| """Code parsing for Coverage.""" |
| |
| import dis, re, sys, token, tokenize |
| |
| from coverage.backward import set, sorted, StringIO # pylint: disable=W0622 |
| from coverage.backward import open_source, range # pylint: disable=W0622 |
| from coverage.backward import reversed # pylint: disable=W0622 |
| from coverage.backward import bytes_to_ints |
| from coverage.bytecode import ByteCodes, CodeObjects |
| from coverage.misc import nice_pair, expensive, join_regex |
| from coverage.misc import CoverageException, NoSource, NotPython |
| |
| |
| class CodeParser(object): |
| """Parse code to find executable lines, excluded lines, etc.""" |
| |
| def __init__(self, text=None, filename=None, exclude=None): |
| """ |
| Source can be provided as `text`, the text itself, or `filename`, from |
| which the text will be read. Excluded lines are those that match |
| `exclude`, a regex. |
| |
| """ |
| assert text or filename, "CodeParser needs either text or filename" |
| self.filename = filename or "<code>" |
| self.text = text |
| if not self.text: |
| try: |
| sourcef = open_source(self.filename) |
| try: |
| self.text = sourcef.read() |
| finally: |
| sourcef.close() |
| except IOError: |
| _, err, _ = sys.exc_info() |
| raise NoSource( |
| "No source for code: '%s': %s" % (self.filename, err) |
| ) |
| |
| # Scrap the BOM if it exists. |
| if self.text and ord(self.text[0]) == 0xfeff: |
| self.text = self.text[1:] |
| |
| self.exclude = exclude |
| |
| self.show_tokens = False |
| |
| # The text lines of the parsed code. |
| self.lines = self.text.split('\n') |
| |
| # The line numbers of excluded lines of code. |
| self.excluded = set() |
| |
| # The line numbers of docstring lines. |
| self.docstrings = set() |
| |
| # The line numbers of class definitions. |
| self.classdefs = set() |
| |
| # A dict mapping line numbers to (lo,hi) for multi-line statements. |
| self.multiline = {} |
| |
| # The line numbers that start statements. |
| self.statement_starts = set() |
| |
| # Lazily-created ByteParser |
| self._byte_parser = None |
| |
| def _get_byte_parser(self): |
| """Create a ByteParser on demand.""" |
| if not self._byte_parser: |
| self._byte_parser = \ |
| ByteParser(text=self.text, filename=self.filename) |
| return self._byte_parser |
| byte_parser = property(_get_byte_parser) |
| |
| def lines_matching(self, *regexes): |
| """Find the lines matching one of a list of regexes. |
| |
| Returns a set of line numbers, the lines that contain a match for one |
| of the regexes in `regexes`. The entire line needn't match, just a |
| part of it. |
| |
| """ |
| regex_c = re.compile(join_regex(regexes)) |
| matches = set() |
| for i, ltext in enumerate(self.lines): |
| if regex_c.search(ltext): |
| matches.add(i+1) |
| return matches |
| |
| def _raw_parse(self): |
| """Parse the source to find the interesting facts about its lines. |
| |
| A handful of member fields are updated. |
| |
| """ |
| # Find lines which match an exclusion pattern. |
| if self.exclude: |
| self.excluded = self.lines_matching(self.exclude) |
| |
| # Tokenize, to find excluded suites, to find docstrings, and to find |
| # multi-line statements. |
| indent = 0 |
| exclude_indent = 0 |
| excluding = False |
| prev_toktype = token.INDENT |
| first_line = None |
| empty = True |
| |
| tokgen = tokenize.generate_tokens(StringIO(self.text).readline) |
| for toktype, ttext, (slineno, _), (elineno, _), ltext in tokgen: |
| if self.show_tokens: # pragma: not covered |
| print("%10s %5s %-20r %r" % ( |
| tokenize.tok_name.get(toktype, toktype), |
| nice_pair((slineno, elineno)), ttext, ltext |
| )) |
| if toktype == token.INDENT: |
| indent += 1 |
| elif toktype == token.DEDENT: |
| indent -= 1 |
| elif toktype == token.NAME and ttext == 'class': |
| # Class definitions look like branches in the byte code, so |
| # we need to exclude them. The simplest way is to note the |
| # lines with the 'class' keyword. |
| self.classdefs.add(slineno) |
| elif toktype == token.OP and ttext == ':': |
| if not excluding and elineno in self.excluded: |
| # Start excluding a suite. We trigger off of the colon |
| # token so that the #pragma comment will be recognized on |
| # the same line as the colon. |
| exclude_indent = indent |
| excluding = True |
| elif toktype == token.STRING and prev_toktype == token.INDENT: |
| # Strings that are first on an indented line are docstrings. |
| # (a trick from trace.py in the stdlib.) This works for |
| # 99.9999% of cases. For the rest (!) see: |
| # http://stackoverflow.com/questions/1769332/x/1769794#1769794 |
| self.docstrings.update(range(slineno, elineno+1)) |
| elif toktype == token.NEWLINE: |
| if first_line is not None and elineno != first_line: |
| # We're at the end of a line, and we've ended on a |
| # different line than the first line of the statement, |
| # so record a multi-line range. |
| rng = (first_line, elineno) |
| for l in range(first_line, elineno+1): |
| self.multiline[l] = rng |
| first_line = None |
| |
| if ttext.strip() and toktype != tokenize.COMMENT: |
| # A non-whitespace token. |
| empty = False |
| if first_line is None: |
| # The token is not whitespace, and is the first in a |
| # statement. |
| first_line = slineno |
| # Check whether to end an excluded suite. |
| if excluding and indent <= exclude_indent: |
| excluding = False |
| if excluding: |
| self.excluded.add(elineno) |
| |
| prev_toktype = toktype |
| |
| # Find the starts of the executable statements. |
| if not empty: |
| self.statement_starts.update(self.byte_parser._find_statements()) |
| |
| def first_line(self, line): |
| """Return the first line number of the statement including `line`.""" |
| rng = self.multiline.get(line) |
| if rng: |
| first_line = rng[0] |
| else: |
| first_line = line |
| return first_line |
| |
| def first_lines(self, lines, ignore=None): |
| """Map the line numbers in `lines` to the correct first line of the |
| statement. |
| |
| Skip any line mentioned in `ignore`. |
| |
| Returns a sorted list of the first lines. |
| |
| """ |
| ignore = ignore or [] |
| lset = set() |
| for l in lines: |
| if l in ignore: |
| continue |
| new_l = self.first_line(l) |
| if new_l not in ignore: |
| lset.add(new_l) |
| return sorted(lset) |
| |
| def parse_source(self): |
| """Parse source text to find executable lines, excluded lines, etc. |
| |
| Return values are 1) a sorted list of executable line numbers, and |
| 2) a sorted list of excluded line numbers. |
| |
| Reported line numbers are normalized to the first line of multi-line |
| statements. |
| |
| """ |
| try: |
| self._raw_parse() |
| except (tokenize.TokenError, IndentationError): |
| _, tokerr, _ = sys.exc_info() |
| msg, lineno = tokerr.args |
| raise NotPython( |
| "Couldn't parse '%s' as Python source: '%s' at %s" % |
| (self.filename, msg, lineno) |
| ) |
| |
| excluded_lines = self.first_lines(self.excluded) |
| ignore = excluded_lines + list(self.docstrings) |
| lines = self.first_lines(self.statement_starts, ignore) |
| |
| return lines, excluded_lines |
| |
| def arcs(self): |
| """Get information about the arcs available in the code. |
| |
| Returns a sorted list of line number pairs. Line numbers have been |
| normalized to the first line of multiline statements. |
| |
| """ |
| all_arcs = [] |
| for l1, l2 in self.byte_parser._all_arcs(): |
| fl1 = self.first_line(l1) |
| fl2 = self.first_line(l2) |
| if fl1 != fl2: |
| all_arcs.append((fl1, fl2)) |
| return sorted(all_arcs) |
| arcs = expensive(arcs) |
| |
| def exit_counts(self): |
| """Get a mapping from line numbers to count of exits from that line. |
| |
| Excluded lines are excluded. |
| |
| """ |
| excluded_lines = self.first_lines(self.excluded) |
| exit_counts = {} |
| for l1, l2 in self.arcs(): |
| if l1 < 0: |
| # Don't ever report -1 as a line number |
| continue |
| if l1 in excluded_lines: |
| # Don't report excluded lines as line numbers. |
| continue |
| if l2 in excluded_lines: |
| # Arcs to excluded lines shouldn't count. |
| continue |
| if l1 not in exit_counts: |
| exit_counts[l1] = 0 |
| exit_counts[l1] += 1 |
| |
| # Class definitions have one extra exit, so remove one for each: |
| for l in self.classdefs: |
| # Ensure key is there: classdefs can include excluded lines. |
| if l in exit_counts: |
| exit_counts[l] -= 1 |
| |
| return exit_counts |
| exit_counts = expensive(exit_counts) |
| |
| |
| ## Opcodes that guide the ByteParser. |
| |
| def _opcode(name): |
| """Return the opcode by name from the dis module.""" |
| return dis.opmap[name] |
| |
| def _opcode_set(*names): |
| """Return a set of opcodes by the names in `names`.""" |
| s = set() |
| for name in names: |
| try: |
| s.add(_opcode(name)) |
| except KeyError: |
| pass |
| return s |
| |
| # Opcodes that leave the code object. |
| OPS_CODE_END = _opcode_set('RETURN_VALUE') |
| |
| # Opcodes that unconditionally end the code chunk. |
| OPS_CHUNK_END = _opcode_set( |
| 'JUMP_ABSOLUTE', 'JUMP_FORWARD', 'RETURN_VALUE', 'RAISE_VARARGS', |
| 'BREAK_LOOP', 'CONTINUE_LOOP', |
| ) |
| |
| # Opcodes that unconditionally begin a new code chunk. By starting new chunks |
| # with unconditional jump instructions, we neatly deal with jumps to jumps |
| # properly. |
| OPS_CHUNK_BEGIN = _opcode_set('JUMP_ABSOLUTE', 'JUMP_FORWARD') |
| |
| # Opcodes that push a block on the block stack. |
| OPS_PUSH_BLOCK = _opcode_set( |
| 'SETUP_LOOP', 'SETUP_EXCEPT', 'SETUP_FINALLY', 'SETUP_WITH' |
| ) |
| |
| # Block types for exception handling. |
| OPS_EXCEPT_BLOCKS = _opcode_set('SETUP_EXCEPT', 'SETUP_FINALLY') |
| |
| # Opcodes that pop a block from the block stack. |
| OPS_POP_BLOCK = _opcode_set('POP_BLOCK') |
| |
| # Opcodes that have a jump destination, but aren't really a jump. |
| OPS_NO_JUMP = OPS_PUSH_BLOCK |
| |
| # Individual opcodes we need below. |
| OP_BREAK_LOOP = _opcode('BREAK_LOOP') |
| OP_END_FINALLY = _opcode('END_FINALLY') |
| OP_COMPARE_OP = _opcode('COMPARE_OP') |
| COMPARE_EXCEPTION = 10 # just have to get this const from the code. |
| OP_LOAD_CONST = _opcode('LOAD_CONST') |
| OP_RETURN_VALUE = _opcode('RETURN_VALUE') |
| |
| |
| class ByteParser(object): |
| """Parse byte codes to understand the structure of code.""" |
| |
| def __init__(self, code=None, text=None, filename=None): |
| if code: |
| self.code = code |
| self.text = text |
| else: |
| if not text: |
| assert filename, "If no code or text, need a filename" |
| sourcef = open_source(filename) |
| try: |
| text = sourcef.read() |
| finally: |
| sourcef.close() |
| self.text = text |
| |
| try: |
| # Python 2.3 and 2.4 don't like partial last lines, so be sure |
| # the text ends nicely for them. |
| self.code = compile(text + '\n', filename, "exec") |
| except SyntaxError: |
| _, synerr, _ = sys.exc_info() |
| raise NotPython( |
| "Couldn't parse '%s' as Python source: '%s' at line %d" % |
| (filename, synerr.msg, synerr.lineno) |
| ) |
| |
| # Alternative Python implementations don't always provide all the |
| # attributes on code objects that we need to do the analysis. |
| for attr in ['co_lnotab', 'co_firstlineno', 'co_consts', 'co_code']: |
| if not hasattr(self.code, attr): |
| raise CoverageException( |
| "This implementation of Python doesn't support code " |
| "analysis.\n" |
| "Run coverage.py under CPython for this command." |
| ) |
| |
| def child_parsers(self): |
| """Iterate over all the code objects nested within this one. |
| |
| The iteration includes `self` as its first value. |
| |
| """ |
| children = CodeObjects(self.code) |
| return [ByteParser(code=c, text=self.text) for c in children] |
| |
| def _bytes_lines(self): |
| """Map byte offsets to line numbers in `code`. |
| |
| Uses co_lnotab described in Python/compile.c to map byte offsets to |
| line numbers. Produces a sequence: (b0, l0), (b1, l1), ... |
| |
| Only byte offsets that correspond to line numbers are included in the |
| results. |
| |
| """ |
| # Adapted from dis.py in the standard library. |
| byte_increments = bytes_to_ints(self.code.co_lnotab[0::2]) |
| line_increments = bytes_to_ints(self.code.co_lnotab[1::2]) |
| |
| last_line_num = None |
| line_num = self.code.co_firstlineno |
| byte_num = 0 |
| for byte_incr, line_incr in zip(byte_increments, line_increments): |
| if byte_incr: |
| if line_num != last_line_num: |
| yield (byte_num, line_num) |
| last_line_num = line_num |
| byte_num += byte_incr |
| line_num += line_incr |
| if line_num != last_line_num: |
| yield (byte_num, line_num) |
| |
| def _find_statements(self): |
| """Find the statements in `self.code`. |
| |
| Produce a sequence of line numbers that start statements. Recurses |
| into all code objects reachable from `self.code`. |
| |
| """ |
| for bp in self.child_parsers(): |
| # Get all of the lineno information from this code. |
| for _, l in bp._bytes_lines(): |
| yield l |
| |
| def _block_stack_repr(self, block_stack): |
| """Get a string version of `block_stack`, for debugging.""" |
| blocks = ", ".join( |
| ["(%s, %r)" % (dis.opname[b[0]], b[1]) for b in block_stack] |
| ) |
| return "[" + blocks + "]" |
| |
| def _split_into_chunks(self): |
| """Split the code object into a list of `Chunk` objects. |
| |
| Each chunk is only entered at its first instruction, though there can |
| be many exits from a chunk. |
| |
| Returns a list of `Chunk` objects. |
| |
| """ |
| # The list of chunks so far, and the one we're working on. |
| chunks = [] |
| chunk = None |
| |
| # A dict mapping byte offsets of line starts to the line numbers. |
| bytes_lines_map = dict(self._bytes_lines()) |
| |
| # The block stack: loops and try blocks get pushed here for the |
| # implicit jumps that can occur. |
| # Each entry is a tuple: (block type, destination) |
| block_stack = [] |
| |
| # Some op codes are followed by branches that should be ignored. This |
| # is a count of how many ignores are left. |
| ignore_branch = 0 |
| |
| # We have to handle the last two bytecodes specially. |
| ult = penult = None |
| |
| # Get a set of all of the jump-to points. |
| jump_to = set() |
| for bc in ByteCodes(self.code.co_code): |
| if bc.jump_to >= 0: |
| jump_to.add(bc.jump_to) |
| |
| chunk_lineno = 0 |
| |
| # Walk the byte codes building chunks. |
| for bc in ByteCodes(self.code.co_code): |
| # Maybe have to start a new chunk |
| start_new_chunk = False |
| first_chunk = False |
| if bc.offset in bytes_lines_map: |
| # Start a new chunk for each source line number. |
| start_new_chunk = True |
| chunk_lineno = bytes_lines_map[bc.offset] |
| first_chunk = True |
| elif bc.offset in jump_to: |
| # To make chunks have a single entrance, we have to make a new |
| # chunk when we get to a place some bytecode jumps to. |
| start_new_chunk = True |
| elif bc.op in OPS_CHUNK_BEGIN: |
| # Jumps deserve their own unnumbered chunk. This fixes |
| # problems with jumps to jumps getting confused. |
| start_new_chunk = True |
| |
| if not chunk or start_new_chunk: |
| if chunk: |
| chunk.exits.add(bc.offset) |
| chunk = Chunk(bc.offset, chunk_lineno, first_chunk) |
| chunks.append(chunk) |
| |
| # Look at the opcode |
| if bc.jump_to >= 0 and bc.op not in OPS_NO_JUMP: |
| if ignore_branch: |
| # Someone earlier wanted us to ignore this branch. |
| ignore_branch -= 1 |
| else: |
| # The opcode has a jump, it's an exit for this chunk. |
| chunk.exits.add(bc.jump_to) |
| |
| if bc.op in OPS_CODE_END: |
| # The opcode can exit the code object. |
| chunk.exits.add(-self.code.co_firstlineno) |
| if bc.op in OPS_PUSH_BLOCK: |
| # The opcode adds a block to the block_stack. |
| block_stack.append((bc.op, bc.jump_to)) |
| if bc.op in OPS_POP_BLOCK: |
| # The opcode pops a block from the block stack. |
| block_stack.pop() |
| if bc.op in OPS_CHUNK_END: |
| # This opcode forces the end of the chunk. |
| if bc.op == OP_BREAK_LOOP: |
| # A break is implicit: jump where the top of the |
| # block_stack points. |
| chunk.exits.add(block_stack[-1][1]) |
| chunk = None |
| if bc.op == OP_END_FINALLY: |
| # For the finally clause we need to find the closest exception |
| # block, and use its jump target as an exit. |
| for block in reversed(block_stack): |
| if block[0] in OPS_EXCEPT_BLOCKS: |
| chunk.exits.add(block[1]) |
| break |
| if bc.op == OP_COMPARE_OP and bc.arg == COMPARE_EXCEPTION: |
| # This is an except clause. We want to overlook the next |
| # branch, so that except's don't count as branches. |
| ignore_branch += 1 |
| |
| penult = ult |
| ult = bc |
| |
| if chunks: |
| # The last two bytecodes could be a dummy "return None" that |
| # shouldn't be counted as real code. Every Python code object seems |
| # to end with a return, and a "return None" is inserted if there |
| # isn't an explicit return in the source. |
| if ult and penult: |
| if penult.op == OP_LOAD_CONST and ult.op == OP_RETURN_VALUE: |
| if self.code.co_consts[penult.arg] is None: |
| # This is "return None", but is it dummy? A real line |
| # would be a last chunk all by itself. |
| if chunks[-1].byte != penult.offset: |
| ex = -self.code.co_firstlineno |
| # Split the last chunk |
| last_chunk = chunks[-1] |
| last_chunk.exits.remove(ex) |
| last_chunk.exits.add(penult.offset) |
| chunk = Chunk( |
| penult.offset, last_chunk.line, False |
| ) |
| chunk.exits.add(ex) |
| chunks.append(chunk) |
| |
| # Give all the chunks a length. |
| chunks[-1].length = bc.next_offset - chunks[-1].byte # pylint: disable=W0631,C0301 |
| for i in range(len(chunks)-1): |
| chunks[i].length = chunks[i+1].byte - chunks[i].byte |
| |
| #self.validate_chunks(chunks) |
| return chunks |
| |
| def validate_chunks(self, chunks): |
| """Validate the rule that chunks have a single entrance.""" |
| # starts is the entrances to the chunks |
| starts = set([ch.byte for ch in chunks]) |
| for ch in chunks: |
| assert all([(ex in starts or ex < 0) for ex in ch.exits]) |
| |
| def _arcs(self): |
| """Find the executable arcs in the code. |
| |
| Yields pairs: (from,to). From and to are integer line numbers. If |
| from is < 0, then the arc is an entrance into the code object. If to |
| is < 0, the arc is an exit from the code object. |
| |
| """ |
| chunks = self._split_into_chunks() |
| |
| # A map from byte offsets to chunks jumped into. |
| byte_chunks = dict([(c.byte, c) for c in chunks]) |
| |
| # There's always an entrance at the first chunk. |
| yield (-1, byte_chunks[0].line) |
| |
| # Traverse from the first chunk in each line, and yield arcs where |
| # the trace function will be invoked. |
| for chunk in chunks: |
| if not chunk.first: |
| continue |
| |
| chunks_considered = set() |
| chunks_to_consider = [chunk] |
| while chunks_to_consider: |
| # Get the chunk we're considering, and make sure we don't |
| # consider it again |
| this_chunk = chunks_to_consider.pop() |
| chunks_considered.add(this_chunk) |
| |
| # For each exit, add the line number if the trace function |
| # would be triggered, or add the chunk to those being |
| # considered if not. |
| for ex in this_chunk.exits: |
| if ex < 0: |
| yield (chunk.line, ex) |
| else: |
| next_chunk = byte_chunks[ex] |
| if next_chunk in chunks_considered: |
| continue |
| |
| # The trace function is invoked if visiting the first |
| # bytecode in a line, or if the transition is a |
| # backward jump. |
| backward_jump = next_chunk.byte < this_chunk.byte |
| if next_chunk.first or backward_jump: |
| if next_chunk.line != chunk.line: |
| yield (chunk.line, next_chunk.line) |
| else: |
| chunks_to_consider.append(next_chunk) |
| |
| def _all_chunks(self): |
| """Returns a list of `Chunk` objects for this code and its children. |
| |
| See `_split_into_chunks` for details. |
| |
| """ |
| chunks = [] |
| for bp in self.child_parsers(): |
| chunks.extend(bp._split_into_chunks()) |
| |
| return chunks |
| |
| def _all_arcs(self): |
| """Get the set of all arcs in this code object and its children. |
| |
| See `_arcs` for details. |
| |
| """ |
| arcs = set() |
| for bp in self.child_parsers(): |
| arcs.update(bp._arcs()) |
| |
| return arcs |
| |
| |
| class Chunk(object): |
| """A sequence of byte codes with a single entrance. |
| |
| To analyze byte code, we have to divide it into chunks, sequences of byte |
| codes such that each chunk has only one entrance, the first instruction in |
| the block. |
| |
| This is almost the CS concept of `basic block`_, except that we're willing |
| to have many exits from a chunk, and "basic block" is a more cumbersome |
| term. |
| |
| .. _basic block: http://en.wikipedia.org/wiki/Basic_block |
| |
| `line` is the source line number containing this chunk. |
| |
| `first` is true if this is the first chunk in the source line. |
| |
| An exit < 0 means the chunk can leave the code (return). The exit is |
| the negative of the starting line number of the code block. |
| |
| """ |
| def __init__(self, byte, line, first): |
| self.byte = byte |
| self.line = line |
| self.first = first |
| self.length = 0 |
| self.exits = set() |
| |
| def __repr__(self): |
| if self.first: |
| bang = "!" |
| else: |
| bang = "" |
| return "<%d+%d @%d%s %r>" % ( |
| self.byte, self.length, self.line, bang, list(self.exits) |
| ) |
