Specify Preview as entry point

So it's not marked as dead code by Intellij

idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/idea/preview/PreviewEntryPoint.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.desktop.idea.preview
+
+import com.intellij.codeInspection.reference.EntryPoint
+import com.intellij.codeInspection.reference.RefElement
+import com.intellij.configurationStore.deserializeInto
+import com.intellij.configurationStore.serializeObjectInto
+import com.intellij.openapi.util.InvalidDataException
+import com.intellij.openapi.util.WriteExternalException
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiMethod
+import org.jdom.Element
+import org.jetbrains.annotations.Nls
+
+/**
+ * [EntryPoint] implementation to mark `@Preview` functions as entry points and avoid them being flagged as unused.
+ *
+ * Based on
+ * com.android.tools.idea.compose.preview.PreviewEntryPoint from AOSP
+ * with modifications
+ */
+class PreviewEntryPoint : EntryPoint() {
+    private var ADD_PREVIEW_TO_ENTRIES: Boolean = true
+
+    override fun isEntryPoint(refElement: RefElement, psiElement: PsiElement): Boolean = isEntryPoint(psiElement)
+
+    override fun isEntryPoint(psiElement: PsiElement): Boolean =
+        psiElement is PsiMethod && psiElement.hasAnnotation(DESKTOP_PREVIEW_ANNOTATION_FQN)
+
+    override fun readExternal(element: Element) = element.deserializeInto(this)
+
+    override fun writeExternal(element: Element) {
+        serializeObjectInto(this, element)
+    }
+
+    override fun getDisplayName(): String = "Compose Preview"
+
+    override fun isSelected(): Boolean = ADD_PREVIEW_TO_ENTRIES
+
+    override fun setSelected(selected: Boolean) {
+        this.ADD_PREVIEW_TO_ENTRIES = selected
+    }
+}

idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/idea/preview/PreviewRunConfigurationProducer.kt

@@ -1,6 +1,17 @@
 /*
- * Copyright 2020-2021 JetBrains s.r.o. and respective authors and developers.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE.txt file.
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 package org.jetbrains.compose.desktop.idea.preview
@@ -22,6 +33,9 @@ import org.jetbrains.plugins.gradle.service.execution.GradleRunConfiguration
  *
  * The [ConfigurationContext] where the [ComposePreviewRunConfiguration] is created from can be any descendant of the `@Composable` function
  * in the PSI tree, such as its annotations, function name or even the keyword "fun".
+ *
+ * Based on com.android.tools.idea.compose.preview.runconfiguration.ComposePreviewRunConfigurationProducer from AOSP
+ * with modifications
  */
 class PreviewRunConfigurationProducer : LazyRunConfigurationProducer<GradleRunConfiguration>() {
     override fun getConfigurationFactory(): ConfigurationFactory =

idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/idea/preview/PreviewRunLineMarkerContributor.kt

@@ -1,6 +1,17 @@
 /*
- * Copyright 2020-2021 JetBrains s.r.o. and respective authors and developers.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE.txt file.
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 package org.jetbrains.compose.desktop.idea.preview
@@ -12,6 +23,11 @@ import com.intellij.psi.impl.source.tree.LeafPsiElement
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtNamedFunction
 
+/**
+ * Based on
+ * com.android.tools.idea.compose.preview.runconfiguration.ComposePreviewRunLineMarkerContributor from AOSP
+ * with modifications
+ */
 class PreviewRunLineMarkerContributor : RunLineMarkerContributor() {
     override fun getInfo(element: PsiElement): Info? {
         // Marker should be in a single LeafPsiElement. We choose the identifier and return null for other elements within the function.

idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/idea/preview/locationUtils.kt

@@ -1,6 +1,17 @@
 /*
- * Copyright 2020-2021 JetBrains s.r.o. and respective authors and developers.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE.txt file.
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 package org.jetbrains.compose.desktop.idea.preview
@@ -18,6 +29,11 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 internal const val DESKTOP_PREVIEW_ANNOTATION_FQN = "androidx.compose.ui.tooling.desktop.preview.Preview"
 
+/**
+ * Utils based on functions from AOSP, taken from
+ * tools/adt/idea/compose-designer/src/com/android/tools/idea/compose/preview/util/PreviewElement.kt
+ */
+
 /**
  *  Whether this function is properly annotated with [PREVIEW_ANNOTATION_FQN] and is defined in a valid location.
  *

idea-plugin/src/main/resources/META-INF/plugin.xml

@@ -15,5 +15,6 @@
                 implementationClass="org.jetbrains.compose.desktop.idea.preview.PreviewRunLineMarkerContributor"/>
         <runConfigurationProducer
                 implementation="org.jetbrains.compose.desktop.idea.preview.PreviewRunConfigurationProducer"/>
+        <deadCode implementation="org.jetbrains.compose.desktop.idea.preview.PreviewEntryPoint" />
     </extensions>
 </idea-plugin>

license/README.md

@@ -4,13 +4,9 @@ to which different licenses may apply:
 
 ## Compose IDEA plugin
 
-* Path: idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/idea/preview/PreviewRunLineMarkerContributor.kt
-    * License: Apache 2 (license/third_party/aosp_license.txt)
-    * Origin: Copyright 2021 The Android Open Source Project
-* Path: idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/idea/preview/locationUtils.kt
-    * License: Apache 2 (license/third_party/aosp_license.txt)
-    * Origin: Copyright 2021 The Android Open Source Project
+* Path: idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/idea/preview
+  * License: Apache 2 (license/third_party/aosp_license.txt)
+  * Origin: Copyright 2021 The Android Open Source Project
 * Path: idea-plugin/src/main/resources/icons/compose/compose.svg
     * License: Apache 2 (license/third_party/aosp_license.txt)
     * Origin: Copyright 2021 The Android Open Source Project
-