add CancellationToken, but not wired up yet

cli/js/40_lint.js

@@ -13,6 +13,7 @@ const {
   op_lint_get_source,
   op_lint_report,
   op_lint_create_serialized_ast,
+  op_is_cancelled,
 } = core.ops;
 
 // Keep in sync with Rust
@@ -61,6 +62,16 @@ const state = {
   installedPlugins: new Set(),
 };
 
+/**
+ * This implementation calls into Rust to check if Tokio's cancellation token
+ * has already been canceled.
+ */
+class CancellationToken {
+  isCancellationRequested() {
+    return op_is_cancelled();
+  }
+}
+
 /**
  * Every rule gets their own instance of this class. This is the main
  * API lint rules interact with.
@@ -893,10 +904,11 @@ export function runPluginsForFile(fileName, serializedAst) {
     visitors.push({ info, matcher });
   }
 
+  const token = new CancellationToken();
   // Traverse ast with all visitors at the same time to avoid traversing
   // multiple times.
   try {
-    traverse(ctx, visitors, ctx.rootOffset);
+    traverse(ctx, visitors, ctx.rootOffset, token);
   } finally {
     ctx.nodes.clear();
 
@@ -911,10 +923,12 @@ export function runPluginsForFile(fileName, serializedAst) {
  * @param {AstContext} ctx
  * @param {CompiledVisitor[]} visitors
  * @param {number} offset
+ * @param {CancellationToken} cancellationToken
  */
-function traverse(ctx, visitors, offset) {
+function traverse(ctx, visitors, offset, cancellationToken) {
   // The 0 offset is used to denote an empty/placeholder node
   if (offset === 0) return;
+  if (cancellationToken.isCancellationRequested()) return;
 
   const originalOffset = offset;
 
@@ -925,8 +939,8 @@ function traverse(ctx, visitors, offset) {
 
   for (let i = 0; i < visitors.length; i++) {
     const v = visitors[i];
-
     if (v.matcher(ctx.matcher, offset)) {
+      if (cancellationToken.isCancellationRequested()) return;
       if (v.info.exit !== NOOP) {
         if (exits === null) {
           exits = [v.info.exit];
@@ -952,13 +966,14 @@ function traverse(ctx, visitors, offset) {
     offset += 1;
 
     for (let i = 0; i < propCount; i++) {
+      if (cancellationToken.isCancellationRequested()) return;
       const kind = buf[offset + 1];
       offset += 2; // propId + propFlags
 
       if (kind === PropFlags.Ref) {
         const next = readU32(buf, offset);
         offset += 4;
-        traverse(ctx, visitors, next);
+        traverse(ctx, visitors, next, cancellationToken);
       } else if (kind === PropFlags.RefArr) {
         const len = readU32(buf, offset);
         offset += 4;
@@ -966,7 +981,7 @@ function traverse(ctx, visitors, offset) {
         for (let j = 0; j < len; j++) {
           const child = readU32(buf, offset);
           offset += 4;
-          traverse(ctx, visitors, child);
+          traverse(ctx, visitors, child, cancellationToken);
         }
       } else if (kind === PropFlags.String) {
         offset += 4;

cli/ops/lint.rs

@@ -12,6 +12,7 @@ use deno_core::OpState;
 use deno_lint::diagnostic::LintDiagnostic;
 use deno_lint::diagnostic::LintDiagnosticDetails;
 use deno_lint::diagnostic::LintDiagnosticRange;
+use tokio_util::sync::CancellationToken;
 
 use crate::tools::lint;
 use crate::tools::lint::PluginLogger;
@@ -21,7 +22,8 @@ deno_core::extension!(
   ops = [
     op_lint_create_serialized_ast,
     op_lint_report,
-    op_lint_get_source
+    op_lint_get_source,
+    op_is_cancelled
   ],
   options = {
     logger: PluginLogger,
@@ -40,6 +42,7 @@ deno_core::extension!(
 pub struct LintPluginContainer {
   pub diagnostics: Vec<LintDiagnostic>,
   pub source_text_info: Option<SourceTextInfo>,
+  token: CancellationToken,
 }
 
 impl LintPluginContainer {
@@ -88,6 +91,12 @@ pub fn op_print(state: &mut OpState, #[string] msg: &str, is_err: bool) {
   }
 }
 
+#[op2(fast)]
+fn op_is_cancelled(state: &mut OpState) -> bool {
+  let container = state.borrow_mut::<LintPluginContainer>();
+  container.token.is_cancelled()
+}
+
 #[op2]
 #[buffer]
 fn op_lint_create_serialized_ast(

runtime/js/99_main.js

@@ -533,6 +533,7 @@ const NOT_IMPORTED_OPS = [
   "op_lint_report",
   "op_lint_get_source",
   "op_lint_create_serialized_ast",
+  "op_is_cancelled",
 
   // Related to `Deno.test()` API
   "op_test_event_step_result_failed",