File associations (#4957)

Add file associations support to Compose Desktop

<!-- Optional -->
Fixes #773

## Testing

Tested on the [sample
project](https://github.com/zhelenskiy/file-associations-demo).
Behaviours per OSs:
- MacOS Sonoma: associations work for distributables.
- Windows 11: associations work after the installation of the MSI.
- Kubuntu: associations do not work, but everything else works fine.
However, IDEA also does not have associations there, so I assume this is
fine.

I didn't write any unit tests because I don’t know which of them you are
expecting me to write. So, I'm looking forward to your feedback and
suggestions.

<!-- Optional -->
This should be tested by QA

## Release Notes
<!--
Optional, if omitted - won't be included in the changelog

Sections:
- Highlights
- Known issues
- Breaking changes
- Features
- Fixes

Subsections:
- Multiple Platforms
- iOS
- Desktop
- Web
- Resources
- Gradle Plugin
-->
### Highlight - Desktop
- Introduction of the new DSL function in `nativeDistributions` block:
  ```kotlin
fun fileAssociation(mimeType: String, extension: String, description:
String): Unit
  ```

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/desktop/application/dsl/FileAssociation.kt

@@ -0,0 +1,11 @@
+package org.jetbrains.compose.desktop.application.dsl
+
+import java.io.File
+import java.io.Serializable
+
+internal data class FileAssociation(
+    val mimeType: String,
+    val extension: String,
+    val description: String,
+    val iconFile: File?,
+) : Serializable

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/desktop/application/dsl/JvmApplicationDistributions.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.compose.desktop.application.dsl
 
 import org.gradle.api.Action
+import java.io.File
 
 internal val DEFAULT_RUNTIME_MODULES = arrayOf(
     "java.base", "java.desktop", "java.logging", "jdk.crypto.ec"
@@ -32,4 +33,14 @@ abstract class JvmApplicationDistributions : AbstractDistributions() {
     fun windows(fn: Action<WindowsPlatformSettings>) {
         fn.execute(windows)
     }
+
+    @JvmOverloads
+    fun fileAssociation(
+        mimeType: String, extension: String, description: String,
+        linuxIconFile: File? = null, windowsIconFile: File? = null, macOSIconFile: File? = null,
+    ) {
+        linux.fileAssociation(mimeType, extension, description, linuxIconFile)
+        windows.fileAssociation(mimeType, extension, description, windowsIconFile)
+        macOS.fileAssociation(mimeType, extension, description, macOSIconFile)
+    }
 }

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/desktop/application/dsl/PlatformSettings.kt

@@ -8,6 +8,7 @@ package org.jetbrains.compose.desktop.application.dsl
 import org.gradle.api.Action
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.model.ObjectFactory
+import java.io.File
 import javax.inject.Inject
 
 abstract class AbstractPlatformSettings {
@@ -17,6 +18,13 @@ abstract class AbstractPlatformSettings {
     val iconFile: RegularFileProperty = objects.fileProperty()
     var packageVersion: String? = null
     var installationPath: String? = null
+
+    internal val fileAssociations: MutableSet<FileAssociation> = mutableSetOf()
+
+    @JvmOverloads
+    fun fileAssociation(mimeType: String, extension: String, description: String, iconFile: File? = null) {
+        fileAssociations.add(FileAssociation(mimeType, extension, description, iconFile))
+    }
 }
 
 abstract class AbstractMacOSPlatformSettings : AbstractPlatformSettings() {

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/desktop/application/internal/InfoPlistBuilder.kt

@@ -5,14 +5,58 @@
 
 package org.jetbrains.compose.desktop.application.internal
 
+import org.jetbrains.compose.desktop.application.internal.InfoPlistBuilder.InfoPlistValue.*
 import java.io.File
 import kotlin.reflect.KProperty
 
+private const val indent = "  "
+private fun indentForLevel(level: Int) = indent.repeat(level)
+
 internal class InfoPlistBuilder(private val extraPlistKeysRawXml: String? = null) {
-    private val values = LinkedHashMap<InfoPlistKey, String>()
+    internal sealed class InfoPlistValue {
+        abstract fun asPlistEntry(nestingLevel: Int): String
+        data class InfoPlistListValue(val elements: List<InfoPlistValue>) : InfoPlistValue() {
+            override fun asPlistEntry(nestingLevel: Int): String =
+                if (elements.isEmpty()) "${indentForLevel(nestingLevel)}<array/>"
+                else elements.joinToString(
+                    separator = "\n",
+                    prefix = "${indentForLevel(nestingLevel)}<array>\n",
+                    postfix = "\n${indentForLevel(nestingLevel)}</array>"
+                ) {
+                    it.asPlistEntry(nestingLevel + 1)
+                }
+
+            constructor(vararg elements: InfoPlistValue) : this(elements.asList())
+        }
+
+        data class InfoPlistMapValue(val elements: Map<InfoPlistKey, InfoPlistValue>) : InfoPlistValue() {
+            override fun asPlistEntry(nestingLevel: Int): String =
+                if (elements.isEmpty()) "${indentForLevel(nestingLevel)}<dict/>"
+                else elements.entries.joinToString(
+                    separator = "\n",
+                    prefix = "${indentForLevel(nestingLevel)}<dict>\n",
+                    postfix = "\n${indentForLevel(nestingLevel)}</dict>",
+                ) { (key, value) ->
+                    "${indentForLevel(nestingLevel + 1)}<key>${key.name}</key>\n${value.asPlistEntry(nestingLevel + 1)}"
+                }
+
+            constructor(vararg elements: Pair<InfoPlistKey, InfoPlistValue>) : this(elements.toMap())
+        }
+
+        data class InfoPlistStringValue(val value: String) : InfoPlistValue() {
+            override fun asPlistEntry(nestingLevel: Int): String = if (value.isEmpty()) "${indentForLevel(nestingLevel)}<string/>" else "${indentForLevel(nestingLevel)}<string>$value</string>"
+        }
+    }
+
+    private val values = LinkedHashMap<InfoPlistKey, InfoPlistValue>()
+
+    operator fun get(key: InfoPlistKey): InfoPlistValue? = values[key]
+    operator fun set(key: InfoPlistKey, value: String?) = set(key, value?.let(::InfoPlistStringValue))
+    operator fun set(key: InfoPlistKey, value: List<InfoPlistValue>?) = set(key, value?.let(::InfoPlistListValue))
+    operator fun set(key: InfoPlistKey, value: Map<InfoPlistKey, InfoPlistValue>?) =
+        set(key, value?.let(::InfoPlistMapValue))
 
-    operator fun get(key: InfoPlistKey): String? = values[key]
-    operator fun set(key: InfoPlistKey, value: String?) {
+    operator fun set(key: InfoPlistKey, value: InfoPlistValue?) {
         if (value != null) {
             values[key] = value
         } else {
@@ -26,13 +70,13 @@ internal class InfoPlistBuilder(private val extraPlistKeysRawXml: String? = null
                 appendLine("<?xml version=\"1.0\" ?>")
                 appendLine("<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" \"https://www.apple.com/DTDs/PropertyList-1.0.dtd\">")
                 appendLine("<plist version=\"1.0\">")
-                appendLine(" <dict>")
+                appendLine("${indentForLevel(1)}<dict>")
                 for ((k, v) in values) {
-                    appendLine("  <key>${k.name}</key>")
-                    appendLine("  <string>$v</string>")
+                    appendLine("${indentForLevel(2)}<key>${k.name}</key>")
+                    appendLine(v.asPlistEntry(2))
                 }
                 extraPlistKeysRawXml?.let { appendLine(it) }
-                appendLine(" </dict>")
+                appendLine("${indentForLevel(1)}</dict>")
                 appendLine("</plist>")
             }
         }
@@ -48,6 +92,13 @@ internal object PlistKeys {
     val LSMinimumSystemVersion by this
     val CFBundleDevelopmentRegion by this
     val CFBundleAllowMixedLocalizations by this
+    val CFBundleDocumentTypes by this
+    val CFBundleTypeRole by this
+    val CFBundleTypeExtensions by this
+    val CFBundleTypeIconFile by this
+    val CFBundleTypeMIMETypes by this
+    val CFBundleTypeName by this
+    val CFBundleTypeOSTypes by this
     val CFBundleExecutable by this
     val CFBundleIconFile by this
     val CFBundleIdentifier by this

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/desktop/application/internal/configureJvmApplication.kt

@@ -375,6 +375,7 @@ internal fun JvmApplicationContext.configurePlatformSettings(
                 packageTask.linuxRpmLicenseType.set(provider { linux.rpmLicenseType })
                 packageTask.iconFile.set(linux.iconFile.orElse(defaultResources.get { linuxIcon }))
                 packageTask.installationPath.set(linux.installationPath)
+                packageTask.fileAssociations.set(provider { linux.fileAssociations })
             }
         }
         OS.Windows -> {
@@ -388,6 +389,7 @@ internal fun JvmApplicationContext.configurePlatformSettings(
                 packageTask.winUpgradeUuid.set(provider { win.upgradeUuid })
                 packageTask.iconFile.set(win.iconFile.orElse(defaultResources.get { windowsIcon }))
                 packageTask.installationPath.set(win.installationPath)
+                packageTask.fileAssociations.set(provider { win.fileAssociations })
             }
         }
         OS.MacOS -> {
@@ -414,6 +416,7 @@ internal fun JvmApplicationContext.configurePlatformSettings(
                 packageTask.nonValidatedMacSigningSettings = app.nativeDistributions.macOS.signing
                 packageTask.iconFile.set(mac.iconFile.orElse(defaultResources.get { macIcon }))
                 packageTask.installationPath.set(mac.installationPath)
+                packageTask.fileAssociations.set(provider { mac.fileAssociations })
             }
         }
     }

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/desktop/application/tasks/AbstractJPackageTask.kt

@@ -9,19 +9,23 @@ import org.gradle.api.file.*
 import org.gradle.api.provider.ListProperty
 import org.gradle.api.provider.Property
 import org.gradle.api.provider.Provider
+import org.gradle.api.provider.SetProperty
 import org.gradle.api.tasks.*
 import org.gradle.api.tasks.Optional
 import org.gradle.process.ExecResult
 import org.gradle.work.ChangeType
 import org.gradle.work.InputChanges
+import org.jetbrains.compose.desktop.application.dsl.FileAssociation
 import org.jetbrains.compose.desktop.application.dsl.MacOSSigningSettings
 import org.jetbrains.compose.desktop.application.dsl.TargetFormat
 import org.jetbrains.compose.desktop.application.internal.*
+import org.jetbrains.compose.desktop.application.internal.InfoPlistBuilder.InfoPlistValue.*
 import org.jetbrains.compose.desktop.application.internal.files.*
 import org.jetbrains.compose.desktop.application.internal.files.MacJarSignFileCopyingProcessor
 import org.jetbrains.compose.desktop.application.internal.JvmRuntimeProperties
 import org.jetbrains.compose.desktop.application.internal.validation.validate
 import org.jetbrains.compose.internal.utils.*
+import org.jetbrains.kotlin.gradle.internal.ensureParentDirsCreated
 import java.io.*
 import java.nio.file.LinkOption
 import java.util.*
@@ -244,6 +248,39 @@ abstract class AbstractJPackageTask @Inject constructor(
     @get:Optional
     val javaRuntimePropertiesFile: RegularFileProperty = objects.fileProperty()
 
+    @get:Input
+    internal val fileAssociations: SetProperty<FileAssociation> = objects.setProperty(FileAssociation::class.java)
+
+    private val iconMapping by lazy {
+        val icons = fileAssociations.get().mapNotNull { it.iconFile }.distinct()
+        if (icons.isEmpty()) return@lazy emptyMap()
+        val iconTempNames: List<String> = mutableListOf<String>().apply {
+            val usedNames = mutableSetOf("${packageName.get()}.icns")
+            for (icon in icons) {
+                if (!icon.exists()) continue
+                if (usedNames.add(icon.name)) {
+                    add(icon.name)
+                    continue
+                }
+                val nameWithoutExtension = icon.nameWithoutExtension
+                val extension = icon.extension
+                for (n in 1UL..ULong.MAX_VALUE) {
+                    val newName = "$nameWithoutExtension ($n).$extension"
+                    if (usedNames.add(newName)) {
+                        add(newName)
+                        break
+                    }
+                }
+            }
+        }
+        val appDir = destinationDir.ioFile.resolve("${packageName.get()}.app")
+        val iconsDir = appDir.resolve("Contents").resolve("Resources")
+        if (iconsDir.exists()) {
+            iconsDir.deleteRecursively()
+        }
+        icons.zip(iconTempNames) { icon, newName -> icon to iconsDir.resolve(newName) }.toMap()
+    }
+
     private lateinit var jvmRuntimeInfo: JvmRuntimeProperties
 
     @get:Optional
@@ -273,6 +310,9 @@ abstract class AbstractJPackageTask @Inject constructor(
     @get:LocalState
     protected val skikoDir: Provider<Directory> = project.layout.buildDirectory.dir("compose/tmp/skiko")
 
+    @get:LocalState
+    protected val propertyFilesDir: Provider<Directory> = project.layout.buildDirectory.dir("compose/tmp/propertyFiles")
+
     @get:Internal
     private val libsDir: Provider<Directory> = workingDir.map {
         it.dir("libs")
@@ -368,6 +408,33 @@ abstract class AbstractJPackageTask @Inject constructor(
             cliArg("--license-file", licenseFile)
             cliArg("--resource-dir", jpackageResources)
 
+            val propertyFilesDirJava = propertyFilesDir.ioFile
+            fileOperations.clearDirs(propertyFilesDir)
+
+            val fileAssociationFiles = fileAssociations.get()
+                .groupBy { it.extension }
+                .mapValues { (extension, associations) ->
+                    associations.mapIndexed { index, association ->
+                        propertyFilesDirJava.resolve("FA${extension}${if (index > 0) index.toString() else ""}.properties")
+                            .apply {
+                                val withoutIcon = """
+                                    mime-type=${association.mimeType}
+                                    extension=${association.extension}
+                                    description=${association.description}
+                                """.trimIndent()
+                                writeText(
+                                    if (association.iconFile == null) withoutIcon
+                                    else "${withoutIcon}\nicon=${association.iconFile.normalizedPath()}"
+                                )
+                            }
+                    }
+                }.values.flatten()
+
+            for (fileAssociationFile in fileAssociationFiles) {
+                cliArg("--file-associations", fileAssociationFile)
+            }
+
+
             when (currentOS) {
                 OS.Linux -> {
                     cliArg("--linux-shortcut", linuxShortcut)
@@ -569,6 +636,15 @@ abstract class AbstractJPackageTask @Inject constructor(
 
         macSigner.sign(runtimeDir, runtimeEntitlementsFile, forceEntitlements = true)
         macSigner.sign(appDir, appEntitlementsFile, forceEntitlements = true)
+
+        if (iconMapping.isNotEmpty()) {
+            for ((originalIcon, newIcon) in iconMapping) {
+                if (originalIcon.exists()) {
+                    newIcon.ensureParentDirsCreated()
+                    originalIcon.copyTo(newIcon)
+                }
+            }
+        }
     }
 
     override fun initState() {
@@ -620,6 +696,23 @@ abstract class AbstractJPackageTask @Inject constructor(
             ?: "Copyright (C) $year"
         plist[PlistKeys.NSSupportsAutomaticGraphicsSwitching] = "true"
         plist[PlistKeys.NSHighResolutionCapable] = "true"
+        val fileAssociationMutableSet = fileAssociations.get()
+        if (fileAssociationMutableSet.isNotEmpty()) {
+            plist[PlistKeys.CFBundleDocumentTypes] = fileAssociationMutableSet
+                .groupBy { it.mimeType to it.description }
+                .map { (key, extensions) ->
+                    val (mimeType, description) = key
+                    val iconPath = extensions.firstNotNullOfOrNull { it.iconFile }?.let { iconMapping[it]?.name }
+                    InfoPlistMapValue(
+                        PlistKeys.CFBundleTypeRole to InfoPlistStringValue("Editor"),
+                        PlistKeys.CFBundleTypeExtensions to InfoPlistListValue(extensions.map { InfoPlistStringValue(it.extension) }),
+                        PlistKeys.CFBundleTypeIconFile to InfoPlistStringValue(iconPath ?: "$packageName.icns"),
+                        PlistKeys.CFBundleTypeMIMETypes to InfoPlistStringValue(mimeType),
+                        PlistKeys.CFBundleTypeName to InfoPlistStringValue(description),
+                        PlistKeys.CFBundleTypeOSTypes to InfoPlistListValue(InfoPlistStringValue("****")),
+                    )
+                }
+        }
     }
 }