add xdg module and implement xdg data storage, default java data directory to ours, begin implementing auto-download

lsp_proxy/java.py

@@ -1,7 +1,7 @@
 import os
 import sys
 
-from .lsp import LspServer, command
+from .lsp import LspServer, command, get_data_home
 
 FILE_URI = "file://"
 
@@ -9,12 +9,14 @@ def locate_product_directory (jdt_ls_path):
     return os.path.join(jdt_ls_path, "org.eclipse.jdt.ls.product/target/repository")
 
 def locate_launcher_jar (jdt_ls_path):
-    jdt_ls_product_directory = locate_product_directory(jdt_ls_path)
-    plugins_directory = os.path.join(jdt_ls_product_directory, "plugins")
+    plugins_directory = os.path.join(jdt_ls_path, "plugins")
     return os.path.join(plugins_directory, [jar for jar in os.listdir(plugins_directory) if jar.startswith("org.eclipse.equinox.launcher_")][0])
 
 def locate_launcher_configuration (jdt_ls_path):
-    return os.path.join(locate_product_directory(jdt_ls_path), "config_linux")
+    return os.path.join(jdt_ls_path, "config_linux")
+
+def download_jdt_ls (destination):
+    raise Exception("download_jdt_ls not implemented")
 
 # TODO
 def locate_lombok ():
@@ -22,13 +24,25 @@ def locate_lombok ():
 
 class Java(LspServer):
     def __init__ (self, arguments):
-        self.path = arguments[0]
+        self.path = arguments[0] if arguments else None
+
+        if self.path is None or not os.path.exists(self.path):
+            self.path = download_jdt_ls(os.path.join(get_data_home(), "java", "jdt.ls"))
+        else:
+            self.path = locate_product_directory(self.path)
         
         command = ["java"]
         if "--enable-lombok" in arguments:
             arguments.remove("--enable-lombok")
             command.append(f"-javaagent:{locate_lombok()}")
         
+        data_directory = None
+        if "--data" in arguments:
+            data_directory = arguments.pop(arguments.index("--data") + 1)
+            arguments.remove("--data")
+        else:
+            data_directory = os.path.join(get_data_home(), "java", "data")
+
         command = command + [
             "-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=1044",
             "-Declipse.application=org.eclipse.jdt.ls.core.id1",
@@ -38,7 +52,7 @@ class Java(LspServer):
             "-Xmx1G",
             "-jar", locate_launcher_jar(self.path),
             "-configuration", locate_launcher_configuration(self.path),
-            "-data", os.path.join(self.path, "data"),
+            "-data", data_directory,
             "--add-modules=ALL-SYSTEM",
             "--add-opens", "java.base/java.util=ALL-UNNAMED",
             "--add-opens", "java.base/java.lang=ALL-UNNAMED"

lsp_proxy/lsp.py

@@ -6,6 +6,8 @@ import json
 from subprocess import run, Popen, PIPE
 from threading import Thread
 
+from xdg import xdg_data_home
+
 CONTENT_LENGTH = "Content-Length: "
 
 def process_messages (source, sink, handlers, log):
@@ -75,6 +77,12 @@ def command (name):
         return method("workspace/executeCommand")(handle_command)
     return command_handler
 
+def get_data_home ():
+    data_directory = os.path.join(xdg_data_home(), "lsp-proxy")
+    if not os.path.exists(data_directory):
+        os.makedirs(data_directory)
+    return data_directory
+
 class LspServer:
     def __init__ (self, command):
         self.command = command

setup.py

@@ -8,7 +8,7 @@ setup(
     description='lsp-proxy is a proxy for language servers.',
     author='Adrian Malacoda',
     packages=['lsp_proxy'],
-    install_requires=[],
+    install_requires=['xdg'],
     entry_points={
         'console_scripts': [
             'lsp-proxy = lsp_proxy:main'