Search suffix tree implementation

src/CONST.ts

@@ -1100,6 +1100,9 @@ const CONST = {
         SEARCH_OPTION_LIST_DEBOUNCE_TIME: 300,
         RESIZE_DEBOUNCE_TIME: 100,
         UNREAD_UPDATE_DEBOUNCE_TIME: 300,
+        SEARCH_CONVERT_SEARCH_VALUES: 'search_convert_search_values',
+        SEARCH_MAKE_TREE: 'search_make_tree',
+        SEARCH_BUILD_TREE: 'search_build_tree',
         SEARCH_FILTER_OPTIONS: 'search_filter_options',
         USE_DEBOUNCED_STATE_DELAY: 300,
     },

src/components/Search/SearchRouter/SearchRouter.tsx

@@ -1,3 +1,4 @@
+/* eslint-disable rulesdir/prefer-at */
 import {useNavigationState} from '@react-navigation/native';
 import debounce from 'lodash/debounce';
 import React, {useCallback, useEffect, useMemo, useRef, useState} from 'react';
@@ -14,6 +15,8 @@ import useKeyboardShortcut from '@hooks/useKeyboardShortcut';
 import useLocalize from '@hooks/useLocalize';
 import useResponsiveLayout from '@hooks/useResponsiveLayout';
 import useThemeStyles from '@hooks/useThemeStyles';
+import Timing from '@libs/actions/Timing';
+import FastSearch from '@libs/FastSearch';
 import Log from '@libs/Log';
 import * as OptionsListUtils from '@libs/OptionsListUtils';
 import type {OptionData} from '@libs/ReportUtils';
@@ -58,6 +61,49 @@ function SearchRouter() {
         return OptionsListUtils.getSearchOptions(options, '', betas ?? []);
     }, [areOptionsInitialized, betas, options]);
 
+    /**
+     * Builds a suffix tree and returns a function to search in it.
+     */
+    const findInSearchTree = useMemo(() => {
+        const fastSearch = FastSearch.createFastSearch([
+            {
+                data: searchOptions.personalDetails,
+                toSearchableString: (option) => {
+                    const displayName = option.participantsList?.[0]?.displayName ?? '';
+                    return [option.login ?? '', option.login !== displayName ? displayName : ''].join();
+                },
+            },
+            {
+                data: searchOptions.recentReports,
+                toSearchableString: (option) => {
+                    const searchStringForTree = [option.text ?? '', option.login ?? ''];
+
+                    if (option.isThread) {
+                        if (option.alternateText) {
+                            searchStringForTree.push(option.alternateText);
+                        }
+                    } else if (!!option.isChatRoom || !!option.isPolicyExpenseChat) {
+                        if (option.subtitle) {
+                            searchStringForTree.push(option.subtitle);
+                        }
+                    }
+
+                    return searchStringForTree.join();
+                },
+            },
+        ]);
+        function search(searchInput: string) {
+            const [personalDetails, recentReports] = fastSearch.search(searchInput);
+
+            return {
+                personalDetails,
+                recentReports,
+            };
+        }
+
+        return search;
+    }, [searchOptions.personalDetails, searchOptions.recentReports]);
+
     const filteredOptions = useMemo(() => {
         if (debouncedInputValue.trim() === '') {
             return {
@@ -67,14 +113,26 @@ function SearchRouter() {
             };
         }
 
-        const newOptions = OptionsListUtils.filterOptions(searchOptions, debouncedInputValue, {sortByReportTypeInSearch: true, preferChatroomsOverThreads: true});
+        Timing.start(CONST.TIMING.SEARCH_FILTER_OPTIONS);
+        const newOptions = findInSearchTree(debouncedInputValue);
+        Timing.end(CONST.TIMING.SEARCH_FILTER_OPTIONS);
 
-        return {
+        const recentReports = newOptions.recentReports.concat(newOptions.personalDetails);
+
+        const userToInvite = OptionsListUtils.pickUserToInvite({
+            canInviteUser: true,
             recentReports: newOptions.recentReports,
             personalDetails: newOptions.personalDetails,
-            userToInvite: newOptions.userToInvite,
+            searchValue: debouncedInputValue,
+            optionsToExclude: [{login: CONST.EMAIL.NOTIFICATIONS}],
+        });
+
+        return {
+            recentReports,
+            personalDetails: [],
+            userToInvite,
         };
-    }, [debouncedInputValue, searchOptions]);
+    }, [debouncedInputValue, findInSearchTree]);
 
     const recentReports: OptionData[] = useMemo(() => {
         const currentSearchOptions = debouncedInputValue === '' ? searchOptions : filteredOptions;

src/libs/FastSearch.ts

@@ -0,0 +1,140 @@
+/* eslint-disable rulesdir/prefer-at */
+import CONST from '@src/CONST';
+import Timing from './actions/Timing';
+import SuffixUkkonenTree from './SuffixUkkonenTree';
+
+type SearchableData<T> = {
+    /**
+     * The data that should be searchable
+     */
+    data: T[];
+    /**
+     * A function that generates a string from a data entry. The string's value is used for searching.
+     * If you have multiple fields that should be searchable, simply concat them to the string and return it.
+     */
+    toSearchableString: (data: T) => string;
+};
+
+// There are certain characters appear very often in our search data (email addresses), which we don't need to search for.
+const charSetToSkip = new Set(['@', '.', '#', '$', '%', '&', '*', '+', '-', '/', ':', ';', '<', '=', '>', '?', '_', '~', '!', ' ']);
+
+/**
+ * Creates a new "FastSearch" instance. "FastSearch" uses a suffix tree to search for (sub-)strings in a list of strings.
+ * You can provide multiple datasets. The search results will be returned for each dataset.
+ *
+ * Note: Creating a FastSearch instance with a lot of data is computationally expensive. You should create an instance once and reuse it.
+ * Searches will be very fast though, even with a lot of data.
+ */
+function createFastSearch<T>(dataSets: Array<SearchableData<T>>) {
+    Timing.start(CONST.TIMING.SEARCH_CONVERT_SEARCH_VALUES);
+    const maxNumericListSize = 400_000;
+    // The user might provide multiple data sets, but internally, the search values will be stored in this one list:
+    let concatenatedNumericList = new Uint8Array(maxNumericListSize);
+    // Here we store the index of the data item in the original data list, so we can map the found occurrences back to the original data:
+    const occurrenceToIndex = new Uint32Array(maxNumericListSize * 4);
+    // As we are working with ArrayBuffers, we need to keep track of the current offset:
+    const offset = {value: 1};
+    // We store the last offset for a dataSet, so we can map the found occurrences to the correct dataSet:
+    const listOffsets: number[] = [];
+
+    for (const {data, toSearchableString} of dataSets) {
+        // Performance critical: the array parameters are passed by reference, so we don't have to create new arrays every time:
+        dataToNumericRepresentation(concatenatedNumericList, occurrenceToIndex, offset, {data, toSearchableString});
+        listOffsets.push(offset.value);
+    }
+    concatenatedNumericList[offset.value++] = SuffixUkkonenTree.END_CHAR_CODE;
+    listOffsets[listOffsets.length - 1] = offset.value;
+    Timing.end(CONST.TIMING.SEARCH_CONVERT_SEARCH_VALUES);
+
+    // The list might be larger than necessary, so we clamp it to the actual size:
+    concatenatedNumericList = concatenatedNumericList.slice(0, offset.value);
+
+    // Create & build the suffix tree:
+    Timing.start(CONST.TIMING.SEARCH_MAKE_TREE);
+    const tree = SuffixUkkonenTree.makeTree(concatenatedNumericList);
+    Timing.end(CONST.TIMING.SEARCH_MAKE_TREE);
+
+    Timing.start(CONST.TIMING.SEARCH_BUILD_TREE);
+    tree.build();
+    Timing.end(CONST.TIMING.SEARCH_BUILD_TREE);
+
+    /**
+     * Searches for the given input and returns results for each dataset.
+     */
+    function search(searchInput: string): T[][] {
+        const cleanedSearchString = cleanString(searchInput);
+        const {numeric} = SuffixUkkonenTree.stringToNumeric(cleanedSearchString, {
+            charSetToSkip,
+            // stringToNumeric might return a list that is larger than necessary, so we clamp it to the actual size
+            // (otherwise the search could fail as we include in our search empty array values):
+            clamp: true,
+        });
+        const result = tree.findSubstring(Array.from(numeric));
+
+        const resultsByDataSet = Array.from({length: dataSets.length}, () => new Set<T>());
+        // eslint-disable-next-line @typescript-eslint/prefer-for-of
+        for (let i = 0; i < result.length; i++) {
+            const occurrenceIndex = result[i];
+            const itemIndexInDataSet = occurrenceToIndex[occurrenceIndex];
+            const dataSetIndex = listOffsets.findIndex((listOffset) => occurrenceIndex < listOffset);
+
+            if (dataSetIndex === -1) {
+                throw new Error('Programmatic error, this should never ever happen');
+            }
+            const item = dataSets[dataSetIndex].data[itemIndexInDataSet];
+            if (!item) {
+                throw new Error('Programmatic error, this should never ever happen');
+            }
+            resultsByDataSet[dataSetIndex].add(item);
+        }
+
+        return resultsByDataSet.map((set) => Array.from(set));
+    }
+
+    return {
+        search,
+    };
+}
+
+/**
+ * The suffix tree can only store string like values, and internally stores those as numbers.
+ * This function converts the user data (which are most likely objects) to a numeric representation.
+ * Additionally a list of the original data and their index position in the numeric list is created, which is used to map the found occurrences back to the original data.
+ */
+function dataToNumericRepresentation<T>(concatenatedNumericList: Uint8Array, occurrenceToIndex: Uint32Array, offset: {value: number}, {data, toSearchableString}: SearchableData<T>): void {
+    data.forEach((option, index) => {
+        const searchStringForTree = toSearchableString(option);
+        const cleanedSearchStringForTree = cleanString(searchStringForTree);
+
+        if (cleanedSearchStringForTree.length === 0) {
+            return;
+        }
+
+        SuffixUkkonenTree.stringToNumeric(cleanedSearchStringForTree, {
+            charSetToSkip,
+            out: {
+                outArray: concatenatedNumericList,
+                offset,
+                outOccurrenceToIndex: occurrenceToIndex,
+                index,
+            },
+        });
+        // eslint-disable-next-line no-param-reassign
+        occurrenceToIndex[offset.value] = index;
+        // eslint-disable-next-line no-param-reassign
+        concatenatedNumericList[offset.value++] = SuffixUkkonenTree.DELIMITER_CHAR_CODE;
+    });
+}
+
+/**
+ * Everything in the tree is treated as lowercase.
+ */
+function cleanString(input: string) {
+    return input.toLowerCase();
+}
+
+const FastSearch = {
+    createFastSearch,
+};
+
+export default FastSearch;

src/libs/OptionsListUtils.ts

@@ -2452,6 +2452,31 @@ function getPersonalDetailSearchTerms(item: Partial<ReportUtils.OptionData>) {
 function getCurrentUserSearchTerms(item: ReportUtils.OptionData) {
     return [item.text ?? '', item.login ?? '', item.login?.replace(CONST.EMAIL_SEARCH_REGEX, '') ?? ''];
 }
+
+type PickUserToInviteParams = {
+    canInviteUser: boolean;
+    recentReports: ReportUtils.OptionData[];
+    personalDetails: ReportUtils.OptionData[];
+    searchValue: string;
+    config?: FilterOptionsConfig;
+    optionsToExclude: Option[];
+};
+
+const pickUserToInvite = ({canInviteUser, recentReports, personalDetails, searchValue, config, optionsToExclude}: PickUserToInviteParams) => {
+    let userToInvite = null;
+    if (canInviteUser) {
+        if (recentReports.length === 0 && personalDetails.length === 0) {
+            userToInvite = getUserToInviteOption({
+                searchValue,
+                selectedOptions: config?.selectedOptions,
+                optionsToExclude,
+            });
+        }
+    }
+
+    return userToInvite;
+};
+
 /**
  * Filters options based on the search input value
  */
@@ -2528,16 +2553,7 @@ function filterOptions(options: Options, searchInputValue: string, config?: Filt
         recentReports = orderOptions(recentReports, searchValue);
     }
 
-    let userToInvite = null;
-    if (canInviteUser) {
-        if (recentReports.length === 0 && personalDetails.length === 0) {
-            userToInvite = getUserToInviteOption({
-                searchValue,
-                selectedOptions: config?.selectedOptions,
-                optionsToExclude,
-            });
-        }
-    }
+    const userToInvite = pickUserToInvite({canInviteUser, recentReports, personalDetails, searchValue, config, optionsToExclude});
 
     if (maxRecentReportsToShow > 0 && recentReports.length > maxRecentReportsToShow) {
         recentReports.splice(maxRecentReportsToShow);
@@ -2606,6 +2622,7 @@ export {
     formatMemberForList,
     formatSectionsFromSearchTerm,
     getShareLogOptions,
+    orderOptions,
     filterOptions,
     createOptionList,
     createOptionFromReport,
@@ -2620,6 +2637,7 @@ export {
     getEmptyOptions,
     shouldUseBoldText,
     getAlternateText,
+    pickUserToInvite,
 };
 
 export type {MemberForList, CategorySection, CategoryTreeSection, Options, OptionList, SearchOption, PayeePersonalDetails, Category, Tax, TaxRatesOption, Option, OptionTree};