Fixed slow load of flashcard modal (bug introduced in 1.12.0) (#926)

* Possibly fixed, for beta testing

* Added logging of detailed timing debug

* Problem fixed, still needs tidy up

* Removed detailed timing logging

* Removed detailed timing logging

* lint, format and update change log

* Removed unused code caught by test coverage checks

CHANGELOG.md

@@ -1 +1 @@
-docs/changelog.md
+docs/changelog.md

CONTRIBUTING.md

@@ -1 +1 @@
-docs/en/contributing.md
+docs/en/contributing.md

docs/changelog.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file. Dates are d
 
 Generated by [`auto-changelog`](https://github.com/CookPete/auto-changelog).
 
+#### [Unreleased]
+
+-   [BUG] Very slow load of flashcard modal (since 1.11.2) [`#914`](https://github.com/st3v3nmw/obsidian-spaced-repetition/issues/914)
+
 #### [1.12.2](https://github.com/st3v3nmw/obsidian-spaced-repetition/compare/1.12.1...1.12.2)
 
 -   fix bug with recognizing frontmatter topic tags (led to missing cards shown for review) [`#920`](https://github.com/st3v3nmw/obsidian-spaced-repetition/pull/920)

src/NoteQuestionParser.ts

@@ -30,15 +30,21 @@ export class NoteQuestionParser {
         onlyKeepQuestionsWithTopicPath: boolean,
     ): Promise<Question[]> {
         this.noteFile = noteFile;
-        const noteText: string = await noteFile.read();
-
-        // Get the list of tags, and analyse for the topic list
-        const tagCacheList: TagCache[] = noteFile.getAllTagsFromText();
-
-        const hasTopicPaths =
-            tagCacheList.some((item) => SettingsUtil.isFlashcardTag(this.settings, item.tag)) ||
+        // For efficiency, we first get the tag list from the Obsidian cache
+        // (this only gives the tag names, not the line numbers, but this is sufficient for this first step)
+        const tagCacheList: string[] = noteFile.getAllTagsFromCache();
+        const hasTopicPaths: boolean =
+            tagCacheList.some((item) => SettingsUtil.isFlashcardTag(this.settings, item)) ||
             folderTopicPath.hasPath;
+
         if (hasTopicPaths) {
+            // Reading the file is relatively an expensive operation, so we only do this when needed
+            const noteText: string = await noteFile.read();
+
+            // Now that we know there are relevant flashcard tags in the file, we can get the more detailed info
+            // that includes the line numbers of each tag
+            const tagCompleteList: TagCache[] = noteFile.getAllTagsFromText();
+
             // The following analysis can require fair computation.
             // There is no point doing it if there aren't any topic paths
 
@@ -51,7 +57,7 @@ export class NoteQuestionParser {
 
             // For each question, determine it's TopicPathList
             [this.frontmatterTopicPathList, this.contentTopicPathInfo] =
-                this.analyseTagCacheList(tagCacheList);
+                this.analyseTagCacheList(tagCompleteList);
             for (const question of this.questionList) {
                 question.topicPathList = this.determineQuestionTopicPathList(question);
             }

src/SRFile.ts

@@ -1,9 +1,18 @@
-import { MetadataCache, TFile, Vault, HeadingCache, TagCache, FrontMatterCache } from "obsidian";
+import {
+    MetadataCache,
+    TFile,
+    Vault,
+    HeadingCache,
+    getAllTags as ObsidianGetAllTags,
+    TagCache,
+    FrontMatterCache,
+} from "obsidian";
 import { parseObsidianFrontmatterTag } from "./util/utils";
 
 export interface ISRFile {
     get path(): string;
     get basename(): string;
+    getAllTagsFromCache(): string[];
     getAllTagsFromText(): TagCache[];
     getQuestionContext(cardLine: number): string[];
     read(): Promise<string>;
@@ -29,6 +38,12 @@ export class SrTFile implements ISRFile {
         return this.file.basename;
     }
 
+    getAllTagsFromCache(): string[] {
+        const fileCachedData = this.metadataCache.getFileCache(this.file) || {};
+        const result: string[] = ObsidianGetAllTags(fileCachedData) || [];
+        return result;
+    }
+
     getAllTagsFromText(): TagCache[] {
         const result: TagCache[] = [] as TagCache[];
         const fileCachedData = this.metadataCache.getFileCache(this.file) || {};

src/util/TimeTestUtil.ts

@@ -0,0 +1,31 @@
+import moment from "moment";
+
+// These functions were used to diagnose performance issue
+// https://github.com/st3v3nmw/obsidian-spaced-repetition/issues/914
+
+let testTimeInfo: [string, number][];
+
+export function testTimeStart(): void {
+    testTimeInfo = [["Start", moment().valueOf()]];
+}
+
+export function testTimeLog(desc: string): void {
+    if (testTimeInfo == null) testTimeStart();
+    testTimeInfo.push([desc, moment().valueOf()]);
+}
+
+export function testTimeGetLapTime(): number {
+    return moment().valueOf() - testTimeInfo[0][1];
+}
+
+export function testTimeFormatLapInfo(): string {
+    let prevTime: number = testTimeInfo[0][1];
+    let result: string = "";
+    for (let i = 1; i < testTimeInfo.length; i++) {
+        const thisTime: number = testTimeInfo[i][1];
+        result += `\t${testTimeInfo[i][0]}\t${thisTime - prevTime}`;
+        prevTime = thisTime;
+    }
+    result += `\tLapTime\t${testTimeGetLapTime()}|`;
+    return result;
+}

tests/unit/helpers/UnitTestHelper.ts

@@ -55,10 +55,3 @@ export function unitTest_GetAllTagsFromTextEx(text: string): TagCache[] {
     }
     return result;
 }
-
-export function unitTest_GetAllTagsFromText(text: string): string[] {
-    const tagRegex = /#[^\s#]+/gi;
-    const result: RegExpMatchArray = text.match(tagRegex);
-    if (!result) return [];
-    return result;
-}

tests/unit/helpers/UnitTestSRFile.ts

@@ -19,6 +19,10 @@ export class UnitTestSRFile implements ISRFile {
         return "";
     }
 
+    getAllTagsFromCache(): string[] {
+        return unitTest_GetAllTagsFromTextEx(this.content).map((item) => item.tag);
+    }
+
     getAllTagsFromText(): TagCache[] {
         return unitTest_GetAllTagsFromTextEx(this.content);
     }