Dissolve gerrit-pgm top-level directory

Change-Id: Ia03015b91da3df4a8672bc30f13b3e3f048a628c

java/com/google/gerrit/pgm/JythonShell.java

@@ -0,0 +1,231 @@
+// Copyright (C) 2013 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.pgm;
+
+import com.google.gerrit.launcher.GerritLauncher;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.Properties;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class JythonShell {
+  private static final Logger log = LoggerFactory.getLogger(JythonShell.class);
+  private static final String STARTUP_RESOURCE = "com/google/gerrit/pgm/Startup.py";
+  private static final String STARTUP_FILE = "Startup.py";
+
+  private Class<?> console;
+  private Class<?> pyObject;
+  private Class<?> pySystemState;
+  private Object shell;
+  private ArrayList<String> injectedVariables;
+
+  public JythonShell() {
+    Properties env = new Properties();
+    // Let us inspect private class members
+    env.setProperty("python.security.respectJavaAccessibility", "false");
+
+    File home = GerritLauncher.getHomeDirectory();
+    if (home != null) {
+      env.setProperty("python.cachedir", new File(home, "jythoncache").getPath());
+    }
+
+    // For package introspection and "import com.google" to work,
+    // Jython needs to inspect actual .jar files (not just classloader)
+    StringBuilder classPath = new StringBuilder();
+    final ClassLoader cl = getClass().getClassLoader();
+    if (cl instanceof java.net.URLClassLoader) {
+      @SuppressWarnings("resource")
+      URLClassLoader ucl = (URLClassLoader) cl;
+      for (URL u : ucl.getURLs()) {
+        if ("file".equals(u.getProtocol())) {
+          if (classPath.length() > 0) {
+            classPath.append(java.io.File.pathSeparatorChar);
+          }
+          classPath.append(u.getFile());
+        }
+      }
+    }
+    env.setProperty("java.class.path", classPath.toString());
+
+    console = findClass("org.python.util.InteractiveConsole");
+    pyObject = findClass("org.python.core.PyObject");
+    pySystemState = findClass("org.python.core.PySystemState");
+
+    runMethod(
+        pySystemState,
+        pySystemState,
+        "initialize",
+        new Class<?>[] {Properties.class, Properties.class},
+        new Object[] {null, env});
+
+    try {
+      shell = console.getConstructor(new Class<?>[] {}).newInstance();
+      log.info("Jython shell instance created.");
+    } catch (InstantiationException
+        | IllegalAccessException
+        | IllegalArgumentException
+        | InvocationTargetException
+        | NoSuchMethodException
+        | SecurityException e) {
+      throw noInterpreter(e);
+    }
+    injectedVariables = new ArrayList<>();
+    set("Shell", this);
+  }
+
+  protected Object runMethod0(
+      Class<?> klazz, Object instance, String name, Class<?>[] sig, Object[] args)
+      throws InvocationTargetException {
+    try {
+      Method m;
+      m = klazz.getMethod(name, sig);
+      return m.invoke(instance, args);
+    } catch (NoSuchMethodException
+        | IllegalAccessException
+        | IllegalArgumentException
+        | SecurityException e) {
+      throw cannotStart(e);
+    }
+  }
+
+  protected Object runMethod(
+      Class<?> klazz, Object instance, String name, Class<?>[] sig, Object[] args) {
+    try {
+      return runMethod0(klazz, instance, name, sig, args);
+    } catch (InvocationTargetException e) {
+      throw cannotStart(e);
+    }
+  }
+
+  protected Object runInterpreter(String name, Class<?>[] sig, Object[] args) {
+    return runMethod(console, shell, name, sig, args);
+  }
+
+  protected String getDefaultBanner() {
+    return (String) runInterpreter("getDefaultBanner", new Class<?>[] {}, new Object[] {});
+  }
+
+  protected void printInjectedVariable(String id) {
+    runInterpreter(
+        "exec",
+        new Class<?>[] {String.class},
+        new Object[] {"print '\"%s\" is \"%s\"' % (\"" + id + "\", " + id + ")"});
+  }
+
+  public void run() {
+    for (String key : injectedVariables) {
+      printInjectedVariable(key);
+    }
+    reload();
+    runInterpreter(
+        "interact",
+        new Class<?>[] {String.class, pyObject},
+        new Object[] {
+          getDefaultBanner()
+              + " running for Gerrit "
+              + com.google.gerrit.common.Version.getVersion(),
+          null,
+        });
+  }
+
+  public void set(String key, Object content) {
+    runInterpreter("set", new Class<?>[] {String.class, Object.class}, new Object[] {key, content});
+    injectedVariables.add(key);
+  }
+
+  private static Class<?> findClass(String klazzname) {
+    try {
+      return Class.forName(klazzname);
+    } catch (ClassNotFoundException e) {
+      throw noShell("Class " + klazzname + " not found", e);
+    }
+  }
+
+  public void reload() {
+    execResource(STARTUP_RESOURCE);
+    execFile(GerritLauncher.getHomeDirectory(), STARTUP_FILE);
+  }
+
+  protected void execResource(String p) {
+    try (InputStream in = JythonShell.class.getClassLoader().getResourceAsStream(p)) {
+      if (in != null) {
+        execStream(in, "resource " + p);
+      } else {
+        log.error("Cannot load resource " + p);
+      }
+    } catch (IOException e) {
+      log.error(e.getMessage(), e);
+    }
+  }
+
+  protected void execFile(File parent, String p) {
+    try {
+      File script = new File(parent, p);
+      if (script.canExecute()) {
+        runMethod0(
+            console,
+            shell,
+            "execfile",
+            new Class<?>[] {String.class},
+            new Object[] {script.getAbsolutePath()});
+      } else {
+        log.info(
+            "User initialization file "
+                + script.getAbsolutePath()
+                + " is not found or not executable");
+      }
+    } catch (InvocationTargetException e) {
+      log.error("Exception occurred while loading file " + p + " : ", e);
+    } catch (SecurityException e) {
+      log.error("SecurityException occurred while loading file " + p + " : ", e);
+    }
+  }
+
+  protected void execStream(InputStream in, String p) {
+    try {
+      runMethod0(
+          console,
+          shell,
+          "execfile",
+          new Class<?>[] {InputStream.class, String.class},
+          new Object[] {in, p});
+    } catch (InvocationTargetException e) {
+      log.error("Exception occurred while loading " + p + " : ", e);
+    }
+  }
+
+  private static UnsupportedOperationException noShell(String m, Throwable why) {
+    final String prefix = "Cannot create Jython shell: ";
+    final String postfix = "\n     (You might need to install jython.jar in the lib directory)";
+    return new UnsupportedOperationException(prefix + m + postfix, why);
+  }
+
+  private static UnsupportedOperationException noInterpreter(Throwable why) {
+    final String msg = "Cannot create Python interpreter";
+    return noShell(msg, why);
+  }
+
+  private static UnsupportedOperationException cannotStart(Throwable why) {
+    final String msg = "Cannot start Jython shell";
+    return new UnsupportedOperationException(msg, why);
+  }
+}