Android license detector in doctor, take two (flutter#14783)

* Revert "Revert "Add android license verification to doctor and some refactoring" (flutter#14727)"

This reverts commit d260294.

* Add tests, fix sdkManagerEnv and use it consistently, and rearrange Status object model

* AnsiSpinner needs to leave the cursor where it found it.

* fix tests

* Const constructor warning only shows up on windows...?

* Avoid crash if we can't find the home directory

* Make pathVarSeparator return a string in the mock

* Implement review comments

* Fix out-of-order problem on stop

Author: jcollins-g

packages/flutter_tools/lib/runner.dart

@@ -234,7 +234,7 @@ Future<String> _doctorText() async {
 
     appContext.setVariable(Logger, logger);
 
-    await appContext.runInZone(() => doctor.diagnose());
+    await appContext.runInZone(() => doctor.diagnose(verbose: true));
 
     return logger.statusText;
   } catch (error, trace) {

packages/flutter_tools/lib/src/android/android_sdk.dart

@@ -12,9 +12,11 @@ import '../base/file_system.dart';
 import '../base/io.dart' show ProcessResult;
 import '../base/os.dart';
 import '../base/platform.dart';
+import '../base/process.dart';
 import '../base/process_manager.dart';
 import '../base/version.dart';
 import '../globals.dart';
+import 'android_studio.dart' as android_studio;
 
 AndroidSdk get androidSdk => context[AndroidSdk];
 
@@ -63,6 +65,9 @@ class AndroidSdk {
     _init();
   }
 
+  static const String _kJavaHomeEnvironmentVariable = 'JAVA_HOME';
+  static const String _kJavaExecutable = 'java';
+
   /// The path to the Android SDK.
   final String directory;
 
@@ -291,11 +296,56 @@ class AndroidSdk {
     return fs.path.join(directory, 'tools', 'bin', 'sdkmanager');
   }
 
+  /// First try Java bundled with Android Studio, then sniff JAVA_HOME, then fallback to PATH.
+  static String findJavaBinary() {
+
+    if (android_studio.javaPath != null)
+      return fs.path.join(android_studio.javaPath, 'bin', 'java');
+
+    final String javaHomeEnv = platform.environment[_kJavaHomeEnvironmentVariable];
+    if (javaHomeEnv != null) {
+      // Trust JAVA_HOME.
+      return fs.path.join(javaHomeEnv, 'bin', 'java');
+    }
+
+    // MacOS specific logic to avoid popping up a dialog window.
+    // See: http://stackoverflow.com/questions/14292698/how-do-i-check-if-the-java-jdk-is-installed-on-mac.
+    if (platform.isMacOS) {
+      try {
+        final String javaHomeOutput = runCheckedSync(<String>['/usr/libexec/java_home'], hideStdout: true);
+        if (javaHomeOutput != null) {
+          final List<String> javaHomeOutputSplit = javaHomeOutput.split('\n');
+          if ((javaHomeOutputSplit != null) && (javaHomeOutputSplit.isNotEmpty)) {
+            final String javaHome = javaHomeOutputSplit[0].trim();
+            return fs.path.join(javaHome, 'bin', 'java');
+          }
+        }
+      } catch (_) { /* ignore */ }
+    }
+
+    // Fallback to PATH based lookup.
+    return os.which(_kJavaExecutable)?.path;
+  }
+
+  Map<String, String> _sdkManagerEnv;
+  Map<String, String> get sdkManagerEnv {
+    if (_sdkManagerEnv == null) {
+      // If we can locate Java, then add it to the path used to run the Android SDK manager.
+      _sdkManagerEnv = <String, String>{};
+      final String javaBinary = findJavaBinary();
+      if (javaBinary != null) {
+        _sdkManagerEnv['PATH'] =
+            fs.path.dirname(javaBinary) + os.pathVarSeparator + platform.environment['PATH'];
+      }
+    }
+    return _sdkManagerEnv;
+  }
+
   /// Returns the version of the Android SDK manager tool or null if not found.
   String get sdkManagerVersion {
     if (!processManager.canRun(sdkManagerPath))
       throwToolExit('Android sdkmanager not found. Update to the latest Android SDK to resolve this.');
-    final ProcessResult result = processManager.runSync(<String>[sdkManagerPath, '--version']);
+    final ProcessResult result = processManager.runSync(<String>[sdkManagerPath, '--version'], environment: sdkManagerEnv);
     if (result.exitCode != 0) {
       throwToolExit('sdkmanager --version failed: ${result.exitCode}', exitCode: result.exitCode);
     }

packages/flutter_tools/lib/src/android/android_studio.dart

@@ -178,14 +178,14 @@ class AndroidStudio implements Comparable<AndroidStudio> {
 
     // Read all $HOME/.AndroidStudio*/system/.home files. There may be several
     // pointing to the same installation, so we grab only the latest one.
-    for (FileSystemEntity entity in fs.directory(homeDirPath).listSync()) {
-      if (entity is Directory && entity.basename.startsWith('.AndroidStudio')) {
-        final AndroidStudio studio = new AndroidStudio.fromHomeDot(entity);
-        if (studio != null &&
-            !_hasStudioAt(studio.directory, newerThan: studio.version)) {
-          studios.removeWhere(
-              (AndroidStudio other) => other.directory == studio.directory);
-          studios.add(studio);
+    if (fs.directory(homeDirPath).existsSync()) {
+      for (FileSystemEntity entity in fs.directory(homeDirPath).listSync()) {
+        if (entity is Directory && entity.basename.startsWith('.AndroidStudio')) {
+          final AndroidStudio studio = new AndroidStudio.fromHomeDot(entity);
+          if (studio != null && !_hasStudioAt(studio.directory, newerThan: studio.version)) {
+            studios.removeWhere((AndroidStudio other) => other.directory == studio.directory);
+            studios.add(studio);
+          }
         }
       }
     }

packages/flutter_tools/lib/src/android/android_workflow.dart

@@ -3,12 +3,11 @@
 // found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert';
 
 import '../base/common.dart';
 import '../base/context.dart';
-import '../base/file_system.dart';
 import '../base/io.dart';
-import '../base/os.dart';
 import '../base/platform.dart';
 import '../base/process.dart';
 import '../base/process_manager.dart';
@@ -17,10 +16,20 @@ import '../base/version.dart';
 import '../doctor.dart';
 import '../globals.dart';
 import 'android_sdk.dart';
-import 'android_studio.dart' as android_studio;
 
 AndroidWorkflow get androidWorkflow => context.putIfAbsent(AndroidWorkflow, () => new AndroidWorkflow());
 
+enum LicensesAccepted {
+  none,
+  some,
+  all,
+  unknown,
+}
+
+final RegExp licenseCounts = new RegExp(r'(\d+) of (\d+) SDK package licenses? not accepted.');
+final RegExp licenseNotAccepted = new RegExp(r'licenses? not accepted', caseSensitive: false);
+final RegExp licenseAccepted = new RegExp(r'All SDK package licenses accepted.');
+
 class AndroidWorkflow extends DoctorValidator implements Workflow {
   AndroidWorkflow() : super('Android toolchain - develop for Android devices');
 
@@ -33,41 +42,8 @@ class AndroidWorkflow extends DoctorValidator implements Workflow {
   @override
   bool get canLaunchDevices => androidSdk != null && androidSdk.validateSdkWellFormed().isEmpty;
 
-  static const String _kJavaHomeEnvironmentVariable = 'JAVA_HOME';
-  static const String _kJavaExecutable = 'java';
   static const String _kJdkDownload = 'https://www.oracle.com/technetwork/java/javase/downloads/';
 
-  /// First try Java bundled with Android Studio, then sniff JAVA_HOME, then fallback to PATH.
-  static String _findJavaBinary() {
-
-    if (android_studio.javaPath != null)
-      return fs.path.join(android_studio.javaPath, 'bin', 'java');
-
-    final String javaHomeEnv = platform.environment[_kJavaHomeEnvironmentVariable];
-    if (javaHomeEnv != null) {
-      // Trust JAVA_HOME.
-      return fs.path.join(javaHomeEnv, 'bin', 'java');
-    }
-
-    // MacOS specific logic to avoid popping up a dialog window.
-    // See: http://stackoverflow.com/questions/14292698/how-do-i-check-if-the-java-jdk-is-installed-on-mac.
-    if (platform.isMacOS) {
-      try {
-        final String javaHomeOutput = runCheckedSync(<String>['/usr/libexec/java_home'], hideStdout: true);
-        if (javaHomeOutput != null) {
-          final List<String> javaHomeOutputSplit = javaHomeOutput.split('\n');
-          if ((javaHomeOutputSplit != null) && (javaHomeOutputSplit.isNotEmpty)) {
-            final String javaHome = javaHomeOutputSplit[0].trim();
-            return fs.path.join(javaHome, 'bin', 'java');
-          }
-        }
-      } catch (_) { /* ignore */ }
-    }
-
-    // Fallback to PATH based lookup.
-    return os.which(_kJavaExecutable)?.path;
-  }
-
   /// Returns false if we cannot determine the Java version or if the version
   /// is not compatible.
   bool _checkJavaVersion(String javaBinary, List<ValidationMessage> messages) {
@@ -154,7 +130,7 @@ class AndroidWorkflow extends DoctorValidator implements Workflow {
     }
 
     // Now check for the JDK.
-    final String javaBinary = _findJavaBinary();
+    final String javaBinary = AndroidSdk.findJavaBinary();
     if (javaBinary == null) {
       messages.add(new ValidationMessage.error(
           'No Java Development Kit (JDK) found; You must have the environment '
@@ -169,25 +145,66 @@ class AndroidWorkflow extends DoctorValidator implements Workflow {
       return new ValidationResult(ValidationType.partial, messages, statusInfo: sdkVersionText);
     }
 
+    // Check for licenses.
+    switch (await licensesAccepted) {
+      case LicensesAccepted.all:
+        messages.add(new ValidationMessage('All Android licenses accepted.'));
+        break;
+      case LicensesAccepted.some:
+        messages.add(new ValidationMessage.hint('Some Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses'));
+        return new ValidationResult(ValidationType.partial, messages, statusInfo: sdkVersionText);
+      case LicensesAccepted.none:
+        messages.add(new ValidationMessage.error('Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses'));
+        return new ValidationResult(ValidationType.partial, messages, statusInfo: sdkVersionText);
+      case LicensesAccepted.unknown:
+        messages.add(new ValidationMessage.error('Android license status unknown.'));
+        return new ValidationResult(ValidationType.partial, messages, statusInfo: sdkVersionText);
+    }
+
     // Success.
     return new ValidationResult(ValidationType.installed, messages, statusInfo: sdkVersionText);
   }
 
+  Future<LicensesAccepted> get licensesAccepted async {
+    LicensesAccepted status = LicensesAccepted.unknown;
+
+    void _onLine(String line) {
+      if (licenseAccepted.hasMatch(line)) {
+        status = LicensesAccepted.all;
+      } else if (licenseCounts.hasMatch(line)) {
+        final Match match = licenseCounts.firstMatch(line);
+        if (match.group(1) != match.group(2)) {
+          status = LicensesAccepted.some;
+        } else {
+          status = LicensesAccepted.none;
+        }
+      } else if (licenseNotAccepted.hasMatch(line)) {
+        // In case the format changes, a more general match will keep doctor
+        // mostly working.
+        status = LicensesAccepted.none;
+      }
+    }
+
+    final Process process = await runCommand(<String>[androidSdk.sdkManagerPath, '--licenses'], environment: androidSdk.sdkManagerEnv);
+    process.stdin.write('n\n');
+    final Future<void> output = process.stdout.transform(const Utf8Decoder(allowMalformed: true)).transform(const LineSplitter()).listen(_onLine).asFuture<void>(null);
+    final Future<void> errors = process.stderr.transform(const Utf8Decoder(allowMalformed: true)).transform(const LineSplitter()).listen(_onLine).asFuture<void>(null);
+    try {
+      await Future.wait<void>(<Future<void>>[output, errors]).timeout(const Duration(seconds: 30));
+    } catch (TimeoutException) {
+      printTrace('Intentionally killing ${androidSdk.sdkManagerPath}');
+      processManager.killPid(process.pid);
+    }
+    return status;
+  }
+
   /// Run the Android SDK manager tool in order to accept SDK licenses.
   static Future<bool> runLicenseManager() async {
     if (androidSdk == null) {
       printStatus('Unable to locate Android SDK.');
       return false;
     }
 
-    // If we can locate Java, then add it to the path used to run the Android SDK manager.
-    final Map<String, String> sdkManagerEnv = <String, String>{};
-    final String javaBinary = _findJavaBinary();
-    if (javaBinary != null) {
-      sdkManagerEnv['PATH'] =
-          fs.path.dirname(javaBinary) + os.pathVarSeparator + platform.environment['PATH'];
-    }
-
     if (!processManager.canRun(androidSdk.sdkManagerPath))
       throwToolExit(
         'Android sdkmanager tool not found.\n'
@@ -205,7 +222,7 @@ class AndroidWorkflow extends DoctorValidator implements Workflow {
 
     final Process process = await runCommand(
       <String>[androidSdk.sdkManagerPath, '--licenses'],
-      environment: sdkManagerEnv,
+      environment: androidSdk.sdkManagerEnv,
     );
 
     waitGroup<Null>(<Future<Null>>[