From 236871c68b1330be9a62ae1534f7a53d9efe2f0e Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Mon, 1 Oct 2018 17:41:57 +0200
Subject: [PATCH] [Regression] Restore the ability to start searching before a
 document has loaded, and ignore searches for previously opened documents (PR
 10099 follow-up)

For many years it's been possible to enter a search term into the findbar(s) before the document has finised loading, such that searching starts immediately once it has loaded.
PR 10099 accidentally broke that, which I unfortunately missed during reviewing.

Since searching is asynchronous you cannot directly check in `executeCommand` if the document is loaded/current, but need to wait until searching is actually enabled first.

Furthermore this patch also ensures that the `_findTimeout` is always correctly cleared given that it adds further asynchronous behaviour to searching, since you obviously only want to deal with searches relevant to the current document.
---
 web/pdf_find_controller.js | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/web/pdf_find_controller.js b/web/pdf_find_controller.js
index cbd50dbb4..c103da0ba 100644
--- a/web/pdf_find_controller.js
+++ b/web/pdf_find_controller.js
@@ -110,9 +110,7 @@ class PDFFindController {
   }
 
   executeCommand(cmd, state) {
-    if (!this._pdfDocument) {
-      return;
-    }
+    const pdfDocument = this._pdfDocument;
 
     if (this._state === null || cmd !== 'findagain') {
       this._dirtyMatch = true;
@@ -121,14 +119,25 @@ class PDFFindController {
     this._updateUIState(FindState.PENDING);
 
     this._firstPagePromise.then(() => {
+      if (!this._pdfDocument ||
+          (pdfDocument && this._pdfDocument !== pdfDocument)) {
+        // If the document was closed before searching began, or if the search
+        // operation was relevant for a previously opened document, do nothing.
+        return;
+      }
       this._extractText();
 
-      clearTimeout(this._findTimeout);
+      if (this._findTimeout) {
+        clearTimeout(this._findTimeout);
+        this._findTimeout = null;
+      }
       if (cmd === 'find') {
         // Trigger the find action with a small delay to avoid starting the
         // search when the user is still typing (saving resources).
-        this._findTimeout =
-          setTimeout(this._nextMatch.bind(this), FIND_TIMEOUT);
+        this._findTimeout = setTimeout(() => {
+          this._nextMatch();
+          this._findTimeout = null;
+        }, FIND_TIMEOUT);
       } else {
         this._nextMatch();
       }
@@ -156,14 +165,19 @@ class PDFFindController {
     this._pendingFindMatches = Object.create(null);
     this._resumePageIdx = null;
     this._dirtyMatch = false;
+    clearTimeout(this._findTimeout);
     this._findTimeout = null;
 
     this._firstPagePromise = new Promise((resolve) => {
-      const eventBus = this._eventBus;
-      eventBus.on('pagesinit', function onPagesInit() {
-        eventBus.off('pagesinit', onPagesInit);
+      const onPagesInit = () => {
+        if (!this._pdfDocument) {
+          throw new Error(
+            'PDFFindController: `setDocument()` should have been called.');
+        }
+        this._eventBus.off('pagesinit', onPagesInit);
         resolve();
-      });
+      };
+      this._eventBus.on('pagesinit', onPagesInit);
     });
   }