Merge branch 'javainfo' into master

picomc/config.py

@@ -6,9 +6,21 @@
 from picomc.utils import cached_property
 
 
+def get_default_java():
+    java_home = os.getenv("JAVA_HOME")
+    if java_home is not None:
+        candidates = ["java", "java.exe"]
+        for candidate in candidates:
+            path = os.path.join(java_home, "bin", candidate)
+            if os.path.isfile(path):
+                logger.debug("Detected JAVA_HOME, using as default")
+                return path
+    return "java"
+
+
 def get_default_config():
     return {
-        "java.path": "java",
+        "java.path": get_default_java(),
         "java.memory.min": "512M",
         "java.memory.max": "2G",
         "java.jvmargs": "-XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M",

picomc/instance.py

@@ -12,7 +12,7 @@
 
 import picomc
 from picomc import logging
-from picomc.javainfo import assert_java
+from picomc.java import assert_java
 from picomc.logging import logger
 from picomc.rules import match_ruleset
 from picomc.utils import Directory, join_classpath, sanitize_name

picomc/java/__init__.py

@@ -0,0 +1 @@
+from .javainfo import assert_java, get_java_info

picomc/java/javainfo.py

@@ -0,0 +1,78 @@
+import os
+import shutil
+import subprocess
+from importlib import resources
+from tempfile import TemporaryDirectory
+
+from picomc.logging import logger
+from picomc.utils import die
+
+#
+# SysDump.class:
+#
+# import java.io.IOException;
+#
+# public class SysDump {
+#   public static void main(String[] args) throws IOException {
+#     System.getProperties().storeToXML(System.out, "");
+#   }
+# }
+#
+# Compiled with an antique version of java for widest compatibility.
+# Ideally we would distribute the source .java file and build it in the
+# picomc build process, but that would bring in a dependency for (old) java
+# and extra complexity.
+#
+
+
+def get_java_info(java):
+    with TemporaryDirectory() as tmpdir:
+        with resources.open_binary("picomc.java", "SysDump.class") as incf, open(
+            os.path.join(tmpdir, "SysDump.class"), "wb"
+        ) as outcf:
+            shutil.copyfileobj(incf, outcf)
+        ret = subprocess.run(
+            [java, "-cp", ".", "SysDump"], cwd=tmpdir, capture_output=True
+        )
+    from xml.etree import ElementTree
+
+    xmlstr = ret.stdout.decode("utf8")
+    props = ElementTree.fromstring(xmlstr)
+    res = dict()
+    for entry in props:
+        if "entry" != entry.tag or "key" not in entry.attrib:
+            continue
+        res[entry.attrib["key"]] = entry.text
+    return res
+
+
+def assert_java(java):
+    try:
+        jinfo = get_java_info(java)
+        badjv = not jinfo["java.version"].startswith("1.8.0")
+        bitness = jinfo.get("sun.arch.data.model", None)
+        if bitness and bitness != "64":
+            logger.warning(
+                "You are not using 64-bit java. Things will probably not work."
+            )
+
+        logger.info(
+            "Using java version: {} ({})".format(
+                jinfo["java.version"], jinfo["java.vm.name"]
+            )
+        )
+
+        if badjv:
+            logger.warning(
+                "Minecraft uses java 1.8.0 by default."
+                " You may experience issues, especially with older versions of Minecraft."
+            )
+
+        return jinfo
+
+    except FileNotFoundError:
+        die(
+            "Could not execute java at: {}. Have you installed it? Is it in yout PATH?".format(
+                java
+            )
+        )

picomc/osinfo.py

@@ -32,7 +32,7 @@ def get_arch():
     def get_os_version(java_info):
         if not java_info:
             return None, None
-        version = java_info.get("os.version").decode("ascii")
+        version = java_info.get("os.version")
         return version
 
 

picomc/version.py

@@ -12,7 +12,7 @@
 import requests
 
 from picomc.downloader import DownloadQueue
-from picomc.javainfo import get_java_info
+from picomc.java import get_java_info
 from picomc.library import Library
 from picomc.logging import logger
 from picomc.rules import match_ruleset

setup.py

@@ -31,4 +31,5 @@
     ],
     python_requires=">=3.7",
     entry_points={"console_scripts": ["picomc = picomc:main"]},
+    package_data={"picomc.java": ["SysDump.class"]},
 )