Implement more robust way of determining binary directory

Fixes #34

VERSION.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Fixed [issue #34](https://github.com/DanielSWolf/rhubarb-lip-sync/issues/34): Generic error message in Rhubarb for Spine
 * More helpful error dialogs for internal errors in Rhubarb Lip Sync for Spine 
 * Internal errors in Rhubarb Lip Sync for Spine are logged to stderr
 

extras/EsotericSoftwareSpine/src/main/kotlin/com/rhubarb_lip_sync/rhubarb_for_spine/RhubarbTask.kt

@@ -10,8 +10,6 @@ import java.io.*
 import java.nio.charset.StandardCharsets
 import java.nio.file.Files
 import java.nio.file.Path
-import java.nio.file.Paths
-import java.time.Duration
 import java.util.concurrent.Callable
 
 class RhubarbTask(
@@ -106,12 +104,8 @@ class RhubarbTask(
 	}
 
 	private val guiBinDirectory: Path by lazy {
-		var path: String = ClassLoader.getSystemClassLoader().getResource(".")!!.path
-		if (path.length >= 3 && path[2] == ':') {
-			// Workaround for https://stackoverflow.com/questions/9834776/java-nio-file-path-issue
-			path = path.substring(1)
-		}
-		return@lazy Paths.get(path)
+		val path = urlToPath(getLocation(RhubarbTask::class.java))
+		return@lazy if (Files.isDirectory(path)) path.parent else path
 	}
 
 	private val rhubarbBinFilePath: Path by lazy {

extras/EsotericSoftwareSpine/src/main/kotlin/com/rhubarb_lip_sync/rhubarb_for_spine/classLocation.kt

@@ -0,0 +1,92 @@
+package com.rhubarb_lip_sync.rhubarb_for_spine
+
+import java.io.FileInputStream
+import java.net.MalformedURLException
+import java.net.URISyntaxException
+import java.net.URL
+import org.apache.commons.lang3.SystemUtils.IS_OS_WINDOWS
+import java.nio.file.Path
+import java.nio.file.Paths
+
+// The following code is adapted from https://stackoverflow.com/a/12733172/52041
+
+/**
+ * Gets the base location of the given class.
+ *
+ * If the class is directly on the file system (e.g.,
+ * "/path/to/my/package/MyClass.class") then it will return the base directory
+ * (e.g., "file:/path/to").
+ *
+ * If the class is within a JAR file (e.g.,
+ * "/path/to/my-jar.jar!/my/package/MyClass.class") then it will return the
+ * path to the JAR (e.g., "file:/path/to/my-jar.jar").
+ *
+ * @param c The class whose location is desired.
+ */
+fun getLocation(c: Class<*>): URL {
+	// Try the easy way first
+	try {
+		val codeSourceLocation = c.protectionDomain.codeSource.location
+		if (codeSourceLocation != null) return codeSourceLocation
+	} catch (e: SecurityException) {
+		// Cannot access protection domain
+	} catch (e: NullPointerException) {
+		// Protection domain or code source is null
+	}
+
+	// The easy way failed, so we try the hard way. We ask for the class
+	// itself as a resource, then strip the class's path from the URL string,
+	// leaving the base path.
+
+	// Get the class's raw resource path
+	val classResource = c.getResource(c.simpleName + ".class")
+		?: throw Exception("Cannot find class resource.")
+
+	val url = classResource.toString()
+	val suffix = c.canonicalName.replace('.', '/') + ".class"
+	if (!url.endsWith(suffix)) throw Exception("Malformed URL.")
+
+	// strip the class's path from the URL string
+	val base = url.substring(0, url.length - suffix.length)
+
+	var path = base
+
+	// remove the "jar:" prefix and "!/" suffix, if present
+	if (path.startsWith("jar:")) path = path.substring(4, path.length - 2)
+
+	return URL(path)
+}
+
+/**
+ * Converts the given URL to its corresponding [Path].
+ *
+ * @param url The URL to convert.
+ * @return A file path suitable for use with e.g. [FileInputStream]
+ */
+fun urlToPath(url: URL): Path {
+	var pathString = url.toString()
+
+	if (pathString.startsWith("jar:")) {
+		// Remove "jar:" prefix and "!/" suffix
+		val index = pathString.indexOf("!/")
+		pathString = pathString.substring(4, index)
+	}
+
+	try {
+		if (IS_OS_WINDOWS && pathString.matches("file:[A-Za-z]:.*".toRegex())) {
+			pathString = "file:/" + pathString.substring(5)
+		}
+		return Paths.get(URL(pathString).toURI())
+	} catch (e: MalformedURLException) {
+		// URL is not completely well-formed.
+	} catch (e: URISyntaxException) {
+		// URL is not completely well-formed.
+	}
+
+	if (pathString.startsWith("file:")) {
+		// Pass through the URL as-is, minus "file:" prefix
+		pathString = pathString.substring(5)
+		return Paths.get(pathString)
+	}
+	throw IllegalArgumentException("Invalid URL: $url")
+}