Add control of JVM startup options

docs/source/api.rst

@@ -327,3 +327,19 @@ example::
       Signature: ()V
     }
 
+
+JVM options and the class path
+------------------------------
+
+JVM options need to be set before `import jnius` is called, as they cannot be changed after the VM starts up.
+To this end, you can::
+
+    import jnius_config
+    jnius_config.add_options('-Xrs', '-Xmx4096')
+    jnius_config.set_classpath('.', '/usr/local/fem/plugins/*')
+    import jnius
+
+If a classpath is set with these functions, it overrides any CLASSPATH environment variable.
+Multiple options or path entries should be supplied as multiple arguments to the `add_` and `set_` functions.
+If no classpath is provided and CLASSPATH is not set, the path defaults to `'.'`.
+This functionality is not available on Android.

jnius/jnius_env.pxi

@@ -4,11 +4,13 @@ cdef JNIEnv *default_env = NULL
 cdef extern int gettid()
 cdef JavaVM *jvm = NULL
 
-cdef JNIEnv *get_jnienv():
+cdef JNIEnv *get_jnienv() except NULL:
     global default_env
     # first call, init.
     if default_env == NULL:
         default_env = get_platform_jnienv()
+        if default_env == NULL:
+            return NULL
         default_env[0].GetJavaVM(default_env, &jvm)
 
     # return the current env attached to the thread

jnius/jnius_jvm_desktop.pxi

@@ -4,6 +4,7 @@
 cdef extern jint __stdcall JNI_CreateJavaVM(JavaVM **pvm, void **penv, void *args)
 cdef extern from "jni.h":
     int JNI_VERSION_1_4
+    int JNI_OK
     jboolean JNI_FALSE
     ctypedef struct JavaVMInitArgs:
         jint version
@@ -16,52 +17,36 @@ cdef extern from "jni.h":
 
 cdef JNIEnv *_platform_default_env = NULL
 
-def classpath():
-    import platform
-    from glob import glob
-    from os import environ
-    from os.path import realpath, dirname, join
-
-    if platform.system() == 'Windows':
-        split_char = ';'
-    else:
-        split_char = ':'
-
-    paths = [realpath('.'), join(dirname(__file__), 'src'), ]
-    if 'CLASSPATH' not in environ:
-        return split_char.join(paths)
-
-    cp = environ.get('CLASSPATH')
-    pre_paths = paths + cp.split(split_char)
-    # deal with wildcards
-    for path in pre_paths:
-        if not path.endswith('*'):
-            paths.append(path)
-        else:
-            paths.extend(glob(path + '.jar'))
-            paths.extend(glob(path + '.JAR'))
-    result = split_char.join(paths)
-    return result
-
-cdef void create_jnienv():
+cdef void create_jnienv() except *:
     cdef JavaVM* jvm
     cdef JavaVMInitArgs args
-    cdef JavaVMOption options[1]
+    cdef JavaVMOption *options
+    cdef int ret
     cdef bytes py_bytes
+    import jnius_config
 
-    cp = classpath()
-    py_bytes = <bytes>('-Djava.class.path={0}'.format(cp))
-    options[0].optionString = py_bytes
-    options[0].extraInfo = NULL
+    optarr = jnius_config.options
+    optarr.append("-Djava.class.path=" + jnius_config.expand_classpath())
+
+    options = <JavaVMOption*>malloc(sizeof(JavaVMOption) * len(optarr))
+    for i, opt in enumerate(optarr):
+        options[i].optionString = <bytes>(opt)
+        options[i].extraInfo = NULL
 
     args.version = JNI_VERSION_1_4
     args.options = options
-    args.nOptions = 1
+    args.nOptions = len(optarr)
     args.ignoreUnrecognized = JNI_FALSE
 
-    JNI_CreateJavaVM(&jvm, <void **>&_platform_default_env, &args)
+    ret = JNI_CreateJavaVM(&jvm, <void **>&_platform_default_env, &args)
+    free(options)
 
-cdef JNIEnv *get_platform_jnienv():
+    if ret != JNI_OK:
+        raise SystemError("JVM failed to start")
+
+    jnius_config.vm_running = True
+
+cdef JNIEnv *get_platform_jnienv() except NULL:
     if _platform_default_env == NULL:
         create_jnienv()
     return _platform_default_env

jnius_config.py

@@ -0,0 +1,79 @@
+__all__ = ('set_options', 'add_options', 'get_options',
+           'set_classpath', 'add_classpath', 'get_classpath',
+           'expand_classpath')
+
+import platform
+if platform.system() == 'Windows':
+    split_char = ';'
+else:
+    split_char = ':'
+
+vm_running = False
+options = []
+classpath = None
+
+def set_options(*opts):
+    "Sets the list of options to the JVM. Removes any previously set options."
+    if vm_running:
+        raise ValueError("VM is already running, can't set options")
+    globals()['options'] = opts
+
+def add_options(*opts):
+    "Appends options to the list of VM options."
+    if vm_running:
+        raise ValueError("VM is already running, can't set options")
+    global options
+    options.extend(opts)
+
+def get_options():
+    "Retrieves the current list of VM options."
+    global options
+    return list(options)
+
+
+def set_classpath(*path):
+    """
+    Sets the classpath for the JVM to use. Replaces any existing classpath, overriding the CLASSPATH environment variable.
+    """
+    if vm_running:
+        raise ValueError("VM is already running, can't set classpath")
+    global classpath
+    classpath = path
+
+def add_classpath(*path):
+    """
+    Appends items to the classpath for the JVM to use.
+    Replaces any existing classpath, overriding the CLASSPATH environment variable.
+    """
+    if vm_running:
+        raise ValueError("VM is already running, can't set classpath")
+    global classpath
+    if classpath is None:
+        classpath = list(path)
+    else:
+        classpath.extend(path)
+
+def get_classpath():
+    "Retrieves the classpath the JVM will use."
+    from os import environ
+    from os.path import realpath
+    global classpath
+
+    if classpath is not None:
+        return list(classpath)
+
+    if 'CLASSPATH' in environ:
+        return environ['CLASSPATH'].split(split_char)
+
+    return [realpath('.')]
+
+def expand_classpath():
+    from glob import glob
+    paths = []
+    # deal with wildcards
+    for path in get_classpath():
+        if not path.endswith('*'):
+            paths.append(path)
+        else:
+            paths.extend(glob(path + '.[Jj][Aa][Rr]'))
+    return split_char.join(paths)

setup.py

@@ -108,6 +108,7 @@ setup(name='jnius',
       version=version,
       cmdclass={'build_ext': build_ext},
       packages=['jnius'],
+      py_modules=['jnius_config'],
       url='http://pyjnius.readthedocs.org/',
       author='Mathieu Virbel and Gabriel Pettier',
       author_email='mat@kivy.org,gabriel@kivy.org',