folder reorganization

lib/js2py/internals/code.py

@@ -0,0 +1,197 @@
+from opcodes import *
+from space import *
+from base import *
+
+
+class Code:
+    '''Can generate, store and run sequence of ops representing js code'''
+
+    def __init__(self, is_strict=False):
+        self.tape = []
+        self.compiled = False
+        self.label_locs = None
+        self.is_strict = is_strict
+
+        self.contexts = []
+        self.current_ctx = None
+        self.return_locs = []
+        self._label_count = 0
+        self.label_locs = None
+
+        # useful references
+        self.GLOBAL_THIS = None
+        self.space = None
+
+    def get_new_label(self):
+        self._label_count += 1
+        return self._label_count
+
+    def emit(self, op_code, *args):
+        ''' Adds op_code with specified args to tape '''
+        self.tape.append(OP_CODES[op_code](*args))
+
+    def compile(self, start_loc=0):
+        ''' Records locations of labels and compiles the code '''
+        self.label_locs = {} if self.label_locs is None else self.label_locs
+        loc = start_loc
+        while loc < len(self.tape):
+            if type(self.tape[loc]) == LABEL:
+                self.label_locs[self.tape[loc].num] = loc
+                del self.tape[loc]
+                continue
+            loc += 1
+        self.compiled = True
+
+    def _call(self, func, this, args):
+        ''' Calls a bytecode function func
+            NOTE:  use !ONLY! when calling functions from native methods! '''
+        assert not func.is_native
+        # fake call - the the runner to return to the end of the file
+        old_contexts = self.contexts
+        old_return_locs = self.return_locs
+        old_curr_ctx = self.current_ctx
+
+        self.contexts = [FakeCtx()]
+        self.return_locs = [len(self.tape)]  # target line after return
+
+        # prepare my ctx
+        my_ctx = func._generate_my_context(this, args)
+        self.current_ctx = my_ctx
+
+        # execute dunction
+        ret = self.run(my_ctx, starting_loc=self.label_locs[func.code])
+
+        # bring back old execution
+        self.current_ctx = old_curr_ctx
+        self.contexts = old_contexts
+        self.return_locs = old_return_locs
+
+        return ret
+
+    def execute_fragment_under_context(self, ctx, start_label, end_label):
+        ''' just like run but returns if moved outside of the specified fragment
+            # 4 different exectution results
+            # 0=normal, 1=return, 2=jump_outside, 3=errors
+            # execute_fragment_under_context returns:
+            # (return_value, typ, return_value/jump_loc/py_error)
+            # ctx.stack must be len 1 and its always empty after the call.
+        '''
+        old_curr_ctx = self.current_ctx
+        try:
+            self.current_ctx = ctx
+            return self._execute_fragment_under_context(
+                ctx, start_label, end_label)
+        except JsException as err:
+            # undo the things that were put on the stack (if any)
+            # don't worry, I know the recovery is possible through try statement and for this reason try statement
+            # has its own context and stack so it will not delete the contents of the outer stack
+            del ctx.stack[:]
+            return undefined, 3, err
+        finally:
+            self.current_ctx = old_curr_ctx
+
+    def _execute_fragment_under_context(self, ctx, start_label, end_label):
+        start, end = self.label_locs[start_label], self.label_locs[end_label]
+        initial_len = len(ctx.stack)
+        loc = start
+        entry_level = len(self.contexts)
+        # for e in self.tape[start:end]:
+        #     print e
+
+        while loc < len(self.tape):
+            #print loc, self.tape[loc]
+            if len(self.contexts) == entry_level and loc >= end:
+                assert loc == end
+                assert len(ctx.stack) == (
+                    1 + initial_len), 'Stack change must be equal to +1!'
+                return ctx.stack.pop(), 0, None  # means normal return
+
+            # execute instruction
+            status = self.tape[loc].eval(ctx)
+
+            # check status for special actions
+            if status is not None:
+                if type(status) == int:  # jump to label
+                    loc = self.label_locs[status]
+                    if len(self.contexts) == entry_level:
+                        # check if jumped outside of the fragment and break if so
+                        if not start <= loc < end:
+                            assert len(ctx.stack) == (
+                                1 + initial_len
+                            ), 'Stack change must be equal to +1!'
+                            return ctx.stack.pop(), 2, status  # jump outside
+                    continue
+
+                elif len(status) == 2:  # a call or a return!
+                    # call: (new_ctx, func_loc_label_num)
+                    if status[0] is not None:
+                        # append old state to the stack
+                        self.contexts.append(ctx)
+                        self.return_locs.append(loc + 1)
+                        # set new state
+                        loc = self.label_locs[status[1]]
+                        ctx = status[0]
+                        self.current_ctx = ctx
+                        continue
+
+                    # return: (None, None)
+                    else:
+                        if len(self.contexts) == entry_level:
+                            assert len(ctx.stack) == 1 + initial_len
+                            return undefined, 1, ctx.stack.pop(
+                            )  # return signal
+                        return_value = ctx.stack.pop()
+                        ctx = self.contexts.pop()
+                        self.current_ctx = ctx
+                        ctx.stack.append(return_value)
+
+                        loc = self.return_locs.pop()
+                        continue
+            # next instruction
+            loc += 1
+        assert False, 'Remember to add NOP at the end!'
+
+    def run(self, ctx, starting_loc=0):
+        loc = starting_loc
+        self.current_ctx = ctx
+        while loc < len(self.tape):
+            # execute instruction
+            #print loc, self.tape[loc]
+            status = self.tape[loc].eval(ctx)
+
+            # check status for special actions
+            if status is not None:
+                if type(status) == int:  # jump to label
+                    loc = self.label_locs[status]
+                    continue
+
+                elif len(status) == 2:  # a call or a return!
+                    # call: (new_ctx, func_loc_label_num)
+                    if status[0] is not None:
+                        # append old state to the stack
+                        self.contexts.append(ctx)
+                        self.return_locs.append(loc + 1)
+                        # set new state
+                        loc = self.label_locs[status[1]]
+                        ctx = status[0]
+                        self.current_ctx = ctx
+                        continue
+
+                    # return: (None, None)
+                    else:
+                        return_value = ctx.stack.pop()
+                        ctx = self.contexts.pop()
+                        self.current_ctx = ctx
+                        ctx.stack.append(return_value)
+
+                        loc = self.return_locs.pop()
+                        continue
+            # next instruction
+            loc += 1
+        assert len(ctx.stack) == 1, ctx.stack
+        return ctx.stack.pop()
+
+
+class FakeCtx(object):
+    def __init__(self):
+        self.stack = []