Add xwidget support for macOS

Co-authored-by: Jaesup Kwak <veshboo@gmail.com>

* configure.ac: Allow '--with-xwidgets' for "${NS_IMPL_COCOA}".
* etc/NEWS: Mention new feature.
* etc/TODO: Remove done TODO to implement xwidget in NeXTstep port.
* lisp/xwidget.el (xwidget-webkit-clone-and-split-below)
(xwidget-webkit-clone-and-split-right): New procedures.
(xwidget-webkit-callback): Remove call to
'xwidget-webkit-adjust-size-to-window' as adjusting xwidget size is
handled in 'x_draw_xwidget_glyph_string'.
(xwidget-webkit-enable-plugins): New variable.
* nextstep/templates/Info.plist.in: Add 'NSAppTransportSecurity'.
* src/Makefile.in: Add nsxwidget.o for compilation.
* src/emacs.c (main): Move conditional call to 'syms_of_xwidget'.
* src/nsterm.m (ns_draw_glyph_string): Add case for 'XWIDGET_GLYPH'.
(note_mouse_movement mouseMoved): Make it easy to resize window by
dragging mode-line or vertical separator adjacent to large glyph.
* src/nsxwidget.h src/nsxwidget.m: Newly added files, xwidget webkit
backend for macOS Cocoa.
* src/xwidget.c (Fmake_xwidget, xwidget_init_view)
(x_draw_xwidget_glyph_string, xwidget_is_web_view)
(Fxwidget_webkit_goto_uri, Fxwidget_webkit_zoom, Fxwidget_resize)
(Fxwidget_size_request, Fdelete_xwidget_view, xwidget_end_redisplay)
(kill_buffer_xwidgets): Add macOS Cocoa specific functions and code
with 'NS_IMPL_COCOA' and guard GTK specific functions and code with
'USE_GTK'.
(x_draw_xwidget_glyph_string): Handle adjusting xwidget size.
* src/xwidget.h (xwidget, xwidget_view): Add macOS Cocoa specific
fields with 'NS_IMPL_COCOA' and guard GTK specific fields with
USE_GTK.

1 files changed, 563 insertions, 0 deletions

diff --git a/src/nsxwidget.m b/src/nsxwidget.m
new file mode 100644
index 00000000000..c5376dd311c
--- /dev/null
+++ b/src/nsxwidget.m
@@ -0,0 +1,563 @@
+/* NS Cocoa part implementation of xwidget and webkit widget.
+
+Copyright (C) 2019 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include "lisp.h"
+#include "blockinput.h"
+#include "dispextern.h"
+#include "buffer.h"
+#include "frame.h"
+#include "nsterm.h"
+#include "xwidget.h"
+
+#import <AppKit/AppKit.h>
+#import <WebKit/WebKit.h>
+
+/* Thoughts on NS Cocoa xwidget and webkit2:
+
+   Webkit2 process architecture seems to be very hostile for offscreen
+   rendering techniques, which is used by GTK xwiget implementation;
+   Specifically NSView level view sharing / copying is not working.
+
+   *** So only one view can be associcated with a model. ***
+
+   With this decision, implementation is plain and can expect best out
+   of webkit2's rationale.  But process and session structures will
+   diverge from GTK xwiget.  Though, cosmetically similar usages can
+   be presented and will be preferred, if agreeable.
+
+   For other widget types, OSR seems possible, but will not care for a
+   while.  */
+
+/* Xwidget webkit.  */
+
+@interface XwWebView : WKWebView
+<WKNavigationDelegate, WKUIDelegate, WKScriptMessageHandler>
+@property struct xwidget *xw;
+/* Map url to whether javascript is blocked by
+   'Content-Security-Policy' sandbox without allow-scripts.  */
+@property(retain) NSMutableDictionary *urlScriptBlocked;
+@end
+@implementation XwWebView : WKWebView
+
+- (id)initWithFrame:(CGRect)frame
+      configuration:(WKWebViewConfiguration *)configuration
+            xwidget:(struct xwidget *)xw
+{
+  /* Script controller to add script message handler and user script.  */
+  WKUserContentController *scriptor = [[WKUserContentController alloc] init];
+  configuration.userContentController = scriptor;
+
+  /* Enable inspect element context menu item for debugging.  */
+  [configuration.preferences setValue:@YES
+                               forKey:@"developerExtrasEnabled"];
+
+  Lisp_Object enablePlugins =
+    Fintern (build_string ("xwidget-webkit-enable-plugins"), Qnil);
+  if (!EQ (Fsymbol_value (enablePlugins), Qnil))
+    configuration.preferences.plugInsEnabled = YES;
+
+  self = [super initWithFrame:frame configuration:configuration];
+  if (self)
+    {
+      self.xw = xw;
+      self.urlScriptBlocked = [[NSMutableDictionary alloc] init];
+      self.navigationDelegate = self;
+      self.UIDelegate = self;
+      self.customUserAgent =
+        @"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6)"
+        @" AppleWebKit/603.3.8 (KHTML, like Gecko)"
+        @" Version/11.0.1 Safari/603.3.8";
+      [scriptor addScriptMessageHandler:self name:@"keyDown"];
+      [scriptor addUserScript:[[WKUserScript alloc]
+                                initWithSource:xwScript
+                                 injectionTime:
+                                  WKUserScriptInjectionTimeAtDocumentStart
+                                forMainFrameOnly:NO]];
+    }
+  return self;
+}
+
+- (void)webView:(WKWebView *)webView
+didFinishNavigation:(WKNavigation *)navigation
+{
+  if (EQ (Fbuffer_live_p (self.xw->buffer), Qt))
+    store_xwidget_event_string (self.xw, "load-changed", "");
+}
+
+- (void)webView:(WKWebView *)webView
+decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction
+decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler
+{
+  switch (navigationAction.navigationType) {
+  case WKNavigationTypeLinkActivated:
+    decisionHandler (WKNavigationActionPolicyAllow);
+    break;
+  default:
+    // decisionHandler (WKNavigationActionPolicyCancel);
+    decisionHandler (WKNavigationActionPolicyAllow);
+    break;
+  }
+}
+
+- (void)webView:(WKWebView *)webView
+decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse
+decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler
+{
+  decisionHandler (WKNavigationResponsePolicyAllow);
+
+  self.urlScriptBlocked[navigationResponse.response.URL] =
+    [NSNumber numberWithBool:NO];
+  if ([navigationResponse.response isKindOfClass:[NSHTTPURLResponse class]])
+    {
+      NSDictionary *headers =
+        ((NSHTTPURLResponse *) navigationResponse.response).allHeaderFields;
+      NSString *value = headers[@"Content-Security-Policy"];
+      if (value)
+        {
+          /* TODO: Sloppy parsing of 'Content-Security-Policy' value.  */
+          NSRange sandbox = [value rangeOfString:@"sandbox"];
+          if (sandbox.location != NSNotFound
+              && (sandbox.location == 0
+                  || [value characterAtIndex:(sandbox.location - 1)] == ' '
+                  || [value characterAtIndex:(sandbox.location - 1)] == ';'))
+            {
+              NSRange allowScripts = [value rangeOfString:@"allow-scripts"];
+              if (allowScripts.location == NSNotFound
+                  || allowScripts.location < sandbox.location)
+                self.urlScriptBlocked[navigationResponse.response.URL] =
+                  [NSNumber numberWithBool:YES];
+            }
+        }
+    }
+}
+
+/* No additional new webview or emacs window will be created
+   for <a ... target="_blank">.  */
+- (WKWebView *)webView:(WKWebView *)webView
+createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration
+   forNavigationAction:(WKNavigationAction *)navigationAction
+        windowFeatures:(WKWindowFeatures *)windowFeatures
+{
+  if (!navigationAction.targetFrame.isMainFrame)
+    [webView loadRequest:navigationAction.request];
+  return nil;
+}
+
+/* Open panel for file upload.  */
+- (void)webView:(WKWebView *)webView
+runOpenPanelWithParameters:(WKOpenPanelParameters *)parameters
+initiatedByFrame:(WKFrameInfo *)frame
+completionHandler:(void (^)(NSArray<NSURL *> *URLs))completionHandler
+{
+  NSOpenPanel *openPanel = [NSOpenPanel openPanel];
+  openPanel.canChooseFiles = YES;
+  openPanel.canChooseDirectories = NO;
+  openPanel.allowsMultipleSelection = parameters.allowsMultipleSelection;
+  if ([openPanel runModal] == NSModalResponseOK)
+    completionHandler (openPanel.URLs);
+  else
+    completionHandler (nil);
+}
+
+/* By forwarding mouse events to emacs view (frame)
+   - Mouse click in webview selects the window contains the webview.
+   - Correct mouse hand/arrow/I-beam is displayed (TODO: not perfect yet).
+*/
+
+- (void)mouseDown:(NSEvent *)event
+{
+  [self.xw->xv->emacswindow mouseDown:event];
+  [super mouseDown:event];
+}
+
+- (void)mouseUp:(NSEvent *)event
+{
+  [self.xw->xv->emacswindow mouseUp:event];
+  [super mouseUp:event];
+}
+
+/* Basically we want keyboard events handled by emacs unless an input
+   element has focus.  Especially, while incremental search, we set
+   emacs as first responder to avoid focus held in an input element
+   with matching text.  */
+
+- (void)keyDown:(NSEvent *)event
+{
+  Lisp_Object var = Fintern (build_string ("isearch-mode"), Qnil);
+  Lisp_Object val = buffer_local_value (var, Fcurrent_buffer ());
+  if (!EQ (val, Qunbound) && !EQ (val, Qnil))
+    {
+      [self.window makeFirstResponder:self.xw->xv->emacswindow];
+      [self.xw->xv->emacswindow keyDown:event];
+      return;
+    }
+
+  /* Emacs handles keyboard events when javascript is blocked.  */
+  if ([self.urlScriptBlocked[self.URL] boolValue])
+    {
+      [self.xw->xv->emacswindow keyDown:event];
+      return;
+    }
+
+  [self evaluateJavaScript:@"xwHasFocus()"
+         completionHandler:^(id result, NSError *error) {
+      if (error)
+        {
+          NSLog (@"xwHasFocus: %@", error);
+          [self.xw->xv->emacswindow keyDown:event];
+        }
+      else if (result)
+        {
+          NSNumber *hasFocus = result; /* __NSCFBoolean */
+          if (!hasFocus.boolValue)
+            [self.xw->xv->emacswindow keyDown:event];
+          else
+            [super keyDown:event];
+        }
+    }];
+}
+
+- (void)interpretKeyEvents:(NSArray<NSEvent *> *)eventArray
+{
+  /* We should do nothing and do not forward (default implementation
+     if we not override here) to let emacs collect key events and ask
+     interpretKeyEvents to its superclass.  */
+}
+
+static NSString *xwScript;
++ (void)initialize
+{
+  /* Find out if an input element has focus.
+     Message to script message handler when 'C-g' key down.  */
+  if (!xwScript)
+    xwScript =
+      @"function xwHasFocus() {"
+      @"  var ae = document.activeElement;"
+      @"  if (ae) {"
+      @"    var name = ae.nodeName;"
+      @"    return name == 'INPUT' || name == 'TEXTAREA';"
+      @"  } else {"
+      @"    return false;"
+      @"  }"
+      @"}"
+      @"function xwKeyDown(event) {"
+      @"  if (event.ctrlKey && event.key == 'g') {"
+      @"    window.webkit.messageHandlers.keyDown.postMessage('C-g');"
+      @"  }"
+      @"}"
+      @"document.addEventListener('keydown', xwKeyDown);"
+      ;
+}
+
+/* Confirming to WKScriptMessageHandler, listens concerning keyDown in
+   webkit. Currently 'C-g'.  */
+- (void)userContentController:(WKUserContentController *)userContentController
+      didReceiveScriptMessage:(WKScriptMessage *)message
+{
+  if ([message.body isEqualToString:@"C-g"])
+    {
+      /* Just give up focus, no relay "C-g" to emacs, another "C-g"
+         follows will be handled by emacs.  */
+      [self.window makeFirstResponder:self.xw->xv->emacswindow];
+    }
+}
+
+@end
+
+/* Xwidget webkit commands.  */
+
+static Lisp_Object build_string_with_nsstr (NSString *nsstr);
+
+bool
+nsxwidget_is_web_view (struct xwidget *xw)
+{
+  return xw->xwWidget != NULL &&
+    [xw->xwWidget isKindOfClass:WKWebView.class];
+}
+/* @Note ATS - Need application transport security in 'Info.plist' or
+   remote pages will not loaded.  */
+void
+nsxwidget_webkit_goto_uri (struct xwidget *xw, const char *uri)
+{
+  XwWebView *xwWebView = (XwWebView *) xw->xwWidget;
+  NSString *urlString = [NSString stringWithUTF8String:uri];
+  NSURL *url = [NSURL URLWithString:urlString];
+  NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];
+  [xwWebView loadRequest:urlRequest];
+}
+
+void
+nsxwidget_webkit_zoom (struct xwidget *xw, double zoom_change)
+{
+  XwWebView *xwWebView = (XwWebView *) xw->xwWidget;
+  xwWebView.magnification += zoom_change;
+  /* TODO: setMagnification:centeredAtPoint.  */
+}
+
+/* Build lisp string */
+static Lisp_Object
+build_string_with_nsstr (NSString *nsstr)
+{
+  const char *utfstr = [nsstr UTF8String];
+  NSUInteger bytes = [nsstr lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
+  return make_string (utfstr, bytes);
+}
+
+/* Recursively convert an objc native type JavaScript value to a Lisp
+   value.  Mostly copied from GTK xwidget 'webkit_js_to_lisp'.  */
+static Lisp_Object
+js_to_lisp (id value)
+{
+  if (value == nil || [value isKindOfClass:NSNull.class])
+    return Qnil;
+  else if ([value isKindOfClass:NSString.class])
+    return build_string_with_nsstr ((NSString *) value);
+  else if ([value isKindOfClass:NSNumber.class])
+    {
+      NSNumber *nsnum = (NSNumber *) value;
+      char type = nsnum.objCType[0];
+      if (type == 'c') /* __NSCFBoolean has type character 'c'.  */
+        return nsnum.boolValue? Qt : Qnil;
+      else
+        {
+          if (type == 'i' || type == 'l')
+            return make_int (nsnum.longValue);
+          else if (type == 'f' || type == 'd')
+            return make_float (nsnum.doubleValue);
+          /* else fall through.  */
+        }
+    }
+  else if ([value isKindOfClass:NSArray.class])
+    {
+      NSArray *nsarr = (NSArray *) value;
+      EMACS_INT n = nsarr.count;
+      Lisp_Object obj;
+      struct Lisp_Vector *p = allocate_vector (n);
+
+      for (ptrdiff_t i = 0; i < n; ++i)
+        p->contents[i] = js_to_lisp ([nsarr objectAtIndex:i]);
+      XSETVECTOR (obj, p);
+      return obj;
+    }
+  else if ([value isKindOfClass:NSDictionary.class])
+    {
+      NSDictionary *nsdict = (NSDictionary *) value;
+      NSArray *keys = nsdict.allKeys;
+      ptrdiff_t n = keys.count;
+      Lisp_Object obj;
+      struct Lisp_Vector *p = allocate_vector (n);
+
+      for (ptrdiff_t i = 0; i < n; ++i)
+        {
+          NSString *prop_key = (NSString *) [keys objectAtIndex:i];
+          id prop_value = [nsdict valueForKey:prop_key];
+          p->contents[i] = Fcons (build_string_with_nsstr (prop_key),
+                                  js_to_lisp (prop_value));
+        }
+      XSETVECTOR (obj, p);
+      return obj;
+    }
+  NSLog (@"Unhandled type in javascript result");
+  return Qnil;
+}
+
+void
+nsxwidget_webkit_execute_script (struct xwidget *xw, const char *script,
+                                 Lisp_Object fun)
+{
+  XwWebView *xwWebView = (XwWebView *) xw->xwWidget;
+  if ([xwWebView.urlScriptBlocked[xwWebView.URL] boolValue])
+    {
+      message ("Javascript is blocked by 'CSP: sandbox'.");
+      return;
+    }
+
+  NSString *javascriptString = [NSString stringWithUTF8String:script];
+  [xwWebView evaluateJavaScript:javascriptString
+              completionHandler:^(id result, NSError *error) {
+      if (error)
+        {
+          NSLog (@"evaluateJavaScript error : %@", error.localizedDescription);
+          NSLog (@"error script=%@", javascriptString);
+        }
+      else if (result && FUNCTIONP (fun))
+        {
+          // NSLog (@"result=%@, type=%@", result, [result class]);
+          Lisp_Object lisp_value = js_to_lisp (result);
+          store_xwidget_js_callback_event (xw, fun, lisp_value);
+        }
+    }];
+}
+
+/* Window containing an xwidget.  */
+
+@implementation XwWindow
+- (BOOL)isFlipped { return YES; }
+@end
+
+/* Xwidget model, macOS Cocoa part.  */
+
+void
+nsxwidget_init(struct xwidget *xw)
+{
+  block_input ();
+  NSRect rect = NSMakeRect (0, 0, xw->width, xw->height);
+  xw->xwWidget = [[XwWebView alloc]
+                   initWithFrame:rect
+                   configuration:[[WKWebViewConfiguration alloc] init]
+                         xwidget:xw];
+  xw->xwWindow = [[XwWindow alloc]
+                   initWithFrame:rect];
+  [xw->xwWindow addSubview:xw->xwWidget];
+  xw->xv = NULL; /* for 1 to 1 relationship of webkit2.  */
+  unblock_input ();
+}
+
+void
+nsxwidget_kill (struct xwidget *xw)
+{
+  if (xw)
+    {
+      WKUserContentController *scriptor =
+        ((XwWebView *) xw->xwWidget).configuration.userContentController;
+      [scriptor removeAllUserScripts];
+      [scriptor removeScriptMessageHandlerForName:@"keyDown"];
+      [scriptor release];
+      if (xw->xv)
+        xw->xv->model = Qnil; /* Make sure related view stale.  */
+
+      /* This stops playing audio when a xwidget-webkit buffer is
+         killed.  I could not find other solution.  */
+      nsxwidget_webkit_goto_uri (xw, "about:blank");
+
+      [((XwWebView *) xw->xwWidget).urlScriptBlocked release];
+      [xw->xwWidget removeFromSuperviewWithoutNeedingDisplay];
+      [xw->xwWidget release];
+      [xw->xwWindow removeFromSuperviewWithoutNeedingDisplay];
+      [xw->xwWindow release];
+      xw->xwWidget = nil;
+    }
+}
+
+void
+nsxwidget_resize (struct xwidget *xw)
+{
+  if (xw->xwWidget)
+    {
+      [xw->xwWindow setFrameSize:NSMakeSize(xw->width, xw->height)];
+      [xw->xwWidget setFrameSize:NSMakeSize(xw->width, xw->height)];
+    }
+}
+
+Lisp_Object
+nsxwidget_get_size (struct xwidget *xw)
+{
+  return list2i (xw->xwWidget.frame.size.width,
+                 xw->xwWidget.frame.size.height);
+}
+
+/* Xwidget view, macOS Cocoa part.  */
+
+@implementation XvWindow : NSView
+- (BOOL)isFlipped { return YES; }
+@end
+
+void
+nsxwidget_init_view (struct xwidget_view *xv,
+                     struct xwidget *xw,
+                     struct glyph_string *s,
+                     int x, int y)
+{
+  /* 'x_draw_xwidget_glyph_string' will calculate correct position and
+     size of clip to draw in emacs buffer window.  Thus, just begin at
+     origin with no crop.  */
+  xv->x = x;
+  xv->y = y;
+  xv->clip_left = 0;
+  xv->clip_right = xw->width;
+  xv->clip_top = 0;
+  xv->clip_bottom = xw->height;
+
+  xv->xvWindow = [[XvWindow alloc]
+                   initWithFrame:NSMakeRect (x, y, xw->width, xw->height)];
+  xv->xvWindow.xw = xw;
+  xv->xvWindow.xv = xv;
+
+  xw->xv = xv; /* For 1 to 1 relationship of webkit2.  */
+  [xv->xvWindow addSubview:xw->xwWindow];
+
+  xv->emacswindow = FRAME_NS_VIEW (s->f);
+  [xv->emacswindow addSubview:xv->xvWindow];
+}
+
+void
+nsxwidget_delete_view (struct xwidget_view *xv)
+{
+  if (!EQ (xv->model, Qnil))
+    {
+      struct xwidget *xw = XXWIDGET (xv->model);
+      [xw->xwWindow removeFromSuperviewWithoutNeedingDisplay];
+      xw->xv = NULL; /* Now model has no view.  */
+    }
+  [xv->xvWindow removeFromSuperviewWithoutNeedingDisplay];
+  [xv->xvWindow release];
+}
+
+void
+nsxwidget_show_view (struct xwidget_view *xv)
+{
+  xv->hidden = NO;
+  [xv->xvWindow setFrameOrigin:NSMakePoint(xv->x + xv->clip_left,
+                                           xv->y + xv->clip_top)];
+}
+
+void
+nsxwidget_hide_view (struct xwidget_view *xv)
+{
+  xv->hidden = YES;
+  [xv->xvWindow setFrameOrigin:NSMakePoint(10000, 10000)];
+}
+
+void
+nsxwidget_resize_view (struct xwidget_view *xv, int width, int height)
+{
+  [xv->xvWindow setFrameSize:NSMakeSize(width, height)];
+}
+
+void
+nsxwidget_move_view (struct xwidget_view *xv, int x, int y)
+{
+  [xv->xvWindow setFrameOrigin:NSMakePoint (x, y)];
+}
+
+/* Move model window in container (view window).  */
+void
+nsxwidget_move_widget_in_view (struct xwidget_view *xv, int x, int y)
+{
+  struct xwidget *xww = xv->xvWindow.xw;
+  [xww->xwWindow setFrameOrigin:NSMakePoint (x, y)];
+}
+
+void
+nsxwidget_set_needsdisplay (struct xwidget_view *xv)
+{
+  xv->xvWindow.needsDisplay = YES;
+}