mirror of https://github.com/morpheus65535/bazarr
198 lines
7.3 KiB
Python
198 lines
7.3 KiB
Python
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from opcodes import *
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from space import *
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from base import *
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class Code:
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'''Can generate, store and run sequence of ops representing js code'''
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def __init__(self, is_strict=False):
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self.tape = []
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self.compiled = False
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self.label_locs = None
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self.is_strict = is_strict
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self.contexts = []
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self.current_ctx = None
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self.return_locs = []
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self._label_count = 0
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self.label_locs = None
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# useful references
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self.GLOBAL_THIS = None
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self.space = None
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def get_new_label(self):
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self._label_count += 1
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return self._label_count
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def emit(self, op_code, *args):
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''' Adds op_code with specified args to tape '''
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self.tape.append(OP_CODES[op_code](*args))
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def compile(self, start_loc=0):
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''' Records locations of labels and compiles the code '''
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self.label_locs = {} if self.label_locs is None else self.label_locs
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loc = start_loc
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while loc < len(self.tape):
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if type(self.tape[loc]) == LABEL:
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self.label_locs[self.tape[loc].num] = loc
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del self.tape[loc]
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continue
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loc += 1
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self.compiled = True
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def _call(self, func, this, args):
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''' Calls a bytecode function func
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NOTE: use !ONLY! when calling functions from native methods! '''
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assert not func.is_native
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# fake call - the the runner to return to the end of the file
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old_contexts = self.contexts
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old_return_locs = self.return_locs
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old_curr_ctx = self.current_ctx
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self.contexts = [FakeCtx()]
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self.return_locs = [len(self.tape)] # target line after return
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# prepare my ctx
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my_ctx = func._generate_my_context(this, args)
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self.current_ctx = my_ctx
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# execute dunction
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ret = self.run(my_ctx, starting_loc=self.label_locs[func.code])
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# bring back old execution
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self.current_ctx = old_curr_ctx
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self.contexts = old_contexts
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self.return_locs = old_return_locs
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return ret
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def execute_fragment_under_context(self, ctx, start_label, end_label):
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''' just like run but returns if moved outside of the specified fragment
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# 4 different exectution results
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# 0=normal, 1=return, 2=jump_outside, 3=errors
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# execute_fragment_under_context returns:
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# (return_value, typ, return_value/jump_loc/py_error)
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# ctx.stack must be len 1 and its always empty after the call.
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'''
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old_curr_ctx = self.current_ctx
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try:
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self.current_ctx = ctx
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return self._execute_fragment_under_context(
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ctx, start_label, end_label)
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except JsException as err:
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# undo the things that were put on the stack (if any)
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# don't worry, I know the recovery is possible through try statement and for this reason try statement
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# has its own context and stack so it will not delete the contents of the outer stack
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del ctx.stack[:]
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return undefined, 3, err
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finally:
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self.current_ctx = old_curr_ctx
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def _execute_fragment_under_context(self, ctx, start_label, end_label):
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start, end = self.label_locs[start_label], self.label_locs[end_label]
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initial_len = len(ctx.stack)
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loc = start
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entry_level = len(self.contexts)
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# for e in self.tape[start:end]:
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# print e
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while loc < len(self.tape):
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#print loc, self.tape[loc]
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if len(self.contexts) == entry_level and loc >= end:
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assert loc == end
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assert len(ctx.stack) == (
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1 + initial_len), 'Stack change must be equal to +1!'
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return ctx.stack.pop(), 0, None # means normal return
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# execute instruction
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status = self.tape[loc].eval(ctx)
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# check status for special actions
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if status is not None:
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if type(status) == int: # jump to label
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loc = self.label_locs[status]
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if len(self.contexts) == entry_level:
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# check if jumped outside of the fragment and break if so
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if not start <= loc < end:
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assert len(ctx.stack) == (
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1 + initial_len
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), 'Stack change must be equal to +1!'
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return ctx.stack.pop(), 2, status # jump outside
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continue
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elif len(status) == 2: # a call or a return!
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# call: (new_ctx, func_loc_label_num)
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if status[0] is not None:
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# append old state to the stack
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self.contexts.append(ctx)
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self.return_locs.append(loc + 1)
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# set new state
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loc = self.label_locs[status[1]]
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ctx = status[0]
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self.current_ctx = ctx
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continue
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# return: (None, None)
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else:
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if len(self.contexts) == entry_level:
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assert len(ctx.stack) == 1 + initial_len
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return undefined, 1, ctx.stack.pop(
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) # return signal
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return_value = ctx.stack.pop()
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ctx = self.contexts.pop()
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self.current_ctx = ctx
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ctx.stack.append(return_value)
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loc = self.return_locs.pop()
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continue
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# next instruction
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loc += 1
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assert False, 'Remember to add NOP at the end!'
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def run(self, ctx, starting_loc=0):
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loc = starting_loc
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self.current_ctx = ctx
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while loc < len(self.tape):
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# execute instruction
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#print loc, self.tape[loc]
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status = self.tape[loc].eval(ctx)
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# check status for special actions
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if status is not None:
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if type(status) == int: # jump to label
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loc = self.label_locs[status]
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continue
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elif len(status) == 2: # a call or a return!
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# call: (new_ctx, func_loc_label_num)
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if status[0] is not None:
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# append old state to the stack
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self.contexts.append(ctx)
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self.return_locs.append(loc + 1)
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# set new state
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loc = self.label_locs[status[1]]
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ctx = status[0]
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self.current_ctx = ctx
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continue
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# return: (None, None)
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else:
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return_value = ctx.stack.pop()
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ctx = self.contexts.pop()
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self.current_ctx = ctx
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ctx.stack.append(return_value)
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loc = self.return_locs.pop()
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continue
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# next instruction
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loc += 1
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assert len(ctx.stack) == 1, ctx.stack
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return ctx.stack.pop()
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class FakeCtx(object):
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def __init__(self):
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self.stack = []
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