Bug 1858788 - Implement ClipboardItem.supports; r=nika

See https://w3c.github.io/clipboard-apis/#dom-clipboarditem-supports and we
currently support mandatory types only.

Differential Revision: https://phabricator.services.mozilla.com/D205651

dom/events/Clipboard.cpp

@@ -59,6 +59,19 @@ bool Clipboard::IsTestingPrefEnabledOrHasReadPermission(
                                                 nsGkAtoms::clipboardRead);
 }
 
+// Mandatory data types defined in
+// https://w3c.github.io/clipboard-apis/#mandatory-data-types-x. The types
+// should be in the same order as kNonPlainTextExternalFormats in
+// DataTransfer.
+static const nsLiteralCString kMandatoryDataTypes[] = {
+    nsLiteralCString(kHTMLMime), nsLiteralCString(kTextMime),
+    nsLiteralCString(kPNGImageMime)};
+
+// static
+Span<const nsLiteralCString> Clipboard::MandatoryDataTypes() {
+  return Span<const nsLiteralCString>(kMandatoryDataTypes);
+}
+
 namespace {
 
 /**
@@ -87,16 +100,6 @@ class ClipboardGetCallback : public nsIAsyncClipboardGetCallback {
   RefPtr<Promise> mPromise;
 };
 
-static nsTArray<nsCString> MandatoryDataTypesAsCStrings() {
-  // Mandatory data types defined in
-  // https://w3c.github.io/clipboard-apis/#mandatory-data-types-x. The types
-  // should be in the same order as kNonPlainTextExternalFormats in
-  // DataTransfer.
-  return nsTArray<nsCString>{nsLiteralCString(kHTMLMime),
-                             nsLiteralCString(kTextMime),
-                             nsLiteralCString(kPNGImageMime)};
-}
-
 class ClipboardGetCallbackForRead final : public ClipboardGetCallback {
  public:
   explicit ClipboardGetCallbackForRead(nsIGlobalObject* aGlobal,
@@ -122,7 +125,7 @@ class ClipboardGetCallbackForRead final : public ClipboardGetCallback {
     AutoTArray<RefPtr<ClipboardItem::ItemEntry>, 3> entries;
     // We might reuse the request from DataTransfer created for paste event,
     // which could contain more types that are not in the mandatory list.
-    for (const auto& format : MandatoryDataTypesAsCStrings()) {
+    for (const auto& format : kMandatoryDataTypes) {
       if (flavorList.Contains(format)) {
         auto entry = MakeRefPtr<ClipboardItem::ItemEntry>(
             mGlobal, NS_ConvertUTF8toUTF16(format));
@@ -287,10 +290,13 @@ void Clipboard::RequestRead(Promise* aPromise, ReadRequestType aType,
         return;
       }
 
+      AutoTArray<nsCString, ArrayLength(kMandatoryDataTypes)> types;
+      types.AppendElements(Span<const nsLiteralCString>(kMandatoryDataTypes));
+
       callback = MakeRefPtr<ClipboardGetCallbackForRead>(global, std::move(p));
-      rv = clipboardService->AsyncGetData(
-          MandatoryDataTypesAsCStrings(), nsIClipboard::kGlobalClipboard,
-          owner->GetWindowContext(), &aPrincipal, callback);
+      rv = clipboardService->AsyncGetData(types, nsIClipboard::kGlobalClipboard,
+                                          owner->GetWindowContext(),
+                                          &aPrincipal, callback);
       break;
     }
     case ReadRequestType::eReadText: {

dom/events/Clipboard.h

@@ -51,6 +51,8 @@ class Clipboard : public DOMEventTargetHelper {
   // testing purposes.
   static bool ReadTextEnabled(JSContext* aCx, JSObject* aGlobal);
 
+  static Span<const nsLiteralCString> MandatoryDataTypes();
+
   virtual JSObject* WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto) override;
 

dom/events/ClipboardItem.cpp

@@ -6,6 +6,7 @@
 
 #include "mozilla/dom/ClipboardItem.h"
 
+#include "mozilla/dom/Clipboard.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/Record.h"
 #include "nsComponentManagerUtils.h"
@@ -290,6 +291,17 @@ already_AddRefed<ClipboardItem> ClipboardItem::Constructor(
   return item.forget();
 }
 
+// static
+bool ClipboardItem::Supports(const GlobalObject& aGlobal,
+                             const nsAString& aType) {
+  for (const auto& mandatoryType : Clipboard::MandatoryDataTypes()) {
+    if (CompareUTF8toUTF16(mandatoryType, aType) == 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
 void ClipboardItem::GetTypes(nsTArray<nsString>& aTypes) const {
   for (const auto& item : mItems) {
     aTypes.AppendElement(item->Type());

dom/events/ClipboardItem.h

@@ -107,6 +107,8 @@ class ClipboardItem final : public nsWrapperCache {
       const Record<nsString, OwningNonNull<Promise>>& aItems,
       const ClipboardItemOptions& aOptions, ErrorResult& aRv);
 
+  static bool Supports(const GlobalObject& aGlobal, const nsAString& aType);
+
   dom::PresentationStyle PresentationStyle() const {
     return mPresentationStyle;
   };

dom/webidl/Clipboard.webidl

@@ -53,6 +53,8 @@ interface ClipboardItem {
 
   [NewObject]
   Promise<Blob> getType(DOMString type);
+
+  static boolean supports(DOMString type);
 };
 
 enum PresentationStyle { "unspecified", "inline", "attachment" };

testing/web-platform/meta/clipboard-apis/clipboard-item.https.html.ini

@@ -1,5 +1,11 @@
 [clipboard-item.https.html]
   expected:
     if (os == "android") and fission: [OK, TIMEOUT]
-  [supports(DOMString) returns true for types that are supported, false otherwise]
+  [supports(image/svg+xml) returns true]
+    expected: FAIL
+
+  [supports(web foo/bar) returns true]
+    expected: FAIL
+
+  [supports(web text/html) returns true]
     expected: FAIL

testing/web-platform/meta/clipboard-apis/idlharness.https.window.js.ini

@@ -1,5 +1,3 @@
 [idlharness.https.window.html]
   expected:
     if (os == "android") and fission: [OK, TIMEOUT]
-  [ClipboardItem interface: operation supports(DOMString)]
-    expected: FAIL

testing/web-platform/tests/clipboard-apis/clipboard-item.https.html

@@ -96,21 +96,28 @@ promise_test(async () => {
   assert_equals(text, 'xxx');
 }, "getType(DOMString invalid type) converts DOMString to Blob");
 
-promise_test(async () => {
-  assert_true(ClipboardItem.supports('text/plain'));
-  assert_true(ClipboardItem.supports('text/html'));
-  assert_true(ClipboardItem.supports('image/png'));
-  assert_true(ClipboardItem.supports('image/svg+xml'));
-  assert_false(ClipboardItem.supports('web '));
-  assert_false(ClipboardItem.supports('web')); // without space.
-  assert_false(ClipboardItem.supports('web foo'));
-  assert_false(ClipboardItem.supports('foo/bar'));
-  assert_true(ClipboardItem.supports('web foo/bar'));
-  assert_true(ClipboardItem.supports('web text/html'));
-  assert_false(ClipboardItem.supports('weB text/html'));
-  assert_false(ClipboardItem.supports(' web text/html'));
-  assert_false(ClipboardItem.supports('not a/real type'));
-  assert_false(ClipboardItem.supports(''));
-  assert_false(ClipboardItem.supports(' '));
-}, "supports(DOMString) returns true for types that are supported, false otherwise");
+[
+  // mandatory data types
+  ['text/plain', true],
+  ['text/html',  true],
+  ['image/png',  true],
+  // optional data types
+  ['image/svg+xml', true],
+  ['web foo/bar',   true],
+  ['web text/html', true],
+  // invalid types
+  ['web ',            false],
+  ['web',             false],
+  ['web foo',         false],
+  ['foo/bar',         false],
+  ['weB text/html',   false],
+  [' web text/html',  false],
+  ['not a/real type', false],
+  ['',                false],
+  [' ',               false],
+].forEach(([type, result]) => {
+  promise_test(async () => {
+    assert_equals(ClipboardItem.supports(type), result);
+  }, `supports(${type}) returns ${result ? "true" : "false"}`);
+});
 </script>