From 819e52cab3823c4a8e900f0f5ece87fcb8a34d4c Mon Sep 17 00:00:00 2001
From: wb9688 <wb9688@users.noreply.github.com>
Date: Fri, 27 Mar 2020 20:45:26 +0100
Subject: [PATCH] Check code style with Checkstyle

---
 app/build.gradle |  46 +++++++++++-
 checkstyle.xml   | 184 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 229 insertions(+), 1 deletion(-)
 create mode 100644 checkstyle.xml

diff --git a/app/build.gradle b/app/build.gradle
index 92c00c372..893885c6d 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -2,6 +2,7 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
 apply plugin: 'kotlin-kapt'
+apply plugin: 'checkstyle'
 
 android {
     compileSdkVersion 28
@@ -81,11 +82,54 @@ ext {
     icepickLibVersion = '3.2.0'
     stethoLibVersion = '1.5.0'
     markwonVersion = '4.2.1'
+    checkstyleVersion = '8.31'
 }
 
+checkstyle {
+    configFile rootProject.file('checkstyle.xml')
+    ignoreFailures false
+    showViolations true
+    toolVersion = "${checkstyleVersion}"
+}
+
+task runCheckstyle(type: Checkstyle) {
+    source 'src'
+    include '**/*.java'
+    exclude '**/gen/**'
+    exclude '**/R.java'
+    exclude '**/BuildConfig.java'
+    exclude 'main/java/us/shandian/giga/**'
+    exclude 'main/java/org/schabi/newpipe/streams/**'
+
+    // empty classpath
+    classpath = files()
+
+    showViolations true
+
+    reports {
+        xml.enabled true
+        html.enabled true
+    }
+}
+
+tasks.withType(Checkstyle).each {
+    checkstyleTask -> checkstyleTask.doLast {
+        reports.all { report ->
+            def outputFile = report.destination
+            if (outputFile.exists() && outputFile.text.contains("severity=\"error\"")) {
+                throw new GradleException("There were checkstyle errors! For more info check $outputFile")
+            }
+        }
+    }
+}
+
+preBuild.dependsOn runCheckstyle
+
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 
+    implementation "com.puppycrawl.tools:checkstyle:${checkstyleVersion}"
+
     androidTestImplementation 'androidx.test.ext:junit:1.1.1'
     androidTestImplementation "android.arch.persistence.room:testing:1.1.1"
     androidTestImplementation('androidx.test.espresso:espresso-core:3.1.0', {
@@ -164,4 +208,4 @@ static String getGitWorkingBranch() {
         // git was not found
         return ""
     }
-}
\ No newline at end of file
+}
diff --git a/checkstyle.xml b/checkstyle.xml
new file mode 100644
index 000000000..8968d57c6
--- /dev/null
+++ b/checkstyle.xml
@@ -0,0 +1,184 @@
+<?xml version="1.0"?>
+<!DOCTYPE module PUBLIC
+          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+          "https://checkstyle.org/dtds/configuration_1_3.dtd">
+<module name="Checker">
+    <!--
+        If you set the basedir property below, then all reported file
+        names will be relative to the specified directory. See
+        https://checkstyle.org/5.x/config.html#Checker
+
+        <property name="basedir" value="${basedir}"/>
+    -->
+    <property name="severity" value="error"/>
+
+    <property name="fileExtensions" value="java, properties, xml"/>
+
+    <!-- Excludes all 'module-info.java' files              -->
+    <!-- See https://checkstyle.org/config_filefilters.html -->
+    <module name="BeforeExecutionExclusionFileFilter">
+        <property name="fileNamePattern" value="module\-info\.java$"/>
+    </module>
+
+    <!-- https://checkstyle.org/config_filters.html#SuppressionFilter -->
+    <module name="SuppressionFilter">
+        <property name="file" value="${org.checkstyle.sun.suppressionfilter.config}"
+                  default="checkstyle-suppressions.xml" />
+        <property name="optional" value="true"/>
+    </module>
+
+    <!-- Checks that a package-info.java file exists for each package.     -->
+    <!-- See https://checkstyle.org/config_javadoc.html#JavadocPackage -->
+    <!--<module name="JavadocPackage"/>-->
+
+    <!-- Checks whether files end with a new line.                        -->
+    <!-- See https://checkstyle.org/config_misc.html#NewlineAtEndOfFile -->
+    <module name="NewlineAtEndOfFile"/>
+
+    <!-- Checks that property files contain the same keys.         -->
+    <!-- See https://checkstyle.org/config_misc.html#Translation -->
+    <module name="Translation"/>
+
+    <!-- Checks for Size Violations.                    -->
+    <!-- See https://checkstyle.org/config_sizes.html -->
+    <module name="FileLength"/>
+    <module name="LineLength">
+      <property name="max" value="100"/>
+      <property name="fileExtensions" value="java"/>
+    </module>
+
+    <!-- Checks for whitespace                               -->
+    <!-- See https://checkstyle.org/config_whitespace.html -->
+    <module name="FileTabCharacter"/>
+
+    <!-- Miscellaneous other checks.                   -->
+    <!-- See https://checkstyle.org/config_misc.html -->
+    <module name="RegexpSingleline">
+       <property name="format" value="\s+$"/>
+       <property name="minimum" value="0"/>
+       <property name="maximum" value="0"/>
+       <property name="message" value="Line has trailing spaces."/>
+    </module>
+
+    <!-- Checks for Headers                                -->
+    <!-- See https://checkstyle.org/config_header.html   -->
+    <!-- <module name="Header"> -->
+    <!--   <property name="headerFile" value="${checkstyle.header.file}"/> -->
+    <!--   <property name="fileExtensions" value="java"/> -->
+    <!-- </module> -->
+
+    <module name="TreeWalker">
+        <!-- Checks for Javadoc comments.                     -->
+        <!-- See https://checkstyle.org/config_javadoc.html -->
+        <module name="InvalidJavadocPosition"/>
+        <module name="JavadocMethod"/>
+        <module name="JavadocType"/>
+        <!--<module name="JavadocVariable"/>-->
+        <module name="JavadocStyle"/>
+        <!--<module name="MissingJavadocMethod"/>-->
+
+        <!-- Checks for Naming Conventions.                  -->
+        <!-- See https://checkstyle.org/config_naming.html -->
+        <module name="ConstantName"/>
+        <module name="LocalFinalVariableName"/>
+        <module name="LocalVariableName"/>
+        <module name="MemberName">
+            <property name="format" value="^(TAG|DEBUG|[a-z][a-zA-Z0-9]*)$"/>
+        </module>
+        <module name="MethodName"/>
+        <module name="PackageName"/>
+        <module name="ParameterName"/>
+        <module name="StaticVariableName"/>
+        <module name="TypeName"/>
+
+        <!-- Checks for imports                              -->
+        <!-- See https://checkstyle.org/config_import.html -->
+        <module name="AvoidStarImport"/>
+        <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
+        <module name="RedundantImport"/>
+        <module name="UnusedImports"/>
+
+        <!-- Checks for Size Violations.                    -->
+        <!-- See https://checkstyle.org/config_sizes.html -->
+        <module name="MethodLength">
+            <property name="severity" value="warning"/>
+        </module>
+        <module name="ParameterNumber">
+            <property name="severity" value="warning"/>
+        </module>
+
+        <!-- Checks for whitespace                               -->
+        <!-- See https://checkstyle.org/config_whitespace.html -->
+        <module name="EmptyForIteratorPad"/>
+        <module name="GenericWhitespace"/>
+        <module name="MethodParamPad"/>
+        <module name="NoWhitespaceAfter"/>
+        <module name="NoWhitespaceBefore"/>
+        <module name="OperatorWrap"/>
+        <module name="ParenPad"/>
+        <module name="TypecastParenPad"/>
+        <module name="WhitespaceAfter"/>
+        <module name="WhitespaceAround"/>
+
+        <!-- Modifier Checks                                    -->
+        <!-- See https://checkstyle.org/config_modifiers.html -->
+        <module name="ModifierOrder"/>
+        <module name="RedundantModifier"/>
+
+        <!-- Checks for blocks. You know, those {}'s         -->
+        <!-- See https://checkstyle.org/config_blocks.html -->
+        <module name="AvoidNestedBlocks"/>
+        <module name="EmptyBlock"/>
+        <module name="LeftCurly"/>
+        <module name="NeedBraces"/>
+        <module name="RightCurly"/>
+
+        <!-- Checks for common coding problems               -->
+        <!-- See https://checkstyle.org/config_coding.html -->
+        <module name="EmptyStatement"/>
+        <module name="EqualsHashCode">
+            <property name="severity" value="warning"/>
+        </module>
+        <module name="HiddenField">
+            <property name="ignoreConstructorParameter" value="true"/>
+            <property name="ignoreSetter" value="true"/>
+        </module>
+        <module name="IllegalInstantiation"/>
+        <module name="InnerAssignment"/>
+        <!--<module name="MagicNumber"/>-->
+        <module name="MissingSwitchDefault">
+            <property name="severity" value="warning"/>
+        </module>
+        <module name="MultipleVariableDeclarations"/>
+        <module name="SimplifyBooleanExpression"/>
+        <module name="SimplifyBooleanReturn"/>
+
+        <!-- Checks for class design                         -->
+        <!-- See https://checkstyle.org/config_design.html -->
+        <!--<module name="DesignForExtension"/>-->
+        <module name="FinalClass"/>
+        <module name="HideUtilityClassConstructor"/>
+        <module name="InterfaceIsType"/>
+        <module name="VisibilityModifier">
+            <property name="ignoreAnnotationCanonicalNames" value="State,ColumnInfo"/>
+            <property name="severity" value="warning"/>
+        </module>
+
+        <!-- Miscellaneous other checks.                   -->
+        <!-- See https://checkstyle.org/config_misc.html -->
+        <module name="ArrayTypeStyle"/>
+        <module name="FinalParameters"/>
+        <module name="TodoComment">
+            <property name="format" value="(TODO:|FIXME:)"/>
+            <property name="severity" value="warning"/>
+        </module>
+        <module name="UpperEll"/>
+
+        <!-- https://checkstyle.org/config_filters.html#SuppressionXpathFilter -->
+        <module name="SuppressionXpathFilter">
+            <property name="file" value="${org.checkstyle.sun.suppressionxpathfilter.config}"
+                      default="checkstyle-xpath-suppressions.xml" />
+            <property name="optional" value="true"/>
+        </module>
+    </module>
+</module>