Add a class-loading module.

diff --git a/classfile/classpath.py b/classfile/classpath.py
new file mode 100644 (file)
index 0000000..2b82406
--- /dev/null
+++ b/classfile/classpath.py
@@ -0,0 +1,48 @@
+import os, zipfile
+from . import file
+
+class dir(object):
+    def __init__(self, path):
+        self.path = path
+
+    def get(self, name):
+        if '.' in name:
+            raise FileNotFoundError(name)
+        els = name.split('/')
+        fn = os.path.join(self.path, *els[:-1], els[-1] + ".class")
+        with open(fn, "rb") as fp:
+            return file.classfile.load(fp)
+
+class jar(object):
+    def __init__(self, filename):
+        self.filename = filename
+
+    def get(self, name):
+        with zipfile.ZipFile(self.filename) as jar:
+            fn = name + ".class"
+            try:
+                fp = jar.open(fn, "r")
+            except KeyError:
+                raise FileNotFoundError(name)
+            with fp:
+                return file.classfile.load(fp)
+
+class path(object):
+    def __init__(self, *ents, caching=True):
+        self.ents = ents
+        self.cache = {} if caching else None
+
+    def get(self, name):
+        if self.cache is not None and name in self.cache:
+            return self.cache[name]
+        for ent in self.ents:
+            try:
+                ret = ent.get(name)
+                break;
+            except FileNotFoundError:
+                pass
+        else:
+            raise FileNotFoundError(name)
+        if self.cache is not None:
+            self.cache[name] = ret
+        return ret