1 files changed, 96 insertions, 0 deletions
diff --git a/devtools/client/debugger/src/actions/ast/setInScopeLines.js b/devtools/client/debugger/src/actions/ast/setInScopeLines.js
new file mode 100644
index 0000000000..a55ff88bbb
--- /dev/null
+++ b/devtools/client/debugger/src/actions/ast/setInScopeLines.js
@@ -0,0 +1,96 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import {
+  hasInScopeLines,
+  getLocationSource,
+  getSourceTextContent,
+  getVisibleSelectedFrame,
+} from "../../selectors";
+
+import { getSourceLineCount } from "../../utils/source";
+
+import { isFulfilled } from "../../utils/async-value";
+
+function getOutOfScopeLines(outOfScopeLocations) {
+  if (!outOfScopeLocations) {
+    return null;
+  }
+
+  const uniqueLines = new Set();
+  for (const location of outOfScopeLocations) {
+    for (let i = location.start.line; i < location.end.line; i++) {
+      uniqueLines.add(i);
+    }
+  }
+
+  return uniqueLines;
+}
+
+async function getInScopeLines(
+  cx,
+  location,
+  { dispatch, getState, parserWorker }
+) {
+  const source = getLocationSource(getState(), location);
+  const sourceTextContent = getSourceTextContent(getState(), location);
+
+  let locations = null;
+  if (location.line && source && !source.isWasm) {
+    locations = await parserWorker.findOutOfScopeLocations(source.id, location);
+  }
+
+  const linesOutOfScope = getOutOfScopeLines(locations);
+  const sourceNumLines =
+    !sourceTextContent || !isFulfilled(sourceTextContent)
+      ? 0
+      : getSourceLineCount(sourceTextContent.value);
+
+  const noLinesOutOfScope =
+    linesOutOfScope == null || linesOutOfScope.size == 0;
+
+  // This operation can be very costly for large files so we sacrifice a bit of readability
+  // for performance sake.
+  // We initialize an array with a fixed size and we'll directly assign value for lines
+  // that are not out of scope. This is much faster than having an empty array and pushing
+  // into it.
+  const sourceLines = new Array(sourceNumLines);
+  for (let i = 0; i < sourceNumLines; i++) {
+    const line = i + 1;
+    if (noLinesOutOfScope || !linesOutOfScope.has(line)) {
+      sourceLines[i] = line;
+    }
+  }
+
+  // Finally we need to remove any undefined values, i.e. the ones that were matching
+  // out of scope lines.
+  return sourceLines.filter(i => i != undefined);
+}
+
+export function setInScopeLines(cx) {
+  return async thunkArgs => {
+    const { getState, dispatch } = thunkArgs;
+    const visibleFrame = getVisibleSelectedFrame(getState());
+
+    if (!visibleFrame) {
+      return;
+    }
+
+    const { location } = visibleFrame;
+    const sourceTextContent = getSourceTextContent(getState(), location);
+
+    if (hasInScopeLines(getState(), location) || !sourceTextContent) {
+      return;
+    }
+
+    const lines = await getInScopeLines(cx, location, thunkArgs);
+
+    dispatch({
+      type: "IN_SCOPE_LINES",
+      cx,
+      location,
+      lines,
+    });
+  };
+}