Bug 1769585: Introduce a pref that the minimum char length to enable adaptive history autofill. r=adw

Differential Revision: https://phabricator.services.mozilla.com/D146654

browser/components/urlbar/UrlbarPrefs.jsm

@@ -50,6 +50,9 @@ const PREF_URLBAR_DEFAULTS = new Map([
   // Nimbus variable `autoFillAdaptiveHistoryEnabled`.
   ["autoFill.adaptiveHistory.enabled", false],
 
+  // Minimum char length to enable adaptive history autofill.
+  ["autoFill.adaptiveHistory.minCharsThreshold", 0],
+
   // Threshold for use count of input history that we handle as adaptive history
   // autofill. If the use count is this value or more, it will be a candidate.
   // Set the threshold to not be candidate the input history passed

browser/components/urlbar/UrlbarProviderAutofill.jsm

@@ -752,7 +752,11 @@ class ProviderAutofill extends UrlbarProvider {
     }
 
     // We try to autofill with adaptive history first.
-    if (UrlbarPrefs.get("autoFillAdaptiveHistoryEnabled")) {
+    if (
+      UrlbarPrefs.get("autoFillAdaptiveHistoryEnabled") &&
+      UrlbarPrefs.get("autoFill.adaptiveHistory.minCharsThreshold") <=
+        queryContext.searchString.length
+    ) {
       const [query, params] = this._getAdaptiveHistoryQuery(queryContext);
       if (query) {
         const resultSet = await conn.executeCached(query, params);

browser/components/urlbar/tests/unit/test_autofill_adaptiveHistory.js

@@ -745,6 +745,71 @@ const TEST_DATA = [
       ],
     },
   },
+  {
+    description: "minCharsThreshold pref equals to the user input length",
+    pref: true,
+    minCharsThreshold: 3,
+    visitHistory: ["http://example.com/test"],
+    inputHistory: [{ uri: "http://example.com/test", input: "exa" }],
+    userInput: "exa",
+    expected: {
+      autofilled: "example.com/test",
+      completed: "http://example.com/test",
+      results: [
+        context =>
+          makeVisitResult(context, {
+            uri: "http://example.com/test",
+            title: "example.com/test",
+            heuristic: true,
+          }),
+      ],
+    },
+  },
+  {
+    description: "minCharsThreshold pref is smaller than the user input length",
+    pref: true,
+    minCharsThreshold: 2,
+    visitHistory: ["http://example.com/test"],
+    inputHistory: [{ uri: "http://example.com/test", input: "exa" }],
+    userInput: "exa",
+    expected: {
+      autofilled: "example.com/test",
+      completed: "http://example.com/test",
+      results: [
+        context =>
+          makeVisitResult(context, {
+            uri: "http://example.com/test",
+            title: "example.com/test",
+            heuristic: true,
+          }),
+      ],
+    },
+  },
+  {
+    description: "minCharsThreshold pref is larger than the user input length",
+    pref: true,
+    minCharsThreshold: 4,
+    visitHistory: ["http://example.com/test"],
+    inputHistory: [{ uri: "http://example.com/test", input: "exa" }],
+    userInput: "exa",
+    expected: {
+      autofilled: "example.com/",
+      completed: "http://example.com/",
+      results: [
+        context =>
+          makeVisitResult(context, {
+            uri: "http://example.com/",
+            title: "example.com",
+            heuristic: true,
+          }),
+        context =>
+          makeVisitResult(context, {
+            uri: "http://example.com/test",
+            title: "test visit for http://example.com/test",
+          }),
+      ],
+    },
+  },
   {
     description: "Turn the pref off",
     pref: false,
@@ -775,6 +840,7 @@ add_task(async function inputTest() {
   for (const {
     description,
     pref,
+    minCharsThreshold,
     useCountThreshold,
     source,
     visitHistory,
@@ -787,6 +853,13 @@ add_task(async function inputTest() {
 
     UrlbarPrefs.set("autoFill.adaptiveHistory.enabled", pref);
 
+    if (!isNaN(minCharsThreshold)) {
+      UrlbarPrefs.set(
+        "autoFill.adaptiveHistory.minCharsThreshold",
+        minCharsThreshold
+      );
+    }
+
     if (!isNaN(useCountThreshold)) {
       UrlbarPrefs.set(
         "autoFill.adaptiveHistory.useCountThreshold",
@@ -825,6 +898,7 @@ add_task(async function inputTest() {
 
     await cleanupPlaces();
     UrlbarPrefs.clear("autoFill.adaptiveHistory.enabled");
+    UrlbarPrefs.clear("autoFill.adaptiveHistory.minCharsThreshold");
     UrlbarPrefs.clear("autoFill.adaptiveHistory.useCountThreshold");
   }
 });