[android] using @Keep annotation across the project with the help of lint checks

5 files changed, 150 insertions, 0 deletions

diff --git a/platform/android/MapboxGLAndroidSDKLint/.gitignore b/platform/android/MapboxGLAndroidSDKLint/.gitignore
new file mode 100644
index 0000000000..796b96d1c4
--- /dev/null
+++ b/platform/android/MapboxGLAndroidSDKLint/.gitignore
@@ -0,0 +1 @@
+/build
diff --git a/platform/android/MapboxGLAndroidSDKLint/build.gradle b/platform/android/MapboxGLAndroidSDKLint/build.gradle
new file mode 100644
index 0000000000..855e1bc7ca
--- /dev/null
+++ b/platform/android/MapboxGLAndroidSDKLint/build.gradle
@@ -0,0 +1,37 @@
+apply plugin: 'java-library'
+apply plugin: 'kotlin'
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    compileOnly dependenciesList.kotlinLib
+
+    compileOnly dependenciesList.lint
+    compileOnly dependenciesList.lintApi
+    compileOnly dependenciesList.lintChecks
+    compileOnly dependenciesList.supportAnnotations
+
+    testImplementation dependenciesList.junit
+    testImplementation dependenciesList.robolectric
+    testImplementation dependenciesList.lintTests
+}
+
+sourceCompatibility = "1.8"
+targetCompatibility = "1.8"
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+jar {
+    manifest {
+        attributes("Lint-Registry-v2": "com.mapbox.mapboxsdk.lint.MapboxIssueRegistry")
+    }
+}
diff --git a/platform/android/MapboxGLAndroidSDKLint/src/main/java/com/mapbox/mapboxsdk/lint/KeepDetector.kt b/platform/android/MapboxGLAndroidSDKLint/src/main/java/com/mapbox/mapboxsdk/lint/KeepDetector.kt
new file mode 100644
index 0000000000..64838f91db
--- /dev/null
+++ b/platform/android/MapboxGLAndroidSDKLint/src/main/java/com/mapbox/mapboxsdk/lint/KeepDetector.kt
@@ -0,0 +1,75 @@
+package com.mapbox.mapboxsdk.lint
+
+import com.android.tools.lint.client.api.UElementHandler
+import com.android.tools.lint.detector.api.*
+import com.intellij.lang.jvm.JvmModifier
+import com.intellij.psi.PsiType
+import org.jetbrains.uast.*
+
+class KeepDetector : Detector(), SourceCodeScanner, FileScanner {
+  companion object {
+    private val DETECTOR_CLASS = KeepDetector::class.java
+    private val DETECTOR_SCOPE = Scope.JAVA_FILE_SCOPE
+    private val IMPLEMENTATION = Implementation(DETECTOR_CLASS, DETECTOR_SCOPE)
+
+    private const val ISSUE_ID = "KeepMissing"
+    private const val ISSUE_DESCRIPTION = "Element cannot be minified."
+    private const val ISSUE_EXPLANATION = "This class, method or field might contain native references. " +
+      "It has to be annotated with @Keep if it cannot be obfuscated/removed, otherwise, the warning should be suppressed. " +
+      "There can also be another methods/fields of this class that cannot be obfuscated/removed, " +
+      "look closely for any methods that are referenced from the JNI context."
+    private val ISSUE_CATEGORY = Category.CORRECTNESS
+    private const val ISSUE_PRIORITY = 9
+    private val ISSUE_SEVERITY = Severity.ERROR
+
+    var ISSUE_NOT_KEPT = Issue.create(
+      ISSUE_ID,
+      ISSUE_DESCRIPTION,
+      ISSUE_EXPLANATION,
+      ISSUE_CATEGORY,
+      ISSUE_PRIORITY,
+      ISSUE_SEVERITY,
+      IMPLEMENTATION
+    )
+  }
+
+  override fun getApplicableUastTypes(): List<Class<out UElement>>? =
+    listOf(UMethod::class.java, UField::class.java)
+
+  override fun createUastHandler(context: JavaContext): UElementHandler? = KeepHandler(context)
+
+  class KeepHandler(private val context: JavaContext) : UElementHandler() {
+
+    override fun visitMethod(node: UMethod) {
+      if (node.hasModifier(JvmModifier.NATIVE) && checkKeepAnnotation(node)) {
+        context.report(ISSUE_NOT_KEPT, node,
+          context.getNameLocation(node),
+          "This method contains native references and will be minified.")
+      } else if (node.isConstructor
+        && node.parameterList.parameters.find { it.type == PsiType.LONG && it.name!!.contains("native") } != null
+        && checkKeepAnnotation(node)) {
+        context.report(ISSUE_NOT_KEPT, node,
+          context.getNameLocation(node as UElement),
+          "This constructor might contain native references and will be minified. " +
+            "Either suppress the warning or use @Keep.")
+      }
+    }
+
+    override fun visitField(node: UField) {
+      if (node.type == PsiType.LONG && node.name.contains("native") && checkKeepAnnotation(node)) {
+        context.report(ISSUE_NOT_KEPT, node,
+          context.getNameLocation(node as UElement),
+          "This field might contain native references and will be minified. " +
+            "Either suppress the warning or use @Keep.")
+      }
+    }
+
+    private fun checkKeepAnnotation(uAnnotated: UAnnotated): Boolean {
+      return !hasKeepAnnotation(uAnnotated) && !hasKeepAnnotation(uAnnotated.getContainingUClass()!!)
+    }
+
+    private fun hasKeepAnnotation(uAnnotated: UAnnotated): Boolean {
+      return uAnnotated.findAnnotation("android.support.annotation.Keep") != null
+    }
+  }
+}
\ No newline at end of file
diff --git a/platform/android/MapboxGLAndroidSDKLint/src/main/java/com/mapbox/mapboxsdk/lint/MapboxIssueRegistry.kt b/platform/android/MapboxGLAndroidSDKLint/src/main/java/com/mapbox/mapboxsdk/lint/MapboxIssueRegistry.kt
new file mode 100644
index 0000000000..790fab99ea
--- /dev/null
+++ b/platform/android/MapboxGLAndroidSDKLint/src/main/java/com/mapbox/mapboxsdk/lint/MapboxIssueRegistry.kt
@@ -0,0 +1,9 @@
+package com.mapbox.mapboxsdk.lint
+
+import com.android.tools.lint.client.api.IssueRegistry
+import com.android.tools.lint.detector.api.Issue
+
+class MapboxIssueRegistry : IssueRegistry() {
+  override val issues: List<Issue>
+    get() = listOf(KeepDetector.ISSUE_NOT_KEPT)
+}
\ No newline at end of file
diff --git a/platform/android/MapboxGLAndroidSDKLint/src/test/java/com/mapbox/mapboxsdk/lint/KeepDetectorTest.kt b/platform/android/MapboxGLAndroidSDKLint/src/test/java/com/mapbox/mapboxsdk/lint/KeepDetectorTest.kt
new file mode 100644
index 0000000000..491769df93
--- /dev/null
+++ b/platform/android/MapboxGLAndroidSDKLint/src/test/java/com/mapbox/mapboxsdk/lint/KeepDetectorTest.kt
@@ -0,0 +1,28 @@
+package com.mapbox.mapboxsdk.lint
+
+import com.android.tools.lint.checks.infrastructure.TestFiles.java
+import com.android.tools.lint.checks.infrastructure.TestLintTask.lint
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+
+@RunWith(RobolectricTestRunner::class)
+class KeepDetectorTest {
+
+  @Test
+  fun correctClassName() {
+    lint()
+      .allowMissingSdk()
+      .files(java("""
+        |package foo;
+        |
+        |import android.support.annotation.Keep;
+        |
+        |@Keep
+        |class TestClass {
+        |}""".trimMargin()))
+      .issues(KeepDetector.ISSUE_NOT_KEPT)
+      .run()
+      .expectClean()
+  }
+}
\ No newline at end of file