Avoid an infinite loop when searching for a single diacritic

test/unit/pdf_find_controller_spec.js

@@ -13,11 +13,11 @@
  * limitations under the License.
  */
 
+import { FindState, PDFFindController } from "../../web/pdf_find_controller.js";
 import { buildGetDocumentParams } from "./test_utils.js";
 import { EventBus } from "../../web/event_utils.js";
 import { getDocument } from "../../src/display/api.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
-import { PDFFindController } from "../../web/pdf_find_controller.js";
 import { SimpleLinkService } from "../../web/pdf_link_service.js";
 
 const tracemonkeyFileName = "tracemonkey.pdf";
@@ -156,6 +156,38 @@ function testSearch({
   });
 }
 
+function testEmptySearch({ eventBus, pdfFindController, state }) {
+  return new Promise(function (resolve) {
+    const eventState = Object.assign(
+      Object.create(null),
+      {
+        source: this,
+        type: "",
+        query: null,
+        caseSensitive: false,
+        entireWord: false,
+        phraseSearch: true,
+        findPrevious: false,
+        matchDiacritics: false,
+      },
+      state
+    );
+    eventBus.dispatch("find", eventState);
+
+    eventBus.on(
+      "updatefindcontrolstate",
+      function onUpdatefindcontrolstate(evt) {
+        if (evt.state !== FindState.NOT_FOUND) {
+          return;
+        }
+        eventBus.off("updatefindcontrolstate", onUpdatefindcontrolstate);
+        expect(evt.matchesCount.total).toBe(0);
+        resolve();
+      }
+    );
+  });
+}
+
 describe("pdf_find_controller", function () {
   it("performs a normal search", async function () {
     const { eventBus, pdfFindController } = await initPdfFindController();
@@ -689,4 +721,16 @@ describe("pdf_find_controller", function () {
       pageMatchesLength: [[5]],
     });
   });
+
+  it("performs a search with a single diacritic", async function () {
+    const { eventBus, pdfFindController } = await initPdfFindController();
+
+    await testEmptySearch({
+      eventBus,
+      pdfFindController,
+      state: {
+        query: "\u064E",
+      },
+    });
+  });
 });

web/pdf_find_controller.js

@@ -591,9 +591,13 @@ class PDFFindController {
   }
 
   #calculateRegExpMatch(query, entireWord, pageIndex, pageContent) {
-    const matches = [],
-      matchesLength = [];
-
+    const matches = (this._pageMatches[pageIndex] = []);
+    const matchesLength = (this._pageMatchesLength[pageIndex] = []);
+    if (!query) {
+      // The query can be empty because some chars like diacritics could have
+      // been stripped out.
+      return;
+    }
     const diffs = this._pageDiffs[pageIndex];
     let match;
     while ((match = query.exec(pageContent)) !== null) {
@@ -615,8 +619,6 @@ class PDFFindController {
         matchesLength.push(matchLen);
       }
     }
-    this._pageMatches[pageIndex] = matches;
-    this._pageMatchesLength[pageIndex] = matchesLength;
   }
 
   #convertToRegExpString(query, hasDiacritics) {
@@ -691,7 +693,7 @@ class PDFFindController {
 
   #calculateMatch(pageIndex) {
     let query = this.#query;
-    if (query.length === 0) {
+    if (!query) {
       // Do nothing: the matches should be wiped out already.
       return;
     }
@@ -724,7 +726,7 @@ class PDFFindController {
     }
 
     const flags = `g${isUnicode ? "u" : ""}${caseSensitive ? "" : "i"}`;
-    query = new RegExp(query, flags);
+    query = query ? new RegExp(query, flags) : null;
 
     this.#calculateRegExpMatch(query, entireWord, pageIndex, pageContent);
 
@@ -854,7 +856,7 @@ class PDFFindController {
     }
 
     // If there's no query there's no point in searching.
-    if (this.#query === "") {
+    if (!this.#query) {
       this.#updateUIState(FindState.FOUND);
       return;
     }