line-directive

#!/usr/bin/env python
# line-directive.py - Transform line numbers in error messages -*- python -*-
#
# This source file is part of the Swift.org open source project
#
# Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
# Licensed under Apache License v2.0 with Runtime Library Exception
#
# See https://swift.org/LICENSE.txt for license information
# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
#
# ----------------------------------------------------------------------------
from __future__ import print_function

import bisect
import os
import re
import shlex
import subprocess
import sys

usage = '''"#sourceLocation" is a directive used by tools like the Swift
compiler and debugger to adjust the lines reported in diagnostics and to
determine what source you see when you're stepping. "#sourceLocation"
corresponds to "#line" in C/C++ which is inserted by code generators like
Lex/Flex/Yacc/Bison so that you deal with the actual code you wrote and not the
generated result. For dealing with errors in the Swift generated by your gyb
source it's important that your tools can take you to the right line in your
.gyb file rather than in generated .swift file. If you don't have such a tool,
manually indirecting through the generated code is tedious, but at least it's
possible since gyb leaves "#sourceLocation" information behind.

But Swift's "#sourceLocation" directive is suboptimal for the purposes of the
freeform code generation done with gyb because it can only appear between
grammatically-complete declarations and statements (or something like that). So
instead of inserting "#sourceLocation" directives, gyb inserts "//
###sourceLocation" comments (by default---it's tunable). This line-directive
tool remaps file and line information in the output of your swift compiler (or
whatever tool you are using to process generated source---gyb is not
swift-specific) so that the error points to the right place in the .gyb
source. You invoke it as follows:

  line-directive <generated-sources> -- <compilation command>

e.g., if you have foo.swift.gyb, bar.swift.gyb, and baz.swift, instead of

  gyb foo.swift.gyb -o foo.swift
  gyb bar.swift.gyb -o bar.swift
  swiftc foo.swift bar.swift baz.swift

You do this:

  gyb foo.swift.gyb -o foo.swift
  gyb bar.swift.gyb -o bar.swift
  line-directive foo.swift bar.swift -- swiftc foo.swift bar.swift baz.swift
'''

line_pattern = re.compile(
    r'^// ###sourceLocation\(file:\s*"([^"]+)",\s*line:\s*([0-9]+)\s*\)')


def _make_line_map(target_filename, stream=None):
    """
    >>> from StringIO import StringIO
    >>> _make_line_map('box',
    ... StringIO('''// ###sourceLocation(file: "foo.bar", line: 3)
    ... line 2
    ... line 3
    ... line 4
    ... // ###sourceLocation(file: "baz.txt", line: 20)
    ... line 6
    ... line 7
    ... '''))
    [(0, 'box', 1), (1, 'foo.bar', 3), (5, 'baz.txt', 20)]
    """
    result = [(0, target_filename, 1)]
    input = stream or open(target_filename)
    for i, l in enumerate(input.readlines()):
        m = line_pattern.match(l)
        if m:
            result.append((i + 1, m.group(1), int(m.group(2))))
    return result


_line_maps = {}


def fline_map(target_filename):
    map = _line_maps.get(target_filename)
    if map is None:
        map = _make_line_map(target_filename)
        _line_maps[target_filename] = map
    return map


def map_line_to_source_file(target_filename, target_line_num):
    """
    >>> from tempfile import *
    >>> # On Windows, the name of a NamedTemporaryFile cannot be used to open
    >>> # the file for a second time if delete=True. Therefore, we have to
    >>> # manually handle closing and deleting this file to allow us to open
    >>> # the file by its name across all platforms.
    >>> t = NamedTemporaryFile(delete=False)
    >>> t.write('''line 1
    ... line 2
    ... // ###sourceLocation(file: "foo.bar", line: 20)
    ... line 4
    ... line 5
    ... // ###sourceLocation(file: "baz.txt", line: 5)
    ... line 7
    ... line 8
    ... ''')
    >>> t.flush()
    >>> (t2, l) = map_line_to_source_file(t.name, 1)
    >>> t2 == t.name, l
    (True, 1)
    >>> (t2, l) = map_line_to_source_file(t.name, 2)
    >>> t2 == t.name, l
    (True, 2)
    >>> (t2, l) = map_line_to_source_file(t.name, 3)
    >>> t2 == t.name, l
    (True, 3)
    >>> map_line_to_source_file(t.name, 4)
    ('foo.bar', 20)
    >>> map_line_to_source_file(t.name, 5)
    ('foo.bar', 21)
    >>> map_line_to_source_file(t.name, 6)
    ('foo.bar', 22)
    >>> map_line_to_source_file(t.name, 7)
    ('baz.txt', 5)
    >>> map_line_to_source_file(t.name, 8)
    ('baz.txt', 6)
    >>> map_line_to_source_file(t.name, 42)
    ('baz.txt', 40)
    >>> t.close()
    >>> os.remove(t.name)
    """
    assert(target_line_num > 0)
    map = fline_map(target_filename)
    index = bisect.bisect_left(map, (target_line_num, '', 0))
    base = map[index - 1]
    return base[1], base[2] + (target_line_num - base[0] - 1)


def map_line_from_source_file(source_filename, source_line_num,
                              target_filename):
    """
    >>> from tempfile import *
    >>> # On Windows, the name of a NamedTemporaryFile cannot be used to open
    >>> # the file for a second time if delete=True. Therefore, we have to
    >>> # manually handle closing and deleting this file to allow us to open
    >>> # the file by its name across all platforms.
    >>> t = NamedTemporaryFile(delete=False)
    >>> t.write('''line 1
    ... line 2
    ... // ###sourceLocation(file: "foo.bar", line: 20)
    ... line 4
    ... line 5
    ... // ###sourceLocation(file: "baz.txt", line: 5)
    ... line 7
    ... line 8
    ... ''')
    >>> t.flush()
    >>> map_line_from_source_file(t.name, 1, t.name)
    1
    >>> map_line_from_source_file(t.name, 2, t.name)
    2
    >>> map_line_from_source_file(t.name, 3, t.name)
    3
    >>> try: map_line_from_source_file(t.name, 4, t.name)
    ... except RuntimeError: pass
    >>> try: map_line_from_source_file('foo.bar', 19, t.name)
    ... except RuntimeError: pass
    >>> map_line_from_source_file('foo.bar', 20, t.name)
    4
    >>> map_line_from_source_file('foo.bar', 21, t.name)
    5
    >>> map_line_from_source_file('foo.bar', 22, t.name)
    6
    >>> try: map_line_from_source_file('foo.bar', 23, t.name)
    ... except RuntimeError: pass
    >>> map_line_from_source_file('baz.txt', 5, t.name)
    7
    >>> map_line_from_source_file('baz.txt', 6, t.name)
    8
    >>> map_line_from_source_file('baz.txt', 33, t.name)
    35
    >>> try: map_line_from_source_file(t.name, 33, t.name)
    ... except RuntimeError: pass
    >>> try: map_line_from_source_file('foo.bar', 2, t.name)
    ... except RuntimeError: pass
    >>> t.close()
    >>> os.remove(t.name)
    """
    assert(source_line_num > 0)
    map = fline_map(target_filename)

    for i, (target_line_num, found_source_filename,
            found_source_line_num) in enumerate(map):
        if found_source_filename != source_filename:
            continue
        if found_source_line_num > source_line_num:
            continue
        result = target_line_num + (source_line_num - found_source_line_num)
        if i + 1 == len(map) or map[i + 1][0] > result:
            return result + 1
    raise RuntimeError("line not found")


def read_response_file(file_path):
    with open(file_path, 'r') as files:
        # "Make an iterator out of shlex.shlex.get_token, then consume items
        # until it returns None." (Then eagerly convert the result to a list so
        # that we can close the file.)
        return list(iter(shlex.shlex(files, file_path, posix=True).get_token,
                         None))


def expand_response_files(files):
    expanded_files = []
    for file_path in files:
        # Read a list of files from a response file.
        if file_path[0] == '@':
            expanded_files.extend(read_response_file(file_path[1:]))
        else:
            expanded_files.append(file_path)

    return expanded_files


def run():
    """Simulate a couple of gyb-generated files

    >>> from tempfile import *
    >>> # On Windows, the name of a NamedTemporaryFile cannot be used to open
    >>> # the file for a second time if delete=True. Therefore, we have to
    >>> # manually handle closing and deleting this file to allow us to open
    >>> # the file by its name across all platforms.
    >>> target1 = NamedTemporaryFile(delete=False)
    >>> target1.write('''line 1
    ... line 2
    ... // ###sourceLocation(file: "foo.bar", line: 20)
    ... line 4
    ... line 5
    ... // ###sourceLocation(file: "baz.txt", line: 5)
    ... line 7
    ... line 8
    ... ''')
    >>> target1.flush()
    >>> # On Windows, the name of a NamedTemporaryFile cannot be used to open
    >>> # the file for a second time if delete=True. Therefore, we have to
    >>> # manually handle closing and deleting this file to allow us to open
    >>> # the file by its name across all platforms.
    >>> target2 = NamedTemporaryFile(delete=False)
    >>> target2.write('''// ###sourceLocation(file: "foo.bar", line: 7)
    ... line 2
    ... line 3
    ... // ###sourceLocation(file: "fox.box", line: 11)
    ... line 5
    ... line 6
    ... ''')
    >>> target2.flush()

    Simulate the raw output of compilation

    >>> # On Windows, the name of a NamedTemporaryFile cannot be used to open
    >>> # the file for a second time if delete=True. Therefore, we have to
    >>> # manually handle closing and deleting this file to allow us to open
    >>> # the file by its name across all platforms.
    >>> raw_output = NamedTemporaryFile(delete=False)
    >>> target1_name, target2_name = target1.name, target2.name
    >>> raw_output.write('''A
    ... %(target1_name)s:2:111: error one
    ... B
    ... %(target1_name)s:4:222: error two
    ... C
    ... %(target1_name)s:8:333: error three
    ... D
    ... glitch in file %(target2_name)s:1 assert one
    ... E
    ... glitch in file %(target2_name)s, line 2 assert two
    ... glitch at %(target2_name)s, line 3 assert three
    ... glitch at %(target2_name)s:4 assert four
    ... glitch in [%(target2_name)s, line 5 assert five
    ... glitch in [%(target2_name)s:22 assert six
    ... ''' % locals())
    >>> raw_output.flush()

    Run this tool on the two targets, using a portable version of Unix 'cat' to
    dump the output file.

    >>> import subprocess
    >>> output = subprocess.check_output([sys.executable,
    ...    __file__, target1.name, target2.name, '--',
    ...    sys.executable, '-c',
    ...   'import sys;sys.stdout.write(open(sys.argv[1]).read())',
    ...   raw_output.name], universal_newlines=True)

    Replace temporary filenames and check it.

    >>> print(output.replace(target1.name,'TARGET1-NAME')
    ...             .replace(target2.name,'TARGET2-NAME') + 'EOF')
    A
    TARGET1-NAME:2:111: error one
    B
    foo.bar:20:222: error two
    C
    baz.txt:6:333: error three
    D
    glitch in file TARGET2-NAME:1 assert one
    E
    glitch in file foo.bar, line 7 assert two
    glitch at foo.bar, line 8 assert three
    glitch at foo.bar:9 assert four
    glitch in [fox.box, line 11 assert five
    glitch in [fox.box:28 assert six
    EOF
    >>> print(subprocess.check_output([sys.executable, __file__, 'foo.bar',
    ...                                '21', target1.name],
    ...                               universal_newlines=True), end='')
    5
    >>> print(subprocess.check_output([sys.executable, __file__, 'foo.bar',
    ...                                '8', target2.name],
    ...                               universal_newlines=True), end='')
    3

    Simulate errors on different line numbers
    >>> # On Windows, the name of a NamedTemporaryFile cannot be used to open
    >>> # the file for a second time if delete=True. Therefore, we have to
    >>> # manually handle closing and deleting this file to allow us to open
    >>> # the file by its name across all platforms.
    >>> long_output = NamedTemporaryFile(delete=False)
    >>> long_output.write('''
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 1)
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 1)
    ... //===--- Map.swift.gyb - Lazily map over a Sequence -----------*- swif
    ... //
    ... // This source file is part of the Swift.org open source project
    ... //
    ... // Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
    ... // Licensed under Apache License v2.0 with Runtime Library Exception
    ... //
    ... // See https://swift.org/LICENSE.txt for license information
    ... // See https://swift.org/CONTRIBUTORS.txt for the list of Swift projec
    ... //
    ... //===-----------------------------------------------------------------
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 20)
    ...
    ... /// The `IteratorProtocol` used by `MapSequence` and `MapCollection`.
    ... /// Produces each element by passing the output of the `Base`
    ... /// `IteratorProtocol` through a transform function returning
    ... @_fixed_layout
    ... public struct LazyMapIterator<
    ...   Base : IteratorProtocol, Element
    ... > : IteratorProtocol, Sequence {
    ...   /// Advances to the next element and returns it, or `nil` if no
    ...   /// exists.
    ...   ///
    ...   /// Once `nil` has been returned, all subsequent calls return `nil`.
    ...   ///
    ...   /// - Precondition: `next()` has not been applied to a copy.
    ...   ///   since the copy was made.
    ...   @_inlineable
    ...   public mutating func next() -> Element? {
    ...     return _base.next().map(_transform)
    ...   }
    ...
    ...   @_inlineable
    ...   public var base: Base { return _base }
    ...
    ...   @_versioned
    ...   internal var _base: Base
    ...   @_versioned
    ...   internal let _transform: (Base.Element) -> Element
    ...
    ...   @_inlineable
    ...   @_versioned
    ...   internal init(_base: Base, _transform: @escaping (Base.Element)
    ...     self._base = _base
    ...     self._transform = _transform
    ...   }
    ... }
    ...
    ... /// A `Sequence` whose elements consist of those in a `Base`
    ... /// `Sequence` passed through a transform function returning.
    ... /// These elements are computed lazily, each time they're read, by
    ... /// calling the transform function on a base element.
    ... @_fixed_layout
    ... public struct LazyMapSequence<Base : Sequence, Element>
    ...   : LazySequenceProtocol {
    ...
    ...   public typealias Elements = LazyMapSequence
    ...
    ...   /// Returns an iterator over the elements of this sequence.
    ...   ///
    ...   /// - Complexity: O(1).
    ...   @_inlineable
    ...   public func makeIterator() -> LazyMapIterator<Base.Iterator, Element
    ...     return LazyMapIterator(_base: _base.makeIterator(), _transform: _t
    ...   }
    ...
    ...   /// Returns a value less than or equal to the number of elements in
    ...   /// `self`, **nondestructively**.
    ...   ///
    ...   /// - Complexity: O(*n*)
    ...   @_inlineable
    ...   public var underestimatedCount: Int {
    ...     return _base.underestimatedCount
    ...   }
    ...
    ...   /// Creates an instance with elements `transform(x)` for each elemen
    ...   /// `x` of base.
    ...   @_inlineable
    ...   @_versioned
    ...   internal init(_base: Base, transform: @escaping (Base.Iterator.Eleme
    ...     self._base = _base
    ...     self._transform = transform
    ...   }
    ...
    ...   @_versioned
    ...   internal var _base: Base
    ...   @_versioned
    ...   internal let _transform: (Base.Iterator.Element) -> Element
    ... }
    ...
    ... //===--- Collections -------------------------------------------------
    ...
    ... // FIXME(ABI)#45 (Conditional Conformance): `LazyMap*Collection` types
    ... // collapsed into one `LazyMapCollection` using conditional conformanc
    ... // Maybe even combined with `LazyMapSequence`.
    ... // rdar://problem/17144340
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 108)
    ...
    ... /// A `Collection` whose elements consist of those in a `Base`
    ... /// `Collection` passed through a transform function returning `Elemen
    ... /// These elements are computed lazily, each time they're read, by
    ... /// calling the transform function on a base element.
    ... @_fixed_layout
    ... public struct LazyMapCollection<
    ...   Base : Collection, Element
    ... > : LazyCollectionProtocol,
    ...     _CollectionWrapper
    ... {
    ...   public typealias Base = Base_
    ...   public typealias Index = Base.Index
    ...   public typealias _Element = Base._Element
    ...   public typealias SubSequence = Base.SubSequence
    ...   typealias Indices = Base.Indices
    ...
    ...   @_inlineable
    ...   public subscript(position: Base.Index) -> Element {
    ...     return _transform(_base[position])
    ...   }
    ...
    ...   /// Create an instance with elements `transform(x)` for each element
    ...   /// `x` of base.
    ...   @_inlineable
    ...   @_versioned
    ...   internal init(_base: Base, transform: @escaping (Base.Iterator.Eleme
    ...     self._base = _base
    ...     self._transform = transform
    ...   }
    ...
    ...   @_versioned
    ...   internal var _base: Base
    ...   @_versioned
    ...   internal let _transform: (Base.Iterator.Element) -> Element
    ... }
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 108)
    ...
    ... /// A `Collection` whose elements consist of those in a `Base`
    ... /// `Collection` passed through a transform function returning `Elemen
    ... /// These elements are computed lazily, each time they're read, by
    ... /// calling the transform function on a base element.
    ... @_fixed_layout
    ... public struct LazyMapBidirectionalCollection<
    ...   Base : BidirectionalCollection, Element
    ... > : LazyCollectionProtocol,
    ...     _BidirectionalCollectionWrapper
    ... {
    ...   public typealias Base = Base_
    ...   public typealias Index = Base.Index
    ...   public typealias _Element = Base._Element
    ...   public typealias SubSequence = Base.SubSequence
    ...   typealias Indices = Base.Indices
    ...
    ...   @_inlineable
    ...   public subscript(position: Base.Index) -> Element {
    ...     return _transform(_base[position])
    ...   }
    ...
    ...   /// Create an instance with elements `transform(x)` for each element
    ...   /// `x` of base.
    ...   @_inlineable
    ...   @_versioned
    ...   internal init(_base: Base, transform: @escaping (Base.Iterator.Eleme
    ...     self._base = _base
    ...     self._transform = transform
    ...   }
    ...
    ...   @_versioned
    ...   internal var _base: Base
    ...   @_versioned
    ...   internal let _transform: (Base.Iterator.Element) -> Element
    ... }
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 108)
    ...
    ... /// A `Collection` whose elements consist of those in a `Base`
    ... /// `Collection` passed through a transform function returning `Elemen
    ... /// These elements are computed lazily, each time they're read, by
    ... /// calling the transform function on a base element.
    ... @_fixed_layout
    ... public struct LazyMapRandomAccessCollection<
    ...   Base : RandomAccessCollection, Element
    ... > : LazyCollectionProtocol,
    ...     _RandomAccessCollectionWrapper
    ... {
    ...   public typealias Base = Base_
    ...   public typealias Index = Base.Index
    ...   public typealias _Element = Base._Element
    ...   public typealias SubSequence = Base.SubSequence
    ...   typealias Indices = Base.Indices
    ...
    ...   @_inlineable
    ...   public subscript(position: Base.Index) -> Element {
    ...     return _transform(_base[position])
    ...   }
    ...
    ...   /// Create an instance with elements `transform(x)` for each element
    ...   /// `x` of base.
    ...   @_inlineable
    ...   @_versioned
    ...   internal init(_base: Base, transform: @escaping (Base.Iterator.Eleme
    ...     self._base = _base
    ...     self._transform = transform
    ...   }
    ...
    ...   @_versioned
    ...   internal var _base: Base
    ...   @_versioned
    ...   internal let _transform: (Base.Iterator.Element) -> Element
    ... }
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 146)
    ...
    ... //===--- Support for s.lazy ------------------------------------------
    ...
    ... extension LazySequenceProtocol {
    ...   /// Returns a `LazyMapSequence` over this `Sequence`.  The elements
    ...   /// the result are computed lazily, each time they are read, by
    ...   /// calling `transform` function on a base element.
    ...   @_inlineable
    ...   public func map<U>(
    ...     _ transform: @escaping (Elements.Iterator.Element) -> U
    ...   ) -> LazyMapSequence<Self.Elements, U> {
    ...     return LazyMapSequence(_base: self.elements, transform: transform)
    ...   }
    ... }
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 162)
    ...
    ... extension LazyCollectionProtocol
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 169)
    ... {
    ...   /// Returns a `LazyMapCollection` over this `Collection`.  The eleme
    ...   /// the result are computed lazily, each time they are read, by
    ...   /// calling `transform` function on a base element.
    ...   @_inlineable
    ...   public func map<U>(
    ...     _ transform: @escaping (Elements.Iterator.Element) -> U
    ...   ) -> LazyMapCollection<Self.Elements, U> {
    ...     return LazyMapCollection(
    ...       _base: self.elements,
    ...       transform: transform)
    ...   }
    ... }
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 162)
    ...
    ... extension LazyCollectionProtocol
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 165)
    ...   where
    ...   Self : BidirectionalCollection,
    ...   Elements : BidirectionalCollection
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 169)
    ... {
    ...   /// Returns a `LazyMapCollection` over this `Collection`.  The eleme
    ...   /// the result are computed lazily, each time they are read, by
    ...   /// calling `transform` function on a base element.
    ...   @_inlineable
    ...   public func map<U>(
    ...     _ transform: @escaping (Elements.Iterator.Element) -> U
    ...   ) -> LazyMapBidirectionalCollection<Self.Elements, U> {
    ...     return LazyMapBidirectionalCollection(
    ...       _base: self.elements,
    ...       transform: transform)
    ...   }
    ... }
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 162)
    ...
    ... extension LazyCollectionProtocol
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 165)
    ...   where
    ...   Self : RandomAccessCollection,
    ...   Elements : RandomAccessCollection
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 169)
    ... {
    ...   /// Returns a `LazyMapCollection` over this `Collection`.  The eleme
    ...   /// the result are computed lazily, each time they are read, by
    ...   /// calling `transform` function on a base element.
    ...   @_inlineable
    ...   public func map<U>(
    ...     _ transform: @escaping (Elements.Iterator.Element) -> U
    ...   ) -> LazyMapRandomAccessCollection<Self.Elements, U> {
    ...     return LazyMapRandomAccessCollection(
    ...       _base: self.elements,
    ...       transform: transform)
    ...   }
    ... }
    ...
    ... // ###sourceLocation(file: "/public/core/Map.swift.gyb", line: 184)
    ...
    ... @available(*, unavailable, renamed: "LazyMapIterator")
    ... public struct LazyMapGenerator<Base : IteratorProtocol, Element> {}
    ...
    ... extension LazyMapSequence {
    ...   @available(*, unavailable, message: "use '.lazy.map' on the sequence
    ...   public init(_ base: Base, transform: (Base.Iterator.Element) -> Elem
    ...     Builtin.unreachable()
    ...   }
    ... }
    ...
    ... extension LazyMapCollection {
    ...   @available(*, unavailable, message: "use '.lazy.map' on the collecti
    ...   public init(_ base: Base, transform: (Base.Iterator.Element) -> Elem
    ...     Builtin.unreachable()
    ...   }
    ... }
    ...
    ... // Local Variables:
    ... // eval: (read-only-mode 1)
    ... // End:
    ... ''')
    >>> long_output.flush()
    >>> long_output_result = subprocess.check_output([sys.executable,
    ...    __file__, long_output.name, '--',
    ...    'echo', long_output.name + ':112:27: error:']).rstrip()
    >>> print(long_output_result)
    /public/core/Map.swift.gyb:117:27: error:
    >>> target1.close()
    >>> os.remove(target1.name)
    >>> target2.close()
    >>> os.remove(target2.name)
    >>> raw_output.close()
    >>> os.remove(raw_output.name)

    """
    if len(sys.argv) <= 1:
        import doctest
        failure_count, _ = doctest.testmod()
        sys.exit(failure_count)
    elif len(sys.argv) == 2 and sys.argv[1] == '--help':
        print(usage)
        sys.exit(1)
    elif '--' not in sys.argv:
        source_file = sys.argv[1]
        source_line = int(sys.argv[2])
        target_file = sys.argv[3]
        print(map_line_from_source_file(source_file, source_line, target_file))
    else:
        dashes = sys.argv.index('--')
        sources = expand_response_files(sys.argv[1:dashes])

        # The first argument of command_args is the process to open.
        # subprocess.Popen doesn't normalize arguments. This means that trying
        # to open a non-normalized file (e.g. C:/swift/./bin/swiftc.exe) on
        # Windows results in file/directory not found errors, as Popen
        # delegates to the Win32 CreateProcess API. Unix systems handle
        # non-normalized paths, so don't have this problem.
        # Arguments passed to the process are normalized by the process.
        command_args = expand_response_files(sys.argv[dashes + 1:])
        command_args[0] = os.path.normpath(command_args[0])

        command = subprocess.Popen(
            command_args,
            stderr=subprocess.STDOUT,
            stdout=subprocess.PIPE,
            universal_newlines=True
        )

        sources = '(?P<file>' + '|'.join(re.escape(s) for s in sources) + ')'

        error_pattern = re.compile(
            '^' + sources +
            ':(?P<line>[0-9]+):(?P<column>[0-9]+):(?P<tail>.*?)\n?$')

        assertion_pattern = re.compile(
            '^(?P<head>.*( file | at |#[0-9]+: |[\[]))' +
            sources +
            '(?P<middle>, line |:)(?P<line>[0-9]+)(?P<tail>.*?)\n?$')

        while True:
            input = command.stdout.readline()
            if input == '':
                break
            output = input

            def decode_match(p, l):
                m = p.match(l)
                if m is None:
                    return ()
                file, line_num = map_line_to_source_file(
                    m.group('file'), int(m.group('line')))
                return ((m, file, line_num),)

            for (m, file, line_num) in decode_match(error_pattern, input):
                output = '%s:%s:%s:%s\n' % (
                    file, line_num, int(m.group(3)), m.group(4))
                break
            else:
                for (m, file, line_num) in decode_match(assertion_pattern,
                                                        input):
                    output = '%s%s%s%s%s\n' % (
                        m.group('head'), file, m.group('middle'), line_num,
                        m.group('tail'))
            sys.stdout.write(output)

        sys.exit(command.wait())


if __name__ == '__main__':
    run()