Remove src.zip and get it from JAVA_HOME

What
===
Remove src.zip and get it from the path pointed to by the JAVA_HOME
environment variable.

Why
===
When using this tool standalone the lib/src.zip file doesn't seem to be
packaged inside what is jlinked which causes exceptions on startup. It
also seems odd to package src.zip inside the tool when Java JDK
installations come with src, and in the event they don't (e.g.  OpenJDK
on Debian) they can be easily installed using the distros built in
package manager.

As a side note the src.zip licensing is ambiguous to me and it's not
clear from any other documentation in this repository how it is being
licensed. I assume it is properly licensed to have been included, but
regardless removing any licensing ambiguity from the tool seems ideal
for those using it.

4 files changed, 24 insertions, 12 deletions

diff --git a/javaLsFlag.txt b/javaLsFlag.txt
deleted file mode 100644
index 4babb58..0000000
--- a/javaLsFlag.txt
+++ /dev/null
@@ -1 +0,0 @@
-This file is a flag to help Lib#installRoot find the root directory of the extension.
\ No newline at end of file
diff --git a/lib/src.zip b/lib/src.zip
deleted file mode 100644
index d08e5b4..0000000
--- a/lib/src.zip
+++ /dev/null
diff --git a/src/main/java/org/javacs/Docs.java b/src/main/java/org/javacs/Docs.java
index 586d3f9..1920fb7 100644
--- a/src/main/java/org/javacs/Docs.java
+++ b/src/main/java/org/javacs/Docs.java
@@ -15,10 +15,13 @@ public class Docs {
     /** File manager with source-path + platform sources, which we will use to look up individual source files */
     private final SourceFileManager fileManager = new SourceFileManager();
 
-    private static Path srcZip() {
+    private static Optional<Path> srcZip() {
+        if (!Lib.SRC_ZIP.isPresent()) {
+            return Optional.empty();
+        }
         try {
-            var fs = FileSystems.newFileSystem(Lib.SRC_ZIP, Docs.class.getClassLoader());
-            return fs.getPath("/");
+            var fs = FileSystems.newFileSystem(Lib.SRC_ZIP.get(), Docs.class.getClassLoader());
+            return Optional.of(fs.getPath("/"));
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
@@ -30,7 +33,10 @@ public class Docs {
 
         try {
             fileManager.setLocation(StandardLocation.SOURCE_PATH, sourcePathFiles);
-            fileManager.setLocationFromPaths(StandardLocation.MODULE_SOURCE_PATH, Set.of(srcZip()));
+            Optional<Path> srcZipPath = srcZip();
+            if (srcZipPath.isPresent()) {
+                fileManager.setLocationFromPaths(StandardLocation.MODULE_SOURCE_PATH, Set.of(srcZipPath.get()));
+            }
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
diff --git a/src/main/java/org/javacs/Lib.java b/src/main/java/org/javacs/Lib.java
index 924f98c..61c5bc4 100644
--- a/src/main/java/org/javacs/Lib.java
+++ b/src/main/java/org/javacs/Lib.java
@@ -1,15 +1,22 @@
 package org.javacs;
 
+import java.io.File;
+import java.lang.System;
+import java.util.Optional;
 import java.nio.file.*;
 
 class Lib {
-    static Path installRoot() {
-        var root = Paths.get(".").toAbsolutePath();
-        var p = root;
-        while (p != null && !Files.exists(p.resolve("javaLsFlag.txt"))) p = p.getParent();
-        if (p == null) throw new RuntimeException("Couldn't find javaLsFlag.txt in any parent of " + root);
-        return p;
+    static Optional<Path> srcZipPath() {
+        return Optional.ofNullable(System.getenv("JAVA_HOME"))
+            .flatMap(home -> Optional.of(Paths.get(home).resolve("lib/src.zip")))
+            .flatMap(path -> {
+                if (path.toFile().exists()) {
+                    return Optional.of(path);
+                } else {
+                    return Optional.empty();
+                }
+            });
     }
 
-    static final Path SRC_ZIP = installRoot().resolve("lib/src.zip");
+    static final Optional<Path> SRC_ZIP = srcZipPath();
 }