feat: parse SharedArrayBuffer and validate AllowShared (#747)

* feat: parse SharedArrayBuffer and validate AllowShared

* Update README.md

* more test

* Update type.js

Author: saschanaz

.gitattributes

@@ -1,3 +1,2 @@
 # Auto detect text files and perform LF normalization
-* text=auto
-/test/*/** text eol=lf
+* text=auto eol=lf

README.md

@@ -199,6 +199,7 @@ properties:
    * `no-constructible-global`: Interfaces with `[Global]` cannot have constructors.
    * `renamed-legacy`: Legacy extended attributes must use their new names.
    * `replace-void`: `void` type is replaced by `undefined` type.
+   * `migrate-allowshared`: `[AllowShared] BufferSource` is replaced by `AllowSharedBufferSource`.
 * `input`: a short peek at the text at the point where the error happened
 * `tokens`: the five tokens at the point of error, as understood by the tokeniser
   (this is the same content as `input`, but seen from the tokeniser's point of view)

lib/productions/type.js

@@ -194,6 +194,26 @@ export class Type extends Base {
   *validate(defs) {
     yield* this.extAttrs.validate(defs);
 
+    if (this.idlType === "BufferSource") {
+      // XXX: For now this is a hack. Consider moving parents' extAttrs into types as the spec says:
+      // https://webidl.spec.whatwg.org/#idl-annotated-types
+      for (const extAttrs of [this.extAttrs, this.parent?.extAttrs]) {
+        for (const extAttr of extAttrs) {
+          if (extAttr.name !== "AllowShared") {
+            continue;
+          }
+          const message = `\`[AllowShared] BufferSource\` is now replaced with AllowSharedBufferSource.`;
+          yield validationError(
+            this.tokens.base,
+            this,
+            "migrate-allowshared",
+            message,
+            { autofix: replaceAllowShared(this, extAttr, extAttrs) }
+          );
+        }
+      }
+    }
+
     if (this.idlType === "void") {
       const message = `\`void\` is now replaced by \`undefined\`. Refer to the \
 [relevant GitHub issue](https://github.com/whatwg/webidl/issues/60) \
@@ -273,6 +293,23 @@ for more information.`;
   }
 }
 
+/**
+ * @param {Type} type
+ * @param {import("./extended-attributes.js").SimpleExtendedAttribute} extAttr
+ * @param {ExtendedAttributes} extAttrs
+ */
+function replaceAllowShared(type, extAttr, extAttrs) {
+  return () => {
+    const index = extAttrs.indexOf(extAttr);
+    extAttrs.splice(index, 1);
+    if (!extAttrs.length && type.tokens.base.trivia.match(/^\s$/)) {
+      type.tokens.base.trivia = ""; // (let's not remove comments)
+    }
+
+    type.tokens.base.value = "AllowSharedBufferSource";
+  };
+}
+
 /**
  * @param {Type} type
  */

lib/tokeniser.js

@@ -18,6 +18,7 @@ const tokenRe = {
 
 export const typeNameKeywords = [
   "ArrayBuffer",
+  "SharedArrayBuffer",
   "DataView",
   "Int8Array",
   "Int16Array",

test/autofix.js

@@ -342,4 +342,22 @@ describe("Writer template functions", () => {
     `;
     expect(autofix(input)).toBe(output);
   });
+
+  it("should replace [AllowShared] BufferSource into undefined", () => {
+    const input = `
+      [Exposed=Window]
+      interface Foo {
+        undefined foo([AllowShared] /* Accept SharedArrayBuffer */ BufferSource source);
+        undefined foo(optional [AllowShared] /* Accept SharedArrayBuffer */ BufferSource source);
+      };
+    `;
+    const output = `
+      [Exposed=Window]
+      interface Foo {
+        undefined foo( /* Accept SharedArrayBuffer */ AllowSharedBufferSource source);
+        undefined foo(optional /* Accept SharedArrayBuffer */ AllowSharedBufferSource source);
+      };
+    `;
+    expect(autofix(input)).toBe(output);
+  });
 });

test/invalid/baseline/invalid-allowshared.txt

@@ -0,0 +1,3 @@
+(migrate-allowshared) Validation error at line 3 in invalid-allowshared.webidl:
+ foo([AllowShared] BufferSource source);
+                   ^ `[AllowShared] BufferSource` is now replaced with AllowSharedBufferSource.

test/invalid/baseline/sharedarraybuffer.txt

@@ -0,0 +1,3 @@
+Syntax error at line 1 in sharedarraybuffer.webidl:
+interface SharedArrayBuffer {};
+          ^ Missing name in interface

test/invalid/idl/invalid-allowshared.webidl

@@ -0,0 +1,4 @@
+[Exposed=Window]
+interface Foo {
+    undefined foo([AllowShared] BufferSource source);
+};

test/invalid/idl/sharedarraybuffer.webidl

@@ -0,0 +1 @@
+interface SharedArrayBuffer {};

test/syntax/baseline/sharedarraybuffer.json

@@ -0,0 +1,89 @@
+[
+    {
+        "type": "interface",
+        "name": "Foo",
+        "inheritance": null,
+        "members": [
+            {
+                "type": "operation",
+                "name": "foo",
+                "idlType": {
+                    "type": "return-type",
+                    "extAttrs": [],
+                    "generic": "",
+                    "nullable": false,
+                    "union": false,
+                    "idlType": "undefined"
+                },
+                "arguments": [
+                    {
+                        "type": "argument",
+                        "name": "buffer",
+                        "extAttrs": [],
+                        "idlType": {
+                            "type": "argument-type",
+                            "extAttrs": [],
+                            "generic": "",
+                            "nullable": false,
+                            "union": false,
+                            "idlType": "SharedArrayBuffer"
+                        },
+                        "default": null,
+                        "optional": false,
+                        "variadic": false
+                    }
+                ],
+                "extAttrs": [],
+                "special": ""
+            },
+            {
+                "type": "operation",
+                "name": "foo",
+                "idlType": {
+                    "type": "return-type",
+                    "extAttrs": [],
+                    "generic": "",
+                    "nullable": false,
+                    "union": false,
+                    "idlType": "undefined"
+                },
+                "arguments": [
+                    {
+                        "type": "argument",
+                        "name": "source",
+                        "extAttrs": [],
+                        "idlType": {
+                            "type": "argument-type",
+                            "extAttrs": [],
+                            "generic": "",
+                            "nullable": false,
+                            "union": false,
+                            "idlType": "AllowSharedBufferSource"
+                        },
+                        "default": null,
+                        "optional": false,
+                        "variadic": false
+                    }
+                ],
+                "extAttrs": [],
+                "special": ""
+            }
+        ],
+        "extAttrs": [
+            {
+                "type": "extended-attribute",
+                "name": "Exposed",
+                "rhs": {
+                    "type": "identifier",
+                    "value": "Window"
+                },
+                "arguments": []
+            }
+        ],
+        "partial": false
+    },
+    {
+        "type": "eof",
+        "value": ""
+    }
+]