*
* MIT License
*
* Copyright (c) 2017 Serge Zaitsev
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef WEBVIEW_H
#define WEBVIEW_H
#ifndef WEBVIEW_API
#define WEBVIEW_API extern
#endif
#ifdef __cplusplus
extern "C" {
#endif
typedef void *webview_t;
// Creates a new webview instance. If debug is non-zero - developer tools will
// be enabled (if the platform supports them). Window parameter can be a
// pointer to the native window handle. If it's non-null - then child WebView
// is embedded into the given parent window. Otherwise a new window is created.
// Depending on the platform, a GtkWindow, NSWindow or HWND pointer can be
// passed here.
WEBVIEW_API webview_t webview_create(int debug, void *window);
// Destroys a webview and closes the native window.
WEBVIEW_API void webview_destroy(webview_t w);
// Runs the main loop until it's terminated. After this function exits - you
// must destroy the webview.
WEBVIEW_API void webview_run(webview_t w);
// Stops the main loop. It is safe to call this function from another other
// background thread.
WEBVIEW_API void webview_terminate(webview_t w);
// Posts a function to be executed on the main thread. You normally do not need
// to call this function, unless you want to tweak the native window.
WEBVIEW_API void
webview_dispatch(webview_t w, void (*fn)(webview_t w, void *arg), void *arg);
// Returns a native window handle pointer. When using GTK backend the pointer
// is GtkWindow pointer, when using Cocoa backend the pointer is NSWindow
// pointer, when using Win32 backend the pointer is HWND pointer.
WEBVIEW_API void *webview_get_window(webview_t w);
// Updates the title of the native window. Must be called from the UI thread.
WEBVIEW_API void webview_set_title(webview_t w, const char *title);
// Window size hints
#define WEBVIEW_HINT_NONE 0 // Width and height are default size
#define WEBVIEW_HINT_MIN 1 // Width and height are minimum bounds
#define WEBVIEW_HINT_MAX 2 // Width and height are maximum bounds
#define WEBVIEW_HINT_FIXED 3 // Window size can not be changed by a user
// Updates native window size. See WEBVIEW_HINT constants.
WEBVIEW_API void webview_set_size(webview_t w, int width, int height,
int hints);
// Navigates webview to the given URL. URL may be a data URI, i.e.
// "data:text/text,<html>...</html>". It is often ok not to url-encode it
// properly, webview will re-encode it for you.
WEBVIEW_API void webview_navigate(webview_t w, const char *url);
// Injects JavaScript code at the initialization of the new page. Every time
// the webview will open a the new page - this initialization code will be
// executed. It is guaranteed that code is executed before window.onload.
WEBVIEW_API void webview_init(webview_t w, const char *js);
// Evaluates arbitrary JavaScript code. Evaluation happens asynchronously, also
// the result of the expression is ignored. Use RPC bindings if you want to
// receive notifications about the results of the evaluation.
WEBVIEW_API void webview_eval(webview_t w, const char *js);
// Binds a native C callback so that it will appear under the given name as a
// global JavaScript function. Internally it uses webview_init(). Callback
// receives a request string and a user-provided argument pointer. Request
// string is a JSON array of all the arguments passed to the JavaScript
// function.
WEBVIEW_API void webview_bind(webview_t w, const char *name,
void (*fn)(const char *seq, const char *req,
void *arg),
void *arg);
// Allows to return a value from the native binding. Original request pointer
// must be provided to help internal RPC engine match requests with responses.
// If status is zero - result is expected to be a valid JSON result value.
// If status is not zero - result is an error JSON object.
WEBVIEW_API void webview_return(webview_t w, const char *seq, int status,
const char *result);
#ifdef __cplusplus
}
#endif
#ifndef WEBVIEW_HEADER
#if !defined(WEBVIEW_GTK) && !defined(WEBVIEW_COCOA) && !defined(WEBVIEW_EDGE)
#if defined(__linux__)
#define WEBVIEW_GTK
#elif defined(__APPLE__)
#define WEBVIEW_COCOA
#elif defined(_WIN32)
#define WEBVIEW_EDGE
#else
#error "please, specify webview backend"
#endif
#endif
#include <atomic>
#include <functional>
#include <future>
#include <map>
#include <string>
#include <utility>
#include <vector>
#include <cstring>
namespace webview {
using dispatch_fn_t = std::function<void()>;
inline std::string url_encode(const std::string s) {
std::string encoded;
for (unsigned int i = 0; i < s.length(); i++) {
auto c = s[i];
if (isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') {
encoded = encoded + c;
} else {
char hex[4];
snprintf(hex, sizeof(hex), "%%%02x", c);
encoded = encoded + hex;
}
}
return encoded;
}
inline std::string url_decode(const std::string s) {
std::string decoded;
for (unsigned int i = 0; i < s.length(); i++) {
if (s[i] == '%') {
int n;
n = std::stoul(s.substr(i + 1, 2), nullptr, 16);
decoded = decoded + static_cast<char>(n);
i = i + 2;
} else if (s[i] == '+') {
decoded = decoded + ' ';
} else {
decoded = decoded + s[i];
}
}
return decoded;
}
inline std::string html_from_uri(const std::string s) {
if (s.substr(0, 15) == "data:text/html,") {
return url_decode(s.substr(15));
}
return "";
}
inline int json_parse_c(const char *s, size_t sz, const char *key, size_t keysz,
const char **value, size_t *valuesz) {
enum {
JSON_STATE_VALUE,
JSON_STATE_LITERAL,
JSON_STATE_STRING,
JSON_STATE_ESCAPE,
JSON_STATE_UTF8
} state = JSON_STATE_VALUE;
const char *k = NULL;
int index = 1;
int depth = 0;
int utf8_bytes = 0;
if (key == NULL) {
index = keysz;
keysz = 0;
}
*value = NULL;
*valuesz = 0;
for (; sz > 0; s++, sz--) {
enum {
JSON_ACTION_NONE,
JSON_ACTION_START,
JSON_ACTION_END,
JSON_ACTION_START_STRUCT,
JSON_ACTION_END_STRUCT
} action = JSON_ACTION_NONE;
unsigned char c = *s;
switch (state) {
case JSON_STATE_VALUE:
if (c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == ',' ||
c == ':') {
continue;
} else if (c == '"') {
action = JSON_ACTION_START;
state = JSON_STATE_STRING;
} else if (c == '{' || c == '[') {
action = JSON_ACTION_START_STRUCT;
} else if (c == '}' || c == ']') {
action = JSON_ACTION_END_STRUCT;
} else if (c == 't' || c == 'f' || c == 'n' || c == '-' ||
(c >= '0' && c <= '9')) {
action = JSON_ACTION_START;
state = JSON_STATE_LITERAL;
} else {
return -1;
}
break;
case JSON_STATE_LITERAL:
if (c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == ',' ||
c == ']' || c == '}' || c == ':') {
state = JSON_STATE_VALUE;
s--;
sz++;
action = JSON_ACTION_END;
} else if (c < 32 || c > 126) {
return -1;
} // fallthrough
case JSON_STATE_STRING:
if (c < 32 || (c > 126 && c < 192)) {
return -1;
} else if (c == '"') {
action = JSON_ACTION_END;
state = JSON_STATE_VALUE;
} else if (c == '\\') {
state = JSON_STATE_ESCAPE;
} else if (c >= 192 && c < 224) {
utf8_bytes = 1;
state = JSON_STATE_UTF8;
} else if (c >= 224 && c < 240) {
utf8_bytes = 2;
state = JSON_STATE_UTF8;
} else if (c >= 240 && c < 247) {
utf8_bytes = 3;
state = JSON_STATE_UTF8;
} else if (c >= 128 && c < 192) {
return -1;
}
break;
case JSON_STATE_ESCAPE:
if (c == '"' || c == '\\' || c == '/' || c == 'b' || c == 'f' ||
c == 'n' || c == 'r' || c == 't' || c == 'u') {
state = JSON_STATE_STRING;
} else {
return -1;
}
break;
case JSON_STATE_UTF8:
if (c < 128 || c > 191) {
return -1;
}
utf8_bytes--;
if (utf8_bytes == 0) {
state = JSON_STATE_STRING;
}
break;
default:
return -1;
}
if (action == JSON_ACTION_END_STRUCT) {
depth--;
}
if (depth == 1) {
if (action == JSON_ACTION_START || action == JSON_ACTION_START_STRUCT) {
if (index == 0) {
*value = s;
} else if (keysz > 0 && index == 1) {
k = s;
} else {
index--;
}
} else if (action == JSON_ACTION_END ||
action == JSON_ACTION_END_STRUCT) {
if (*value != NULL && index == 0) {
*valuesz = (size_t)(s + 1 - *value);
return 0;
} else if (keysz > 0 && k != NULL) {
if (keysz == (size_t)(s - k - 1) && memcmp(key, k + 1, keysz) == 0) {
index = 0;
} else {
index = 2;
}
k = NULL;
}
}
}
if (action == JSON_ACTION_START_STRUCT) {
depth++;
}
}
return -1;
}
inline std::string json_escape(std::string s) {
// TODO: implement
return '"' + s + '"';
}
inline int json_unescape(const char *s, size_t n, char *out) {
int r = 0;
if (*s++ != '"') {
return -1;
}
while (n > 2) {
char c = *s;
if (c == '\\') {
s++;
n--;
switch (*s) {
case 'b':
c = '\b';
break;
case 'f':
c = '\f';
break;
case 'n':
c = '\n';
break;
case 'r':
c = '\r';
break;
case 't':
c = '\t';
break;
case '\\':
c = '\\';
break;
case '/':
c = '/';
break;
case '\"':
c = '\"';
break;
default: // TODO: support unicode decoding
return -1;
}
}
if (out != NULL) {
*out++ = c;
}
s++;
n--;
r++;
}
if (*s != '"') {
return -1;
}
if (out != NULL) {
*out = '\0';
}
return r;
}
inline std::string json_parse(const std::string s, const std::string key,
const int index) {
const char *value;
size_t value_sz;
if (key == "") {
json_parse_c(s.c_str(), s.length(), nullptr, index, &value, &value_sz);
} else {
json_parse_c(s.c_str(), s.length(), key.c_str(), key.length(), &value,
&value_sz);
}
if (value != nullptr) {
if (value[0] != '"') {
return std::string(value, value_sz);
}
int n = json_unescape(value, value_sz, nullptr);
if (n > 0) {
char *decoded = new char[n + 1];
json_unescape(value, value_sz, decoded);
std::string result(decoded, n);
delete[] decoded;
return result;
}
}
return "";
}
} // namespace webview
#if defined(WEBVIEW_GTK)
//
// ====================================================================
//
// This implementation uses webkit2gtk backend. It requires gtk+3.0 and
// webkit2gtk-4.0 libraries. Proper compiler flags can be retrieved via:
//
// pkg-config --cflags --libs gtk+-3.0 webkit2gtk-4.0
//
// ====================================================================
//
#include <JavaScriptCore/JavaScript.h>
#include <gtk/gtk.h>
#include <webkit2/webkit2.h>
namespace webview {
class gtk_webkit_engine {
public:
gtk_webkit_engine(bool debug, void *window)
: m_window(static_cast<GtkWidget *>(window)) {
gtk_init_check(0, NULL);
m_window = static_cast<GtkWidget *>(window);
if (m_window == nullptr) {
m_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
}
g_signal_connect(G_OBJECT(m_window), "destroy",
G_CALLBACK(+[](GtkWidget *, gpointer arg) {
static_cast<gtk_webkit_engine *>(arg)->terminate();
}),
this);
// Initialize webview widget
m_webview = webkit_web_view_new();
WebKitUserContentManager *manager =
webkit_web_view_get_user_content_manager(WEBKIT_WEB_VIEW(m_webview));
g_signal_connect(manager, "script-message-received::external",
G_CALLBACK(+[](WebKitUserContentManager *,
WebKitJavascriptResult *r, gpointer arg) {
auto *w = static_cast<gtk_webkit_engine *>(arg);
#if WEBKIT_MAJOR_VERSION >= 2 && WEBKIT_MINOR_VERSION >= 22
JSCValue *value =
webkit_javascript_result_get_js_value(r);
char *s = jsc_value_to_string(value);
#else
JSGlobalContextRef ctx =
webkit_javascript_result_get_global_context(r);
JSValueRef value = webkit_javascript_result_get_value(r);
JSStringRef js = JSValueToStringCopy(ctx, value, NULL);
size_t n = JSStringGetMaximumUTF8CStringSize(js);
char *s = g_new(char, n);
JSStringGetUTF8CString(js, s, n);
JSStringRelease(js);
#endif
w->on_message(s);
g_free(s);
}),
this);
webkit_user_content_manager_register_script_message_handler(manager,
"external");
init("window.external={invoke:function(s){window.webkit.messageHandlers."
"external.postMessage(s);}}");
gtk_container_add(GTK_CONTAINER(m_window), GTK_WIDGET(m_webview));
gtk_widget_grab_focus(GTK_WIDGET(m_webview));
if (debug) {
WebKitSettings *settings =
webkit_web_view_get_settings(WEBKIT_WEB_VIEW(m_webview));
webkit_settings_set_enable_write_console_messages_to_stdout(settings,
true);
webkit_settings_set_enable_developer_extras(settings, true);
}
gtk_widget_show_all(m_window);
}
void *window() { return (void *)m_window; }
void run() { gtk_main(); }
void terminate() { gtk_main_quit(); }
void dispatch(std::function<void()> f) {
g_idle_add_full(G_PRIORITY_HIGH_IDLE, (GSourceFunc)([](void *f) -> int {
(*static_cast<dispatch_fn_t *>(f))();
return G_SOURCE_REMOVE;
}),
new std::function<void()>(f),
[](void *f) { delete static_cast<dispatch_fn_t *>(f); });
}
void set_title(const std::string title) {
gtk_window_set_title(GTK_WINDOW(m_window), title.c_str());
}
void set_size(int width, int height, int hints) {
gtk_window_set_resizable(GTK_WINDOW(m_window), hints != WEBVIEW_HINT_FIXED);
if (hints == WEBVIEW_HINT_NONE) {
gtk_window_resize(GTK_WINDOW(m_window), width, height);
} else if (hints == WEBVIEW_HINT_FIXED) {
gtk_widget_set_size_request(m_window, width, height);
} else {
GdkGeometry g;
g.min_width = g.max_width = width;
g.min_height = g.max_height = height;
GdkWindowHints h =
(hints == WEBVIEW_HINT_MIN ? GDK_HINT_MIN_SIZE : GDK_HINT_MAX_SIZE);
// This defines either MIN_SIZE, or MAX_SIZE, but not both:
gtk_window_set_geometry_hints(GTK_WINDOW(m_window), nullptr, &g, h);
}
}
void navigate(const std::string url) {
webkit_web_view_load_uri(WEBKIT_WEB_VIEW(m_webview), url.c_str());
}
void init(const std::string js) {
WebKitUserContentManager *manager =
webkit_web_view_get_user_content_manager(WEBKIT_WEB_VIEW(m_webview));
webkit_user_content_manager_add_script(
manager, webkit_user_script_new(
js.c_str(), WEBKIT_USER_CONTENT_INJECT_TOP_FRAME,
WEBKIT_USER_SCRIPT_INJECT_AT_DOCUMENT_START, NULL, NULL));
}
void eval(const std::string js) {
webkit_web_view_run_javascript(WEBKIT_WEB_VIEW(m_webview), js.c_str(), NULL,
NULL, NULL);
}
private:
virtual void on_message(const std::string msg) = 0;
GtkWidget *m_window;
GtkWidget *m_webview;
};
using browser_engine = gtk_webkit_engine;
} // namespace webview
#elif defined(WEBVIEW_COCOA)
//
// ====================================================================
//
// This implementation uses Cocoa WKWebView backend on macOS. It is
// written using ObjC runtime and uses WKWebView class as a browser runtime.
// You should pass "-framework Webkit" flag to the compiler.
//
// ====================================================================
//
#define OBJC_OLD_DISPATCH_PROTOTYPES 1
#include <CoreGraphics/CoreGraphics.h>
#include <objc/objc-runtime.h>
#define NSBackingStoreBuffered 2
#define NSWindowStyleMaskResizable 8
#define NSWindowStyleMaskMiniaturizable 4
#define NSWindowStyleMaskTitled 1
#define NSWindowStyleMaskClosable 2
#define NSApplicationActivationPolicyRegular 0
#define WKUserScriptInjectionTimeAtDocumentStart 0
namespace webview {
// Helpers to avoid too much typing
id operator"" _cls(const char *s, std::size_t) { return (id)objc_getClass(s); }
SEL operator"" _sel(const char *s, std::size_t) { return sel_registerName(s); }
id operator"" _str(const char *s, std::size_t) {
return objc_msgSend("NSString"_cls, "stringWithUTF8String:"_sel, s);
}
class cocoa_wkwebview_engine {
public:
cocoa_wkwebview_engine(bool debug, void *window) {
// Application
id app = objc_msgSend("NSApplication"_cls, "sharedApplication"_sel);
objc_msgSend(app, "setActivationPolicy:"_sel,
NSApplicationActivationPolicyRegular);
// Delegate
auto cls = objc_allocateClassPair((Class) "NSResponder"_cls, "AppDelegate", 0);
class_addProtocol(cls, objc_getProtocol("NSTouchBarProvider"));
class_addMethod(cls, "applicationShouldTerminateAfterLastWindowClosed:"_sel,
(IMP)(+[](id, SEL, id) -> BOOL { return 1; }), "c@:@");
class_addMethod(cls, "userContentController:didReceiveScriptMessage:"_sel,
(IMP)(+[](id self, SEL, id, id msg) {
auto w =
(cocoa_wkwebview_engine *)objc_getAssociatedObject(
self, "webview");
w->on_message((const char *)objc_msgSend(
objc_msgSend(msg, "body"_sel), "UTF8String"_sel));
}),
"v@:@@");
objc_registerClassPair(cls);
auto delegate = objc_msgSend((id)cls, "new"_sel);
objc_setAssociatedObject(delegate, "webview", (id)this,
OBJC_ASSOCIATION_ASSIGN);
objc_msgSend(app, sel_registerName("setDelegate:"), delegate);
// Main window
if (window == nullptr) {
m_window = objc_msgSend("NSWindow"_cls, "alloc"_sel);
m_window = objc_msgSend(
m_window, "initWithContentRect:styleMask:backing:defer:"_sel,
CGRectMake(0, 0, 0, 0), 0, NSBackingStoreBuffered, 0);
} else {
m_window = (id)window;
}
// Webview
auto config = objc_msgSend("WKWebViewConfiguration"_cls, "new"_sel);
m_manager = objc_msgSend(config, "userContentController"_sel);
m_webview = objc_msgSend("WKWebView"_cls, "alloc"_sel);
if (debug) {
objc_msgSend(objc_msgSend(config, "preferences"_sel),
"setValue:forKey:"_sel,
objc_msgSend("NSNumber"_cls, "numberWithBool:"_sel, 1),
"developerExtrasEnabled"_str);
}
objc_msgSend(m_webview, "initWithFrame:configuration:"_sel,
CGRectMake(0, 0, 0, 0), config);
objc_msgSend(m_manager, "addScriptMessageHandler:name:"_sel, delegate,
"external"_str);
init(R"script(
window.external = {
invoke: function(s) {
window.webkit.messageHandlers.external.postMessage(s);
},
};
)script");
objc_msgSend(m_window, "setContentView:"_sel, m_webview);
objc_msgSend(m_window, "makeKeyAndOrderFront:"_sel, nullptr);
}
~cocoa_wkwebview_engine() { close(); }
void *window() { return (void *)m_window; }
void terminate() {
close();
objc_msgSend("NSApp"_cls, "terminate:"_sel, nullptr);
}
void run() {
id app = objc_msgSend("NSApplication"_cls, "sharedApplication"_sel);
dispatch([&]() { objc_msgSend(app, "activateIgnoringOtherApps:"_sel, 1); });
objc_msgSend(app, "run"_sel);
}
void dispatch(std::function<void()> f) {
dispatch_async_f(dispatch_get_main_queue(), new dispatch_fn_t(f),
(dispatch_function_t)([](void *arg) {
auto f = static_cast<dispatch_fn_t *>(arg);
(*f)();
delete f;
}));
}
void set_title(const std::string title) {
objc_msgSend(m_window, "setTitle:"_sel,
objc_msgSend("NSString"_cls, "stringWithUTF8String:"_sel,
title.c_str()));
}
void set_size(int width, int height, int hints) {
auto style = NSWindowStyleMaskTitled | NSWindowStyleMaskClosable |
NSWindowStyleMaskMiniaturizable;
if (hints != WEBVIEW_HINT_FIXED) {
style = style | NSWindowStyleMaskResizable;
}
objc_msgSend(m_window, "setStyleMask:"_sel, style);
struct {
CGFloat width;
CGFloat height;
} size;
if (hints == WEBVIEW_HINT_MIN) {
size.width = width;
size.height = height;
objc_msgSend(m_window, "setContentMinSize:"_sel, size);
} else if (hints == WEBVIEW_HINT_MAX) {
size.width = width;
size.height = height;
objc_msgSend(m_window, "setContentMaxSize:"_sel, size);
} else {
objc_msgSend(m_window, "setFrame:display:animate:"_sel,
CGRectMake(0, 0, width, height), 1, 0);
}
}
void navigate(const std::string url) {
auto nsurl = objc_msgSend(
"NSURL"_cls, "URLWithString:"_sel,
objc_msgSend("NSString"_cls, "stringWithUTF8String:"_sel, url.c_str()));
objc_msgSend(
m_webview, "loadRequest:"_sel,
objc_msgSend("NSURLRequest"_cls, "requestWithURL:"_sel, nsurl));
}
void init(const std::string js) {
objc_msgSend(
m_manager, "addUserScript:"_sel,
objc_msgSend(objc_msgSend("WKUserScript"_cls, "alloc"_sel),
"initWithSource:injectionTime:forMainFrameOnly:"_sel,
objc_msgSend("NSString"_cls, "stringWithUTF8String:"_sel,
js.c_str()),
WKUserScriptInjectionTimeAtDocumentStart, 1));
}
void eval(const std::string js) {
objc_msgSend(
m_webview, "evaluateJavaScript:completionHandler:"_sel,
objc_msgSend("NSString"_cls, "stringWithUTF8String:"_sel, js.c_str()),
nullptr);
}
private:
virtual void on_message(const std::string msg) = 0;
void close() { objc_msgSend(m_window, "close"_sel); }
id m_window;
id m_webview;
id m_manager;
};
using browser_engine = cocoa_wkwebview_engine;
} // namespace webview
#elif defined(WEBVIEW_EDGE)
//
// ====================================================================
//
// This implementation uses Win32 API to create a native window. It can
// use either EdgeHTML or Edge/Chromium backend as a browser engine.
//
// ====================================================================
//
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#pragma comment(lib, "user32.lib")
// EdgeHTML headers and libs
#include <objbase.h>
#include <winrt/Windows.Foundation.h>
#include <winrt/Windows.Web.UI.Interop.h>
#pragma comment(lib, "windowsapp")
// Edge/Chromium headers and libs
#include "webview2.h"
#pragma comment(lib, "ole32.lib")
#pragma comment(lib, "oleaut32.lib")
namespace webview {
using msg_cb_t = std::function<void(const std::string)>;
// Common interface for EdgeHTML and Edge/Chromium
class browser {
public:
virtual ~browser() = default;
virtual bool embed(HWND, bool, msg_cb_t) = 0;
virtual void navigate(const std::string url) = 0;
virtual void eval(const std::string js) = 0;
virtual void init(const std::string js) = 0;
virtual void resize(HWND) = 0;
};
//
// EdgeHTML browser engine
//
using namespace winrt;
using namespace Windows::Foundation;
using namespace Windows::Web::UI;
using namespace Windows::Web::UI::Interop;
class edge_html : public browser {
public:
bool embed(HWND wnd, bool debug, msg_cb_t cb) override {
init_apartment(winrt::apartment_type::single_threaded);
auto process = WebViewControlProcess();
auto op = process.CreateWebViewControlAsync(reinterpret_cast<int64_t>(wnd),
Rect());
if (op.Status() != AsyncStatus::Completed) {
handle h(CreateEvent(nullptr, false, false, nullptr));
op.Completed([h = h.get()](auto, auto) { SetEvent(h); });
HANDLE hs[] = {h.get()};
DWORD i;
CoWaitForMultipleHandles(COWAIT_DISPATCH_WINDOW_MESSAGES |
COWAIT_DISPATCH_CALLS |
COWAIT_INPUTAVAILABLE,
INFINITE, 1, hs, &i);
}
m_webview = op.GetResults();
m_webview.Settings().IsScriptNotifyAllowed(true);
m_webview.IsVisible(true);
m_webview.ScriptNotify([=](auto const &sender, auto const &args) {
std::string s = winrt::to_string(args.Value());
cb(s.c_str());
});
m_webview.NavigationStarting([=](auto const &sender, auto const &args) {
m_webview.AddInitializeScript(winrt::to_hstring(init_js));
});
init("window.external.invoke = s => window.external.notify(s)");
return true;
}
void navigate(const std::string url) override {
std::string html = html_from_uri(url);
if (html != "") {
m_webview.NavigateToString(winrt::to_hstring(html));
} else {
Uri uri(winrt::to_hstring(url));
m_webview.Navigate(uri);
}
}
void init(const std::string js) override {
init_js = init_js + "(function(){" + js + "})();";
}
void eval(const std::string js) override {
m_webview.InvokeScriptAsync(
L"eval", single_threaded_vector<hstring>({winrt::to_hstring(js)}));
}
void resize(HWND wnd) override {
if (m_webview == nullptr) {
return;
}
RECT r;
GetClientRect(wnd, &r);
Rect bounds(r.left, r.top, r.right - r.left, r.bottom - r.top);
m_webview.Bounds(bounds);
}
private:
WebViewControl m_webview = nullptr;
std::string init_js = "";
};
//
// Edge/Chromium browser engine
//
class edge_chromium : public browser {
public:
bool embed(HWND wnd, bool debug, msg_cb_t cb) override {
CoInitializeEx(nullptr, 0);
std::atomic_flag flag = ATOMIC_FLAG_INIT;
flag.test_and_set();
HRESULT res = CreateWebView2EnvironmentWithDetails(
nullptr, nullptr, nullptr,
new webview2_com_handler(wnd, [&](IWebView2WebView *webview) {
m_webview = webview;
flag.clear();
}));
if (res != S_OK) {
CoUninitialize();
return false;
}
MSG msg = {};
while (flag.test_and_set() && GetMessage(&msg, NULL, 0, 0)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
init("window.external={invoke:s=>window.chrome.webview.postMessage(s)}");
return true;
}
void resize(HWND wnd) override {
if (m_webview == nullptr) {
return;
}
RECT bounds;
GetClientRect(wnd, &bounds);
m_webview->put_Bounds(bounds);
}
void navigate(const std::string url) override {
auto wurl = to_lpwstr(url);
m_webview->Navigate(wurl);
delete[] wurl;
}
void init(const std::string js) override {
LPCWSTR wjs = to_lpwstr(js);
m_webview->AddScriptToExecuteOnDocumentCreated(wjs, nullptr);
delete[] wjs;
}
void eval(const std::string js) override {
LPCWSTR wjs = to_lpwstr(js);
m_webview->ExecuteScript(wjs, nullptr);
delete[] wjs;
}
private:
LPWSTR to_lpwstr(const std::string s) {
int n = MultiByteToWideChar(CP_UTF8, 0, s.c_str(), -1, NULL, 0);
wchar_t *ws = new wchar_t[n];
MultiByteToWideChar(CP_UTF8, 0, s.c_str(), -1, ws, n);
return ws;
}
IWebView2WebView *m_webview = nullptr;
class webview2_com_handler
: public IWebView2CreateWebView2EnvironmentCompletedHandler,
public IWebView2CreateWebViewCompletedHandler {
using webview2_com_handler_cb_t = std::function<void(IWebView2WebView *)>;
public:
webview2_com_handler(HWND hwnd, webview2_com_handler_cb_t cb)
: m_window(hwnd), m_cb(cb) {}
ULONG STDMETHODCALLTYPE AddRef() { return 1; }
ULONG STDMETHODCALLTYPE Release() { return 1; }
HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, LPVOID *ppv) {
return S_OK;
}
HRESULT STDMETHODCALLTYPE Invoke(HRESULT res, IWebView2Environment *env) {
env->CreateWebView(m_window, this);
return S_OK;
}
HRESULT STDMETHODCALLTYPE Invoke(HRESULT res, IWebView2WebView *webview) {
webview->AddRef();
m_cb(webview);
return S_OK;
}
private:
HWND m_window;
webview2_com_handler_cb_t m_cb;
};
};
class win32_edge_engine {
public:
win32_edge_engine(bool debug, void *window) {
if (window == nullptr) {
WNDCLASSEX wc;
ZeroMemory(&wc, sizeof(WNDCLASSEX));
wc.cbSize = sizeof(WNDCLASSEX);
wc.hInstance = GetModuleHandle(nullptr);
wc.lpszClassName = "webview";
wc.lpfnWndProc =
(WNDPROC)(+[](HWND hwnd, UINT msg, WPARAM wp, LPARAM lp) -> int {
auto w = (win32_edge_engine *)GetWindowLongPtr(hwnd, GWLP_USERDATA);
switch (msg) {
case WM_SIZE:
w->m_browser->resize(hwnd);
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
w->terminate();
break;
case WM_GETMINMAXINFO: {
auto lpmmi = (LPMINMAXINFO)lp;
if (w == nullptr) {
return 0;
}
if (w->m_maxsz.x > 0 && w->m_maxsz.y > 0) {
lpmmi->ptMaxSize = w->m_maxsz;
lpmmi->ptMaxTrackSize = w->m_maxsz;
}
if (w->m_minsz.x > 0 && w->m_minsz.y > 0) {
lpmmi->ptMinTrackSize = w->m_minsz;
}
} break;
default:
return DefWindowProc(hwnd, msg, wp, lp);
}
return 0;
});
RegisterClassEx(&wc);
m_window = CreateWindow("webview", "", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT,
CW_USEDEFAULT, 640, 480, nullptr, nullptr,
GetModuleHandle(nullptr), nullptr);
SetWindowLongPtr(m_window, GWLP_USERDATA, (LONG_PTR)this);
} else {
m_window = *(static_cast<HWND *>(window));
}
ShowWindow(m_window, SW_SHOW);
UpdateWindow(m_window);
SetFocus(m_window);
auto cb =
std::bind(&win32_edge_engine::on_message, this, std::placeholders::_1);
if (!m_browser->embed(m_window, debug, cb)) {
m_browser = std::make_unique<webview::edge_html>();
m_browser->embed(m_window, debug, cb);
}
m_browser->resize(m_window);
}
void run() {
MSG msg;
BOOL res;
while ((res = GetMessage(&msg, nullptr, 0, 0)) != -1) {
if (msg.hwnd) {
TranslateMessage(&msg);
DispatchMessage(&msg);
continue;
}
if (msg.message == WM_APP) {
auto f = (dispatch_fn_t *)(msg.lParam);
(*f)();
delete f;
} else if (msg.message == WM_QUIT) {
return;
}
}
}
void *window() { return (void *)m_window; }
void terminate() { PostQuitMessage(0); }
void dispatch(dispatch_fn_t f) {
PostThreadMessage(m_main_thread, WM_APP, 0, (LPARAM) new dispatch_fn_t(f));
}
void set_title(const std::string title) {
SetWindowText(m_window, title.c_str());
}
void set_size(int width, int height, int hints) {
auto style = GetWindowLong(m_window, GWL_STYLE);
if (hints == WEBVIEW_HINT_FIXED) {
style &= ~(WS_THICKFRAME | WS_MAXIMIZEBOX);
} else {
style |= (WS_THICKFRAME | WS_MAXIMIZEBOX);
}
SetWindowLong(m_window, GWL_STYLE, style);
if (hints == WEBVIEW_HINT_MAX) {
m_maxsz.x = width;
m_maxsz.y = height;
} else if (hints == WEBVIEW_HINT_MIN) {
m_minsz.x = width;
m_minsz.y = height;
} else {
RECT r;
r.left = r.top = 0;
r.right = width;
r.bottom = height;
AdjustWindowRect(&r, WS_OVERLAPPEDWINDOW, 0);
SetWindowPos(
m_window, NULL, r.left, r.top, r.right - r.left, r.bottom - r.top,
SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOMOVE | SWP_FRAMECHANGED);
m_browser->resize(m_window);
}
}
void navigate(const std::string url) { m_browser->navigate(url); }
void eval(const std::string js) { m_browser->eval(js); }
void init(const std::string js) { m_browser->init(js); }
private:
virtual void on_message(const std::string msg) = 0;
HWND m_window;
POINT m_minsz;
POINT m_maxsz;
DWORD m_main_thread = GetCurrentThreadId();
std::unique_ptr<webview::browser> m_browser =
std::make_unique<webview::edge_chromium>();
};
using browser_engine = win32_edge_engine;
} // namespace webview
#endif /* WEBVIEW_GTK, WEBVIEW_COCOA, WEBVIEW_EDGE */
namespace webview {
class webview : public browser_engine {
public:
webview(bool debug = false, void *wnd = nullptr)
: browser_engine(debug, wnd) {}
void navigate(const std::string url) {
if (url == "") {
browser_engine::navigate("data:text/html," +
url_encode("<html><body>Hello</body></html>"));
return;
}
std::string html = html_from_uri(url);
if (html != "") {
browser_engine::navigate("data:text/html," + url_encode(html));
} else {
browser_engine::navigate(url);
}
}
using binding_t = std::function<void(std::string, std::string, void *)>;
using binding_ctx_t = std::pair<binding_t *, void *>;
using sync_binding_t = std::function<std::string(std::string)>;
using sync_binding_ctx_t = std::pair<webview *, sync_binding_t>;
void bind(const std::string name, sync_binding_t fn) {
bind(name,
[](std::string seq, std::string req, void *arg) {
auto pair = static_cast<sync_binding_ctx_t *>(arg);
pair->first->resolve(seq, 0, pair->second(req));
},
new sync_binding_ctx_t(this, fn));
}
void bind(const std::string name, binding_t f, void *arg) {
auto js = "(function() { var name = '" + name + "';" + R"(
var RPC = window._rpc = (window._rpc || {nextSeq: 1});
window[name] = function() {
var seq = RPC.nextSeq++;
var promise = new Promise(function(resolve, reject) {
RPC[seq] = {
resolve: resolve,
reject: reject,
};
});
window.external.invoke(JSON.stringify({
id: seq,
method: name,
params: Array.prototype.slice.call(arguments),
}));
return promise;
}
})())";
init(js);
bindings[name] = new binding_ctx_t(new binding_t(f), arg);
}
void resolve(const std::string seq, int status, const std::string result) {
dispatch([=]() {
if (status == 0) {
eval("window._rpc[" + seq + "].resolve(" + result + "); window._rpc[" +
seq + "] = undefined");
} else {
eval("window._rpc[" + seq + "].reject(" + result + "); window._rpc[" +
seq + "] = undefined");
}
});
}
private:
void on_message(const std::string msg) {
auto seq = json_parse(msg, "id", 0);
auto name = json_parse(msg, "method", 0);
auto args = json_parse(msg, "params", 0);
if (bindings.find(name) == bindings.end()) {
return;
}
auto fn = bindings[name];
(*fn->first)(seq, args, fn->second);
}
std::map<std::string, binding_ctx_t *> bindings;
};
} // namespace webview
WEBVIEW_API webview_t webview_create(int debug, void *wnd) {
return new webview::webview(debug, wnd);
}
WEBVIEW_API void webview_destroy(webview_t w) {
delete static_cast<webview::webview *>(w);
}
WEBVIEW_API void webview_run(webview_t w) {
static_cast<webview::webview *>(w)->run();
}
WEBVIEW_API void webview_terminate(webview_t w) {
static_cast<webview::webview *>(w)->terminate();
}
WEBVIEW_API void webview_dispatch(webview_t w, void (*fn)(webview_t, void *),
void *arg) {
static_cast<webview::webview *>(w)->dispatch([=]() { fn(w, arg); });
}
WEBVIEW_API void *webview_get_window(webview_t w) {
return static_cast<webview::webview *>(w)->window();
}
WEBVIEW_API void webview_set_title(webview_t w, const char *title) {
static_cast<webview::webview *>(w)->set_title(title);
}
WEBVIEW_API void webview_set_size(webview_t w, int width, int height,
int hints) {
static_cast<webview::webview *>(w)->set_size(width, height, hints);
}
WEBVIEW_API void webview_navigate(webview_t w, const char *url) {
static_cast<webview::webview *>(w)->navigate(url);
}
WEBVIEW_API void webview_init(webview_t w, const char *js) {
static_cast<webview::webview *>(w)->init(js);
}
WEBVIEW_API void webview_eval(webview_t w, const char *js) {
static_cast<webview::webview *>(w)->eval(js);
}
WEBVIEW_API void webview_bind(webview_t w, const char *name,
void (*fn)(const char *seq, const char *req,
void *arg),
void *arg) {
static_cast<webview::webview *>(w)->bind(
name,
[=](std::string seq, std::string req, void *arg) {
fn(seq.c_str(), req.c_str(), arg);
},
arg);
}
WEBVIEW_API void webview_return(webview_t w, const char *seq, int status,
const char *result) {
static_cast<webview::webview *>(w)->resolve(seq, status, result);
}
#endif /* WEBVIEW_HEADER */
#endif /* WEBVIEW_H */