Mercurial > hg
view mercurial/encoding.py @ 39559:07b58266bce3
wireprotov2: implement commands as a generator of objects
Previously, wire protocol version 2 inherited version 1's model of
having separate types to represent the results of different wire
protocol commands.
As I implemented more powerful commands in future commits, I found
I was using a common pattern of returning a special type to hold a
generator. This meant the command function required a closure to
do most of the work. That made logic flow more difficult to follow.
I also noticed that many commands were effectively a sequence of
objects to be CBOR encoded.
I think it makes sense to define version 2 commands as generators.
This way, commands can simply emit the data structures they wish to
send to the client. This eliminates the need for a closure in
command functions and removes encoding from the bodies of commands.
As part of this commit, the handling of response objects has been
moved into the serverreactor class. This puts the reactor in the
driver's seat with regards to CBOR encoding and error handling.
Having error handling in the function that emits frames is
particularly important because exceptions in that function can lead
to things getting in a bad state: I'm fairly certain that uncaught
exceptions in the frame generator were causing deadlocks.
I also introduced a dedicated error type for explicit error reporting
in command handlers. This will be used in subsequent commits.
There's still a bit of work to be done here, especially around
formalizing the error handling "protocol." I've added yet another
TODO to track this so we don't forget.
Test output changed because we're using generators and no longer know
we are at the end of the data until we hit the end of the generator.
This means we can't emit the end-of-stream flag until we've exhausted
the generator. Hence the introduction of 0-sized end-of-stream frames.
Differential Revision: https://phab.mercurial-scm.org/D4472
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 05 Sep 2018 09:06:40 -0700 |
parents | e7aa113b14f7 |
children | 24e493ec2229 |
line wrap: on
line source
# encoding.py - character transcoding support for Mercurial # # Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import, print_function import locale import os import unicodedata from . import ( error, policy, pycompat, ) from .pure import ( charencode as charencodepure, ) charencode = policy.importmod(r'charencode') isasciistr = charencode.isasciistr asciilower = charencode.asciilower asciiupper = charencode.asciiupper _jsonescapeu8fast = charencode.jsonescapeu8fast _sysstr = pycompat.sysstr if pycompat.ispy3: unichr = chr # These unicode characters are ignored by HFS+ (Apple Technote 1150, # "Unicode Subtleties"), so we need to ignore them in some places for # sanity. _ignore = [unichr(int(x, 16)).encode("utf-8") for x in "200c 200d 200e 200f 202a 202b 202c 202d 202e " "206a 206b 206c 206d 206e 206f feff".split()] # verify the next function will work assert all(i.startswith(("\xe2", "\xef")) for i in _ignore) def hfsignoreclean(s): """Remove codepoints ignored by HFS+ from s. >>> hfsignoreclean(u'.h\u200cg'.encode('utf-8')) '.hg' >>> hfsignoreclean(u'.h\ufeffg'.encode('utf-8')) '.hg' """ if "\xe2" in s or "\xef" in s: for c in _ignore: s = s.replace(c, '') return s # encoding.environ is provided read-only, which may not be used to modify # the process environment _nativeenviron = (not pycompat.ispy3 or os.supports_bytes_environ) if not pycompat.ispy3: environ = os.environ # re-exports elif _nativeenviron: environ = os.environb # re-exports else: # preferred encoding isn't known yet; use utf-8 to avoid unicode error # and recreate it once encoding is settled environ = dict((k.encode(u'utf-8'), v.encode(u'utf-8')) for k, v in os.environ.items()) # re-exports _encodingfixers = { '646': lambda: 'ascii', 'ANSI_X3.4-1968': lambda: 'ascii', } # cp65001 is a Windows variant of utf-8, which isn't supported on Python 2. # No idea if it should be rewritten to the canonical name 'utf-8' on Python 3. # https://bugs.python.org/issue13216 if pycompat.iswindows and not pycompat.ispy3: _encodingfixers['cp65001'] = lambda: 'utf-8' try: encoding = environ.get("HGENCODING") if not encoding: encoding = locale.getpreferredencoding().encode('ascii') or 'ascii' encoding = _encodingfixers.get(encoding, lambda: encoding)() except locale.Error: encoding = 'ascii' encodingmode = environ.get("HGENCODINGMODE", "strict") fallbackencoding = 'ISO-8859-1' class localstr(bytes): '''This class allows strings that are unmodified to be round-tripped to the local encoding and back''' def __new__(cls, u, l): s = bytes.__new__(cls, l) s._utf8 = u return s def __hash__(self): return hash(self._utf8) # avoid collisions in local string space class safelocalstr(bytes): """Tagged string denoting it was previously an internal UTF-8 string, and can be converted back to UTF-8 losslessly >>> assert safelocalstr(b'\\xc3') == b'\\xc3' >>> assert b'\\xc3' == safelocalstr(b'\\xc3') >>> assert b'\\xc3' in {safelocalstr(b'\\xc3'): 0} >>> assert safelocalstr(b'\\xc3') in {b'\\xc3': 0} """ def tolocal(s): """ Convert a string from internal UTF-8 to local encoding All internal strings should be UTF-8 but some repos before the implementation of locale support may contain latin1 or possibly other character sets. We attempt to decode everything strictly using UTF-8, then Latin-1, and failing that, we use UTF-8 and replace unknown characters. The localstr class is used to cache the known UTF-8 encoding of strings next to their local representation to allow lossless round-trip conversion back to UTF-8. >>> u = b'foo: \\xc3\\xa4' # utf-8 >>> l = tolocal(u) >>> l 'foo: ?' >>> fromlocal(l) 'foo: \\xc3\\xa4' >>> u2 = b'foo: \\xc3\\xa1' >>> d = { l: 1, tolocal(u2): 2 } >>> len(d) # no collision 2 >>> b'foo: ?' in d False >>> l1 = b'foo: \\xe4' # historical latin1 fallback >>> l = tolocal(l1) >>> l 'foo: ?' >>> fromlocal(l) # magically in utf-8 'foo: \\xc3\\xa4' """ if isasciistr(s): return s try: try: # make sure string is actually stored in UTF-8 u = s.decode('UTF-8') if encoding == 'UTF-8': # fast path return s r = u.encode(_sysstr(encoding), u"replace") if u == r.decode(_sysstr(encoding)): # r is a safe, non-lossy encoding of s return safelocalstr(r) return localstr(s, r) except UnicodeDecodeError: # we should only get here if we're looking at an ancient changeset try: u = s.decode(_sysstr(fallbackencoding)) r = u.encode(_sysstr(encoding), u"replace") if u == r.decode(_sysstr(encoding)): # r is a safe, non-lossy encoding of s return safelocalstr(r) return localstr(u.encode('UTF-8'), r) except UnicodeDecodeError: u = s.decode("utf-8", "replace") # last ditch # can't round-trip return u.encode(_sysstr(encoding), u"replace") except LookupError as k: raise error.Abort(k, hint="please check your locale settings") def fromlocal(s): """ Convert a string from the local character encoding to UTF-8 We attempt to decode strings using the encoding mode set by HGENCODINGMODE, which defaults to 'strict'. In this mode, unknown characters will cause an error message. Other modes include 'replace', which replaces unknown characters with a special Unicode character, and 'ignore', which drops the character. """ # can we do a lossless round-trip? if isinstance(s, localstr): return s._utf8 if isasciistr(s): return s try: u = s.decode(_sysstr(encoding), _sysstr(encodingmode)) return u.encode("utf-8") except UnicodeDecodeError as inst: sub = s[max(0, inst.start - 10):inst.start + 10] raise error.Abort("decoding near '%s': %s!" % (sub, pycompat.bytestr(inst))) except LookupError as k: raise error.Abort(k, hint="please check your locale settings") def unitolocal(u): """Convert a unicode string to a byte string of local encoding""" return tolocal(u.encode('utf-8')) def unifromlocal(s): """Convert a byte string of local encoding to a unicode string""" return fromlocal(s).decode('utf-8') def unimethod(bytesfunc): """Create a proxy method that forwards __unicode__() and __str__() of Python 3 to __bytes__()""" def unifunc(obj): return unifromlocal(bytesfunc(obj)) return unifunc # converter functions between native str and byte string. use these if the # character encoding is not aware (e.g. exception message) or is known to # be locale dependent (e.g. date formatting.) if pycompat.ispy3: strtolocal = unitolocal strfromlocal = unifromlocal strmethod = unimethod else: strtolocal = pycompat.identity strfromlocal = pycompat.identity strmethod = pycompat.identity if not _nativeenviron: # now encoding and helper functions are available, recreate the environ # dict to be exported to other modules environ = dict((tolocal(k.encode(u'utf-8')), tolocal(v.encode(u'utf-8'))) for k, v in os.environ.items()) # re-exports # How to treat ambiguous-width characters. Set to 'wide' to treat as wide. _wide = _sysstr(environ.get("HGENCODINGAMBIGUOUS", "narrow") == "wide" and "WFA" or "WF") def colwidth(s): "Find the column width of a string for display in the local encoding" return ucolwidth(s.decode(_sysstr(encoding), u'replace')) def ucolwidth(d): "Find the column width of a Unicode string for display" eaw = getattr(unicodedata, 'east_asian_width', None) if eaw is not None: return sum([eaw(c) in _wide and 2 or 1 for c in d]) return len(d) def getcols(s, start, c): '''Use colwidth to find a c-column substring of s starting at byte index start''' for x in pycompat.xrange(start + c, len(s)): t = s[start:x] if colwidth(t) == c: return t def trim(s, width, ellipsis='', leftside=False): """Trim string 's' to at most 'width' columns (including 'ellipsis'). If 'leftside' is True, left side of string 's' is trimmed. 'ellipsis' is always placed at trimmed side. >>> from .node import bin >>> def bprint(s): ... print(pycompat.sysstr(s)) >>> ellipsis = b'+++' >>> from . import encoding >>> encoding.encoding = b'utf-8' >>> t = b'1234567890' >>> bprint(trim(t, 12, ellipsis=ellipsis)) 1234567890 >>> bprint(trim(t, 10, ellipsis=ellipsis)) 1234567890 >>> bprint(trim(t, 8, ellipsis=ellipsis)) 12345+++ >>> bprint(trim(t, 8, ellipsis=ellipsis, leftside=True)) +++67890 >>> bprint(trim(t, 8)) 12345678 >>> bprint(trim(t, 8, leftside=True)) 34567890 >>> bprint(trim(t, 3, ellipsis=ellipsis)) +++ >>> bprint(trim(t, 1, ellipsis=ellipsis)) + >>> u = u'\u3042\u3044\u3046\u3048\u304a' # 2 x 5 = 10 columns >>> t = u.encode(pycompat.sysstr(encoding.encoding)) >>> bprint(trim(t, 12, ellipsis=ellipsis)) \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88\xe3\x81\x8a >>> bprint(trim(t, 10, ellipsis=ellipsis)) \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88\xe3\x81\x8a >>> bprint(trim(t, 8, ellipsis=ellipsis)) \xe3\x81\x82\xe3\x81\x84+++ >>> bprint(trim(t, 8, ellipsis=ellipsis, leftside=True)) +++\xe3\x81\x88\xe3\x81\x8a >>> bprint(trim(t, 5)) \xe3\x81\x82\xe3\x81\x84 >>> bprint(trim(t, 5, leftside=True)) \xe3\x81\x88\xe3\x81\x8a >>> bprint(trim(t, 4, ellipsis=ellipsis)) +++ >>> bprint(trim(t, 4, ellipsis=ellipsis, leftside=True)) +++ >>> t = bin(b'112233445566778899aa') # invalid byte sequence >>> bprint(trim(t, 12, ellipsis=ellipsis)) \x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa >>> bprint(trim(t, 10, ellipsis=ellipsis)) \x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa >>> bprint(trim(t, 8, ellipsis=ellipsis)) \x11\x22\x33\x44\x55+++ >>> bprint(trim(t, 8, ellipsis=ellipsis, leftside=True)) +++\x66\x77\x88\x99\xaa >>> bprint(trim(t, 8)) \x11\x22\x33\x44\x55\x66\x77\x88 >>> bprint(trim(t, 8, leftside=True)) \x33\x44\x55\x66\x77\x88\x99\xaa >>> bprint(trim(t, 3, ellipsis=ellipsis)) +++ >>> bprint(trim(t, 1, ellipsis=ellipsis)) + """ try: u = s.decode(_sysstr(encoding)) except UnicodeDecodeError: if len(s) <= width: # trimming is not needed return s width -= len(ellipsis) if width <= 0: # no enough room even for ellipsis return ellipsis[:width + len(ellipsis)] if leftside: return ellipsis + s[-width:] return s[:width] + ellipsis if ucolwidth(u) <= width: # trimming is not needed return s width -= len(ellipsis) if width <= 0: # no enough room even for ellipsis return ellipsis[:width + len(ellipsis)] if leftside: uslice = lambda i: u[i:] concat = lambda s: ellipsis + s else: uslice = lambda i: u[:-i] concat = lambda s: s + ellipsis for i in pycompat.xrange(1, len(u)): usub = uslice(i) if ucolwidth(usub) <= width: return concat(usub.encode(_sysstr(encoding))) return ellipsis # no enough room for multi-column characters def lower(s): "best-effort encoding-aware case-folding of local string s" try: return asciilower(s) except UnicodeDecodeError: pass try: if isinstance(s, localstr): u = s._utf8.decode("utf-8") else: u = s.decode(_sysstr(encoding), _sysstr(encodingmode)) lu = u.lower() if u == lu: return s # preserve localstring return lu.encode(_sysstr(encoding)) except UnicodeError: return s.lower() # we don't know how to fold this except in ASCII except LookupError as k: raise error.Abort(k, hint="please check your locale settings") def upper(s): "best-effort encoding-aware case-folding of local string s" try: return asciiupper(s) except UnicodeDecodeError: return upperfallback(s) def upperfallback(s): try: if isinstance(s, localstr): u = s._utf8.decode("utf-8") else: u = s.decode(_sysstr(encoding), _sysstr(encodingmode)) uu = u.upper() if u == uu: return s # preserve localstring return uu.encode(_sysstr(encoding)) except UnicodeError: return s.upper() # we don't know how to fold this except in ASCII except LookupError as k: raise error.Abort(k, hint="please check your locale settings") class normcasespecs(object): '''what a platform's normcase does to ASCII strings This is specified per platform, and should be consistent with what normcase on that platform actually does. lower: normcase lowercases ASCII strings upper: normcase uppercases ASCII strings other: the fallback function should always be called This should be kept in sync with normcase_spec in util.h.''' lower = -1 upper = 1 other = 0 def jsonescape(s, paranoid=False): '''returns a string suitable for JSON JSON is problematic for us because it doesn't support non-Unicode bytes. To deal with this, we take the following approach: - localstr/safelocalstr objects are converted back to UTF-8 - valid UTF-8/ASCII strings are passed as-is - other strings are converted to UTF-8b surrogate encoding - apply JSON-specified string escaping (escapes are doubled in these tests) >>> jsonescape(b'this is a test') 'this is a test' >>> jsonescape(b'escape characters: \\0 \\x0b \\x7f') 'escape characters: \\\\u0000 \\\\u000b \\\\u007f' >>> jsonescape(b'escape characters: \\b \\t \\n \\f \\r \\" \\\\') 'escape characters: \\\\b \\\\t \\\\n \\\\f \\\\r \\\\" \\\\\\\\' >>> jsonescape(b'a weird byte: \\xdd') 'a weird byte: \\xed\\xb3\\x9d' >>> jsonescape(b'utf-8: caf\\xc3\\xa9') 'utf-8: caf\\xc3\\xa9' >>> jsonescape(b'') '' If paranoid, non-ascii and common troublesome characters are also escaped. This is suitable for web output. >>> s = b'escape characters: \\0 \\x0b \\x7f' >>> assert jsonescape(s) == jsonescape(s, paranoid=True) >>> s = b'escape characters: \\b \\t \\n \\f \\r \\" \\\\' >>> assert jsonescape(s) == jsonescape(s, paranoid=True) >>> jsonescape(b'escape boundary: \\x7e \\x7f \\xc2\\x80', paranoid=True) 'escape boundary: ~ \\\\u007f \\\\u0080' >>> jsonescape(b'a weird byte: \\xdd', paranoid=True) 'a weird byte: \\\\udcdd' >>> jsonescape(b'utf-8: caf\\xc3\\xa9', paranoid=True) 'utf-8: caf\\\\u00e9' >>> jsonescape(b'non-BMP: \\xf0\\x9d\\x84\\x9e', paranoid=True) 'non-BMP: \\\\ud834\\\\udd1e' >>> jsonescape(b'<foo@example.org>', paranoid=True) '\\\\u003cfoo@example.org\\\\u003e' ''' u8chars = toutf8b(s) try: return _jsonescapeu8fast(u8chars, paranoid) except ValueError: pass return charencodepure.jsonescapeu8fallback(u8chars, paranoid) # We need to decode/encode U+DCxx codes transparently since invalid UTF-8 # bytes are mapped to that range. if pycompat.ispy3: _utf8strict = r'surrogatepass' else: _utf8strict = r'strict' _utf8len = [0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 4] def getutf8char(s, pos): '''get the next full utf-8 character in the given string, starting at pos Raises a UnicodeError if the given location does not start a valid utf-8 character. ''' # find how many bytes to attempt decoding from first nibble l = _utf8len[ord(s[pos:pos + 1]) >> 4] if not l: # ascii return s[pos:pos + 1] c = s[pos:pos + l] # validate with attempted decode c.decode("utf-8", _utf8strict) return c def toutf8b(s): '''convert a local, possibly-binary string into UTF-8b This is intended as a generic method to preserve data when working with schemes like JSON and XML that have no provision for arbitrary byte strings. As Mercurial often doesn't know what encoding data is in, we use so-called UTF-8b. If a string is already valid UTF-8 (or ASCII), it passes unmodified. Otherwise, unsupported bytes are mapped to UTF-16 surrogate range, uDC00-uDCFF. Principles of operation: - ASCII and UTF-8 data successfully round-trips and is understood by Unicode-oriented clients - filenames and file contents in arbitrary other encodings can have be round-tripped or recovered by clueful clients - local strings that have a cached known UTF-8 encoding (aka localstr) get sent as UTF-8 so Unicode-oriented clients get the Unicode data they want - non-lossy local strings (aka safelocalstr) get sent as UTF-8 as well - because we must preserve UTF-8 bytestring in places such as filenames, metadata can't be roundtripped without help (Note: "UTF-8b" often refers to decoding a mix of valid UTF-8 and arbitrary bytes into an internal Unicode format that can be re-encoded back into the original. Here we are exposing the internal surrogate encoding as a UTF-8 string.) ''' if isinstance(s, localstr): # assume that the original UTF-8 sequence would never contain # invalid characters in U+DCxx range return s._utf8 elif isinstance(s, safelocalstr): # already verified that s is non-lossy in legacy encoding, which # shouldn't contain characters in U+DCxx range return fromlocal(s) elif isasciistr(s): return s if "\xed" not in s: try: s.decode('utf-8', _utf8strict) return s except UnicodeDecodeError: pass s = pycompat.bytestr(s) r = "" pos = 0 l = len(s) while pos < l: try: c = getutf8char(s, pos) if "\xed\xb0\x80" <= c <= "\xed\xb3\xbf": # have to re-escape existing U+DCxx characters c = unichr(0xdc00 + ord(s[pos])).encode('utf-8', _utf8strict) pos += 1 else: pos += len(c) except UnicodeDecodeError: c = unichr(0xdc00 + ord(s[pos])).encode('utf-8', _utf8strict) pos += 1 r += c return r def fromutf8b(s): '''Given a UTF-8b string, return a local, possibly-binary string. return the original binary string. This is a round-trip process for strings like filenames, but metadata that's was passed through tolocal will remain in UTF-8. >>> roundtrip = lambda x: fromutf8b(toutf8b(x)) == x >>> m = b"\\xc3\\xa9\\x99abcd" >>> toutf8b(m) '\\xc3\\xa9\\xed\\xb2\\x99abcd' >>> roundtrip(m) True >>> roundtrip(b"\\xc2\\xc2\\x80") True >>> roundtrip(b"\\xef\\xbf\\xbd") True >>> roundtrip(b"\\xef\\xef\\xbf\\xbd") True >>> roundtrip(b"\\xf1\\x80\\x80\\x80\\x80") True ''' if isasciistr(s): return s # fast path - look for uDxxx prefixes in s if "\xed" not in s: return s # We could do this with the unicode type but some Python builds # use UTF-16 internally (issue5031) which causes non-BMP code # points to be escaped. Instead, we use our handy getutf8char # helper again to walk the string without "decoding" it. s = pycompat.bytestr(s) r = "" pos = 0 l = len(s) while pos < l: c = getutf8char(s, pos) pos += len(c) # unescape U+DCxx characters if "\xed\xb0\x80" <= c <= "\xed\xb3\xbf": c = pycompat.bytechr(ord(c.decode("utf-8", _utf8strict)) & 0xff) r += c return r