Add support for Kotlin installed by Scoop

Author: tats-u

shared/src/main/kotlin/org/javacs/kt/classpath/BackupClassPathResolver.kt

@@ -8,6 +8,7 @@ import java.util.function.BiPredicate
 import org.javacs.kt.util.tryResolving
 import org.javacs.kt.util.findCommandOnPath
 import org.javacs.kt.LOG
+import org.javacs.kt.util.OSContext
 import java.nio.file.Paths
 
 /** Backup classpath that find Kotlin in the user's Maven/Gradle home or kotlinc's libraries folder. */
@@ -78,7 +79,7 @@ private fun findKotlinCliCompilerLibrary(name: String): Path? =
 // alternative library locations like for snap
 // (can probably just use elvis operator and multiple similar expressions for other install directories)
 private fun findAlternativeLibraryLocation(name: String): Path? =
-    Paths.get("/snap/kotlin/current/lib/${name}.jar").existsOrNull()
+    Paths.get(OSContext.CURRENT_OS.findAlternativeLibraryLocation(name)).existsOrNull()
 
 private fun Path.existsOrNull() =
     if (Files.exists(this)) this else null

shared/src/main/kotlin/org/javacs/kt/util/OSContext.kt

@@ -0,0 +1,27 @@
+package org.javacs.kt.util
+
+/**
+ * Tasks that depends on user's OS
+ */
+interface OSContext {
+    /**
+     * Resolves the locations of the given JAR
+     *
+     * @param name the name of the JAR
+     * @return the full path to the JAR
+     */
+    fun findAlternativeLibraryLocation(name: String): String
+    companion object {
+        /**
+         * Gets the instance for the current OS
+         */
+        @JvmStatic
+        val CURRENT_OS by lazy<OSContext> {
+            val osName = System.getProperty("os.name")!!.lowercase()
+            when {
+                osName.contains("windows") -> WindowsContext()
+                else -> UnixContext()
+            }
+        }
+    }
+}

shared/src/main/kotlin/org/javacs/kt/util/UnixContext.kt

@@ -0,0 +1,9 @@
+package org.javacs.kt.util
+
+/**
+ * Tasks for other than Windows
+ */
+class UnixContext : OSContext {
+    override fun findAlternativeLibraryLocation(name: String): String = // Snap (Linux)
+        "/snap/kotlin/current/lib/${name}.jar"
+}

shared/src/main/kotlin/org/javacs/kt/util/WindowsContext.kt

@@ -0,0 +1,13 @@
+package org.javacs.kt.util
+
+/**
+ * Tasks only for Windows
+ */
+class WindowsContext : OSContext {
+    /**
+     * Absolute path to the user's profile folder (home directory)
+     */
+    private val userProfile = System.getenv("USERPROFILE")
+    override fun findAlternativeLibraryLocation(name: String): String = // Scoop (https://scoop.sh)
+        "${userProfile}\\scoop\\apps\\kotlin\\current\\lib\\\${name}.jar"
+}