mercurial/templater.py

copies: iterate over children directly (instead of parents)

Before this change we would gather all parent → child edges and iterate on
all parent, gathering copy information for children and aggregating them from
there.

They are not strict requirement for edges to be processed in that specific
order. We could also simply iterate over all "children" revision and aggregate
data from both parents at the same time. This patch does that.

It make various things simpler:

 * since both parents are processed at the same time, we no longer need to
   cache data for merge (see next changeset for details),

 * we no longer need nested loop to process data,

 * we no longer need to store partial merge data for a rev from distinct loop
   interaction to another when processing merges,

 * we no longer need to build a full parent -> children mapping (we only rely on
   a simpler "parent -> number of children" map (for memory efficiency),

 * the data access pattern is now simpler (from lower revisions to higher
   revisions) and entirely predicable. That predictability open the way to
   prefetching and parallel processing.

So that new iterations order requires simpler code and open the way to
interesting optimisation.

The effect on performance is quite good. In the worse case, we don't see any
significant negative impact. And in the best case, the reduction of roundtrip
to Python provide us with a significant speed. Some example below:

Repo            Case                                  Source-Rev   Dest-Rev      # of revisions  old time    new time      Difference    Factor    time per rev
---------------------------------------------------------------------------------------------------------------------------------------------------------------
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c :  34414 revs,   0.962867 s,   0.502584 s,  -0.460283 s, × 0.5220,    14 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :   8598 revs,   0.110717 s,   0.076323 s,  -0.034394 s, × 0.6894,     8 µs/rev



# full comparison between the previous changeset and this one

Repo            Case                                  Source-Rev   Dest-Rev      # of revisions  old time    new time      Difference    Factor    time per rev
---------------------------------------------------------------------------------------------------------------------------------------------------------------
mercurial       x_revs_x_added_0_copies               ad6b123de1c7 39cfcef4f463 :      1 revs,   0.000048 s,   0.000041 s,  -0.000007 s, × 0.8542,    41 µs/rev
mercurial       x_revs_x_added_x_copies               2b1c78674230 0c1d10351869 :      6 revs,   0.000153 s,   0.000102 s,  -0.000051 s, × 0.6667,    17 µs/rev
mercurial       x000_revs_x000_added_x_copies         81f8ff2a9bf2 dd3267698d84 :   1032 revs,   0.004209 s,   0.004254 s,  +0.000045 s, × 1.0107,     4 µs/rev
pypy            x_revs_x_added_0_copies               aed021ee8ae8 099ed31b181b :      9 revs,   0.000203 s,   0.000282 s,  +0.000079 s, × 1.3892,    31 µs/rev
pypy            x_revs_x000_added_0_copies            4aa4e1f8e19a 359343b9ac0e :      1 revs,   0.000059 s,   0.000048 s,  -0.000011 s, × 0.8136,    48 µs/rev
pypy            x_revs_x_added_x_copies               ac52eb7bbbb0 72e022663155 :      7 revs,   0.000194 s,   0.000211 s,  +0.000017 s, × 1.0876,    30 µs/rev
pypy            x_revs_x00_added_x_copies             c3b14617fbd7 ace7255d9a26 :      1 revs,   0.000380 s,   0.000375 s,  -0.000005 s, × 0.9868,   375 µs/rev
pypy            x_revs_x000_added_x000_copies         df6f7a526b60 a83dc6a2d56f :      6 revs,   0.010588 s,   0.010574 s,  -0.000014 s, × 0.9987,  1762 µs/rev
pypy            x000_revs_xx00_added_0_copies         89a76aede314 2f22446ff07e :   4785 revs,   0.048961 s,   0.049974 s,  +0.001013 s, × 1.0207,    10 µs/rev
pypy            x000_revs_x000_added_x_copies         8a3b5bfd266e 2c68e87c3efe :   6780 revs,   0.083612 s,   0.084300 s,  +0.000688 s, × 1.0082,    12 µs/rev
pypy            x000_revs_x000_added_x000_copies      89a76aede314 7b3dda341c84 :   5441 revs,   0.058579 s,   0.060128 s,  +0.001549 s, × 1.0264,    11 µs/rev
pypy            x0000_revs_x_added_0_copies           d1defd0dc478 c9cb1334cc78 :  43645 revs,   0.736783 s,   0.686542 s,  -0.050241 s, × 0.9318,    15 µs/rev
pypy            x0000_revs_xx000_added_0_copies       bf2c629d0071 4ffed77c095c :      2 revs,   0.022050 s,   0.009277 s,  -0.012773 s, × 0.4207,  4638 µs/rev
pypy            x0000_revs_xx000_added_x000_copies    08ea3258278e d9fa043f30c0 :  11316 revs,   0.120800 s,   0.114733 s,  -0.006067 s, × 0.9498,    10 µs/rev
netbeans        x_revs_x_added_0_copies               fb0955ffcbcd a01e9239f9e7 :      2 revs,   0.000140 s,   0.000081 s,  -0.000059 s, × 0.5786,    40 µs/rev
netbeans        x_revs_x000_added_0_copies            6f360122949f 20eb231cc7d0 :      2 revs,   0.000114 s,   0.000107 s,  -0.000007 s, × 0.9386,    53 µs/rev
netbeans        x_revs_x_added_x_copies               1ada3faf6fb6 5a39d12eecf4 :      3 revs,   0.000224 s,   0.000173 s,  -0.000051 s, × 0.7723,    57 µs/rev
netbeans        x_revs_x00_added_x_copies             35be93ba1e2c 9eec5e90c05f :      9 revs,   0.000723 s,   0.000698 s,  -0.000025 s, × 0.9654,    77 µs/rev
netbeans        x000_revs_xx00_added_0_copies         eac3045b4fdd 51d4ae7f1290 :   1421 revs,   0.009665 s,   0.009248 s,  -0.000417 s, × 0.9569,     6 µs/rev
netbeans        x000_revs_x000_added_x_copies         e2063d266acd 6081d72689dc :   1533 revs,   0.014820 s,   0.015446 s,  +0.000626 s, × 1.0422,    10 µs/rev
netbeans        x000_revs_x000_added_x000_copies      ff453e9fee32 411350406ec2 :   5750 revs,   0.076049 s,   0.074373 s,  -0.001676 s, × 0.9780,    12 µs/rev
netbeans        x0000_revs_xx000_added_x000_copies    588c2d1ced70 1aad62e59ddd :  66949 revs,   0.683603 s,   0.639870 s,  -0.043733 s, × 0.9360,     9 µs/rev
mozilla-central x_revs_x_added_0_copies               3697f962bb7b 7015fcdd43a2 :      2 revs,   0.000161 s,   0.000088 s,  -0.000073 s, × 0.5466,    44 µs/rev
mozilla-central x_revs_x000_added_0_copies            dd390860c6c9 40d0c5bed75d :      8 revs,   0.000234 s,   0.000199 s,  -0.000035 s, × 0.8504,    24 µs/rev
mozilla-central x_revs_x_added_x_copies               8d198483ae3b 14207ffc2b2f :      9 revs,   0.000247 s,   0.000171 s,  -0.000076 s, × 0.6923,    19 µs/rev
mozilla-central x_revs_x00_added_x_copies             98cbc58cc6bc 446a150332c3 :      7 revs,   0.000630 s,   0.000592 s,  -0.000038 s, × 0.9397,    84 µs/rev
mozilla-central x_revs_x000_added_x000_copies         3c684b4b8f68 0a5e72d1b479 :      3 revs,   0.003286 s,   0.003151 s,  -0.000135 s, × 0.9589,  1050 µs/rev
mozilla-central x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.062441 s,   0.061612 s,  -0.000829 s, × 0.9867, 10268 µs/rev
mozilla-central x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.005423 s,   0.005381 s,  -0.000042 s, × 0.9923,     3 µs/rev
mozilla-central x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :     41 revs,   0.005919 s,   0.003742 s,  -0.002177 s, × 0.6322,    91 µs/rev
mozilla-central x000_revs_x000_added_x000_copies      7c97034feb78 4407bd0c6330 :   7839 revs,   0.062597 s,   0.061983 s,  -0.000614 s, × 0.9902,     7 µs/rev
mozilla-central x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :    615 revs,   0.043551 s,   0.019861 s,  -0.023690 s, × 0.4560,    32 µs/rev
mozilla-central x0000_revs_xx000_added_x000_copies    f78c615a656c 96a38b690156 :  30263 revs,   0.192475 s,   0.188101 s,  -0.004374 s, × 0.9773,     6 µs/rev
mozilla-central x00000_revs_x0000_added_x0000_copies  6832ae71433c 4c222a1d9a00 : 153721 revs,   1.955575 s,   1.806696 s,  -0.148879 s, × 0.9239,    11 µs/rev
mozilla-central x00000_revs_x00000_added_x000_copies  76caed42cf7c 1daa622bbe42 : 204976 revs,   2.886501 s,   2.682987 s,  -0.203514 s, × 0.9295,    13 µs/rev
mozilla-try     x_revs_x_added_0_copies               aaf6dde0deb8 9790f499805a :      2 revs,   0.001181 s,   0.000852 s,  -0.000329 s, × 0.7214,   426 µs/rev
mozilla-try     x_revs_x000_added_0_copies            d8d0222927b4 5bb8ce8c7450 :      2 revs,   0.001189 s,   0.000859 s,  -0.000330 s, × 0.7225,   429 µs/rev
mozilla-try     x_revs_x_added_x_copies               092fcca11bdb 936255a0384a :      4 revs,   0.000563 s,   0.000150 s,  -0.000413 s, × 0.2664,    37 µs/rev
mozilla-try     x_revs_x00_added_x_copies             b53d2fadbdb5 017afae788ec :      2 revs,   0.001548 s,   0.001158 s,  -0.000390 s, × 0.7481,   579 µs/rev
mozilla-try     x_revs_x000_added_x000_copies         20408ad61ce5 6f0ee96e21ad :      1 revs,   0.027782 s,   0.027240 s,  -0.000542 s, × 0.9805, 27240 µs/rev
mozilla-try     x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.062781 s,   0.062824 s,  +0.000043 s, × 1.0007, 10470 µs/rev
mozilla-try     x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.005778 s,   0.005463 s,  -0.000315 s, × 0.9455,     3 µs/rev
mozilla-try     x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :     41 revs,   0.006192 s,   0.004238 s,  -0.001954 s, × 0.6844,   103 µs/rev
mozilla-try     x000_revs_x000_added_x000_copies      1346fd0130e4 4c65cbdabc1f :   6657 revs,   0.065391 s,   0.064113 s,  -0.001278 s, × 0.9805,     9 µs/rev
mozilla-try     x0000_revs_x_added_0_copies           63519bfd42ee a36a2a865d92 :  40314 revs,   0.317216 s,   0.294063 s,  -0.023153 s, × 0.9270,     7 µs/rev
mozilla-try     x0000_revs_x_added_x_copies           9fe69ff0762d bcabf2a78927 :  38690 revs,   0.303119 s,   0.281493 s,  -0.021626 s, × 0.9287,     7 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :   8598 revs,   0.110717 s,   0.076323 s,  -0.034394 s, × 0.6894,     8 µs/rev
mozilla-try     x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :    615 revs,   0.045739 s,   0.020390 s,  -0.025349 s, × 0.4458,    33 µs/rev
mozilla-try     x0000_revs_xx000_added_x000_copies    89294cd501d9 7ccb2fc7ccb5 :  97052 revs,   3.098021 s,   3.023879 s,  -0.074142 s, × 0.9761,    31 µs/rev
mozilla-try     x0000_revs_x0000_added_x0000_copies   e928c65095ed e951f4ad123a :  52031 revs,   0.771480 s,   0.735549 s,  -0.035931 s, × 0.9534,    14 µs/rev
mozilla-try     x00000_revs_x_added_0_copies          6a320851d377 1ebb79acd503 : 363753 revs,  18.813422 s,  18.568900 s,  -0.244522 s, × 0.9870,    51 µs/rev
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c :  34414 revs,   0.962867 s,   0.502584 s,  -0.460283 s, × 0.5220,    14 µs/rev
mozilla-try     x00000_revs_x_added_x_copies          5173c4b6f97c 95d83ee7242d : 362229 revs,  18.684923 s,  18.356645 s,  -0.328278 s, × 0.9824,    50 µs/rev
mozilla-try     x00000_revs_x000_added_x_copies       9126823d0e9c ca82787bb23c : 359344 revs,  18.296305 s,  18.250393 s,  -0.045912 s, × 0.9975,    50 µs/rev
mozilla-try     x00000_revs_x0000_added_x0000_copies  8d3fafa80d4b eb884023b810 : 192665 revs,   3.061887 s,   2.792459 s,  -0.269428 s, × 0.9120,    14 µs/rev
mozilla-try     x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 228985 revs, 103.869641 s, 107.697264 s,  +3.827623 s, × 1.0369,   470 µs/rev
mozilla-try     x00000_revs_x00000_added_x000_copies  9b2a99adc05e 8e29777b48e6 : 382065 revs,  64.262957 s,  63.961040 s,  -0.301917 s, × 0.9953,   167 µs/rev

Differential Revision: https://phab.mercurial-scm.org/D9422

# templater.py - template expansion for output
#
# Copyright 2005, 2006 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

"""Slightly complicated template engine for commands and hgweb

This module provides low-level interface to the template engine. See the
formatter and cmdutil modules if you are looking for high-level functions
such as ``cmdutil.rendertemplate(ctx, tmpl)``.

Internal Data Types
-------------------

Template keywords and functions take a dictionary of current symbols and
resources (a "mapping") and return result. Inputs and outputs must be one
of the following data types:

bytes
    a byte string, which is generally a human-readable text in local encoding.

generator
    a lazily-evaluated byte string, which is a possibly nested generator of
    values of any printable types, and  will be folded by ``stringify()``
    or ``flatten()``.

None
    sometimes represents an empty value, which can be stringified to ''.

True, False, int, float
    can be stringified as such.

wrappedbytes, wrappedvalue
    a wrapper for the above printable types.

date
    represents a (unixtime, offset) tuple.

hybrid
    represents a list/dict of printable values, which can also be converted
    to mappings by % operator.

hybriditem
    represents a scalar printable value, also supports % operator.

revslist
    represents a list of revision numbers.

mappinggenerator, mappinglist
    represents mappings (i.e. a list of dicts), which may have default
    output format.

mappingdict
    represents a single mapping (i.e. a dict), which may have default output
    format.

mappingnone
    represents None of Optional[mappable], which will be mapped to an empty
    string by % operation.

mappedgenerator
    a lazily-evaluated list of byte strings, which is e.g. a result of %
    operation.
"""

from __future__ import absolute_import, print_function

import abc
import os

from .i18n import _
from .pycompat import getattr
from . import (
    config,
    encoding,
    error,
    parser,
    pycompat,
    templatefilters,
    templatefuncs,
    templateutil,
    util,
)
from .utils import (
    resourceutil,
    stringutil,
)

# template parsing

elements = {
    # token-type: binding-strength, primary, prefix, infix, suffix
    b"(": (20, None, (b"group", 1, b")"), (b"func", 1, b")"), None),
    b".": (18, None, None, (b".", 18), None),
    b"%": (15, None, None, (b"%", 15), None),
    b"|": (15, None, None, (b"|", 15), None),
    b"*": (5, None, None, (b"*", 5), None),
    b"/": (5, None, None, (b"/", 5), None),
    b"+": (4, None, None, (b"+", 4), None),
    b"-": (4, None, (b"negate", 19), (b"-", 4), None),
    b"=": (3, None, None, (b"keyvalue", 3), None),
    b",": (2, None, None, (b"list", 2), None),
    b")": (0, None, None, None, None),
    b"integer": (0, b"integer", None, None, None),
    b"symbol": (0, b"symbol", None, None, None),
    b"string": (0, b"string", None, None, None),
    b"template": (0, b"template", None, None, None),
    b"end": (0, None, None, None, None),
}


def tokenize(program, start, end, term=None):
    """Parse a template expression into a stream of tokens, which must end
    with term if specified"""
    pos = start
    program = pycompat.bytestr(program)
    while pos < end:
        c = program[pos]
        if c.isspace():  # skip inter-token whitespace
            pass
        elif c in b"(=,).%|+-*/":  # handle simple operators
            yield (c, None, pos)
        elif c in b'"\'':  # handle quoted templates
            s = pos + 1
            data, pos = _parsetemplate(program, s, end, c)
            yield (b'template', data, s)
            pos -= 1
        elif c == b'r' and program[pos : pos + 2] in (b"r'", b'r"'):
            # handle quoted strings
            c = program[pos + 1]
            s = pos = pos + 2
            while pos < end:  # find closing quote
                d = program[pos]
                if d == b'\\':  # skip over escaped characters
                    pos += 2
                    continue
                if d == c:
                    yield (b'string', program[s:pos], s)
                    break
                pos += 1
            else:
                raise error.ParseError(_(b"unterminated string"), s)
        elif c.isdigit():
            s = pos
            while pos < end:
                d = program[pos]
                if not d.isdigit():
                    break
                pos += 1
            yield (b'integer', program[s:pos], s)
            pos -= 1
        elif (
            c == b'\\'
            and program[pos : pos + 2] in (br"\'", br'\"')
            or c == b'r'
            and program[pos : pos + 3] in (br"r\'", br'r\"')
        ):
            # handle escaped quoted strings for compatibility with 2.9.2-3.4,
            # where some of nested templates were preprocessed as strings and
            # then compiled. therefore, \"...\" was allowed. (issue4733)
            #
            # processing flow of _evalifliteral() at 5ab28a2e9962:
            # outer template string    -> stringify()  -> compiletemplate()
            # ------------------------    ------------    ------------------
            # {f("\\\\ {g(\"\\\"\")}"}    \\ {g("\"")}    [r'\\', {g("\"")}]
            #             ~~~~~~~~
            #             escaped quoted string
            if c == b'r':
                pos += 1
                token = b'string'
            else:
                token = b'template'
            quote = program[pos : pos + 2]
            s = pos = pos + 2
            while pos < end:  # find closing escaped quote
                if program.startswith(b'\\\\\\', pos, end):
                    pos += 4  # skip over double escaped characters
                    continue
                if program.startswith(quote, pos, end):
                    # interpret as if it were a part of an outer string
                    data = parser.unescapestr(program[s:pos])
                    if token == b'template':
                        data = _parsetemplate(data, 0, len(data))[0]
                    yield (token, data, s)
                    pos += 1
                    break
                pos += 1
            else:
                raise error.ParseError(_(b"unterminated string"), s)
        elif c.isalnum() or c in b'_':
            s = pos
            pos += 1
            while pos < end:  # find end of symbol
                d = program[pos]
                if not (d.isalnum() or d == b"_"):
                    break
                pos += 1
            sym = program[s:pos]
            yield (b'symbol', sym, s)
            pos -= 1
        elif c == term:
            yield (b'end', None, pos)
            return
        else:
            raise error.ParseError(_(b"syntax error"), pos)
        pos += 1
    if term:
        raise error.ParseError(_(b"unterminated template expansion"), start)
    yield (b'end', None, pos)


def _parsetemplate(tmpl, start, stop, quote=b''):
    r"""
    >>> _parsetemplate(b'foo{bar}"baz', 0, 12)
    ([('string', 'foo'), ('symbol', 'bar'), ('string', '"baz')], 12)
    >>> _parsetemplate(b'foo{bar}"baz', 0, 12, quote=b'"')
    ([('string', 'foo'), ('symbol', 'bar')], 9)
    >>> _parsetemplate(b'foo"{bar}', 0, 9, quote=b'"')
    ([('string', 'foo')], 4)
    >>> _parsetemplate(br'foo\"bar"baz', 0, 12, quote=b'"')
    ([('string', 'foo"'), ('string', 'bar')], 9)
    >>> _parsetemplate(br'foo\\"bar', 0, 10, quote=b'"')
    ([('string', 'foo\\')], 6)
    """
    parsed = []
    for typ, val, pos in _scantemplate(tmpl, start, stop, quote):
        if typ == b'string':
            parsed.append((typ, val))
        elif typ == b'template':
            parsed.append(val)
        elif typ == b'end':
            return parsed, pos
        else:
            raise error.ProgrammingError(b'unexpected type: %s' % typ)
    raise error.ProgrammingError(b'unterminated scanning of template')


def scantemplate(tmpl, raw=False):
    r"""Scan (type, start, end) positions of outermost elements in template

    If raw=True, a backslash is not taken as an escape character just like
    r'' string in Python. Note that this is different from r'' literal in
    template in that no template fragment can appear in r'', e.g. r'{foo}'
    is a literal '{foo}', but ('{foo}', raw=True) is a template expression
    'foo'.

    >>> list(scantemplate(b'foo{bar}"baz'))
    [('string', 0, 3), ('template', 3, 8), ('string', 8, 12)]
    >>> list(scantemplate(b'outer{"inner"}outer'))
    [('string', 0, 5), ('template', 5, 14), ('string', 14, 19)]
    >>> list(scantemplate(b'foo\\{escaped}'))
    [('string', 0, 5), ('string', 5, 13)]
    >>> list(scantemplate(b'foo\\{escaped}', raw=True))
    [('string', 0, 4), ('template', 4, 13)]
    """
    last = None
    for typ, val, pos in _scantemplate(tmpl, 0, len(tmpl), raw=raw):
        if last:
            yield last + (pos,)
        if typ == b'end':
            return
        else:
            last = (typ, pos)
    raise error.ProgrammingError(b'unterminated scanning of template')


def _scantemplate(tmpl, start, stop, quote=b'', raw=False):
    """Parse template string into chunks of strings and template expressions"""
    sepchars = b'{' + quote
    unescape = [parser.unescapestr, pycompat.identity][raw]
    pos = start
    p = parser.parser(elements)
    try:
        while pos < stop:
            n = min(
                (tmpl.find(c, pos, stop) for c in pycompat.bytestr(sepchars)),
                key=lambda n: (n < 0, n),
            )
            if n < 0:
                yield (b'string', unescape(tmpl[pos:stop]), pos)
                pos = stop
                break
            c = tmpl[n : n + 1]
            bs = 0  # count leading backslashes
            if not raw:
                bs = (n - pos) - len(tmpl[pos:n].rstrip(b'\\'))
            if bs % 2 == 1:
                # escaped (e.g. '\{', '\\\{', but not '\\{')
                yield (b'string', unescape(tmpl[pos : n - 1]) + c, pos)
                pos = n + 1
                continue
            if n > pos:
                yield (b'string', unescape(tmpl[pos:n]), pos)
            if c == quote:
                yield (b'end', None, n + 1)
                return

            parseres, pos = p.parse(tokenize(tmpl, n + 1, stop, b'}'))
            if not tmpl.startswith(b'}', pos):
                raise error.ParseError(_(b"invalid token"), pos)
            yield (b'template', parseres, n)
            pos += 1

        if quote:
            raise error.ParseError(_(b"unterminated string"), start)
    except error.ParseError as inst:
        _addparseerrorhint(inst, tmpl)
        raise
    yield (b'end', None, pos)


def _addparseerrorhint(inst, tmpl):
    if inst.location is None:
        return
    loc = inst.location
    # Offset the caret location by the number of newlines before the
    # location of the error, since we will replace one-char newlines
    # with the two-char literal r'\n'.
    offset = tmpl[:loc].count(b'\n')
    tmpl = tmpl.replace(b'\n', br'\n')
    # We want the caret to point to the place in the template that
    # failed to parse, but in a hint we get a open paren at the
    # start. Therefore, we print "loc + 1" spaces (instead of "loc")
    # to line up the caret with the location of the error.
    inst.hint = tmpl + b'\n' + b' ' * (loc + 1 + offset) + b'^ ' + _(b'here')


def _unnesttemplatelist(tree):
    """Expand list of templates to node tuple

    >>> def f(tree):
    ...     print(pycompat.sysstr(prettyformat(_unnesttemplatelist(tree))))
    >>> f((b'template', []))
    (string '')
    >>> f((b'template', [(b'string', b'foo')]))
    (string 'foo')
    >>> f((b'template', [(b'string', b'foo'), (b'symbol', b'rev')]))
    (template
      (string 'foo')
      (symbol 'rev'))
    >>> f((b'template', [(b'symbol', b'rev')]))  # template(rev) -> str
    (template
      (symbol 'rev'))
    >>> f((b'template', [(b'template', [(b'string', b'foo')])]))
    (string 'foo')
    """
    if not isinstance(tree, tuple):
        return tree
    op = tree[0]
    if op != b'template':
        return (op,) + tuple(_unnesttemplatelist(x) for x in tree[1:])

    assert len(tree) == 2
    xs = tuple(_unnesttemplatelist(x) for x in tree[1])
    if not xs:
        return (b'string', b'')  # empty template ""
    elif len(xs) == 1 and xs[0][0] == b'string':
        return xs[0]  # fast path for string with no template fragment "x"
    else:
        return (op,) + xs


def parse(tmpl):
    """Parse template string into tree"""
    parsed, pos = _parsetemplate(tmpl, 0, len(tmpl))
    assert pos == len(tmpl), b'unquoted template should be consumed'
    return _unnesttemplatelist((b'template', parsed))


def parseexpr(expr):
    """Parse a template expression into tree

    >>> parseexpr(b'"foo"')
    ('string', 'foo')
    >>> parseexpr(b'foo(bar)')
    ('func', ('symbol', 'foo'), ('symbol', 'bar'))
    >>> from . import error
    >>> from . import pycompat
    >>> try:
    ...   parseexpr(b'foo(')
    ... except error.ParseError as e:
    ...   pycompat.sysstr(e.message)
    ...   e.location
    'not a prefix: end'
    4
    >>> try:
    ...   parseexpr(b'"foo" "bar"')
    ... except error.ParseError as e:
    ...   pycompat.sysstr(e.message)
    ...   e.location
    'invalid token'
    7
    """
    try:
        return _parseexpr(expr)
    except error.ParseError as inst:
        _addparseerrorhint(inst, expr)
        raise


def _parseexpr(expr):
    p = parser.parser(elements)
    tree, pos = p.parse(tokenize(expr, 0, len(expr)))
    if pos != len(expr):
        raise error.ParseError(_(b'invalid token'), pos)
    return _unnesttemplatelist(tree)


def prettyformat(tree):
    return parser.prettyformat(tree, (b'integer', b'string', b'symbol'))


def compileexp(exp, context, curmethods):
    """Compile parsed template tree to (func, data) pair"""
    if not exp:
        raise error.ParseError(_(b"missing argument"))
    t = exp[0]
    return curmethods[t](exp, context)


# template evaluation


def getsymbol(exp):
    if exp[0] == b'symbol':
        return exp[1]
    raise error.ParseError(_(b"expected a symbol, got '%s'") % exp[0])


def getlist(x):
    if not x:
        return []
    if x[0] == b'list':
        return getlist(x[1]) + [x[2]]
    return [x]


def gettemplate(exp, context):
    """Compile given template tree or load named template from map file;
    returns (func, data) pair"""
    if exp[0] in (b'template', b'string'):
        return compileexp(exp, context, methods)
    if exp[0] == b'symbol':
        # unlike runsymbol(), here 'symbol' is always taken as template name
        # even if it exists in mapping. this allows us to override mapping
        # by web templates, e.g. 'changelogtag' is redefined in map file.
        return context._load(exp[1])
    raise error.ParseError(_(b"expected template specifier"))


def _runrecursivesymbol(context, mapping, key):
    raise error.InputError(_(b"recursive reference '%s' in template") % key)


def buildtemplate(exp, context):
    ctmpl = [compileexp(e, context, methods) for e in exp[1:]]
    return (templateutil.runtemplate, ctmpl)


def buildfilter(exp, context):
    n = getsymbol(exp[2])
    if n in context._filters:
        filt = context._filters[n]
        arg = compileexp(exp[1], context, methods)
        return (templateutil.runfilter, (arg, filt))
    if n in context._funcs:
        f = context._funcs[n]
        args = _buildfuncargs(exp[1], context, methods, n, f._argspec)
        return (f, args)
    raise error.ParseError(_(b"unknown function '%s'") % n)


def buildmap(exp, context):
    darg = compileexp(exp[1], context, methods)
    targ = gettemplate(exp[2], context)
    return (templateutil.runmap, (darg, targ))


def buildmember(exp, context):
    darg = compileexp(exp[1], context, methods)
    memb = getsymbol(exp[2])
    return (templateutil.runmember, (darg, memb))


def buildnegate(exp, context):
    arg = compileexp(exp[1], context, exprmethods)
    return (templateutil.runnegate, arg)


def buildarithmetic(exp, context, func):
    left = compileexp(exp[1], context, exprmethods)
    right = compileexp(exp[2], context, exprmethods)
    return (templateutil.runarithmetic, (func, left, right))


def buildfunc(exp, context):
    n = getsymbol(exp[1])
    if n in context._funcs:
        f = context._funcs[n]
        args = _buildfuncargs(exp[2], context, exprmethods, n, f._argspec)
        return (f, args)
    if n in context._filters:
        args = _buildfuncargs(exp[2], context, exprmethods, n, argspec=None)
        if len(args) != 1:
            raise error.ParseError(_(b"filter %s expects one argument") % n)
        f = context._filters[n]
        return (templateutil.runfilter, (args[0], f))
    raise error.ParseError(_(b"unknown function '%s'") % n)


def _buildfuncargs(exp, context, curmethods, funcname, argspec):
    """Compile parsed tree of function arguments into list or dict of
    (func, data) pairs

    >>> context = engine(lambda t: (templateutil.runsymbol, t))
    >>> def fargs(expr, argspec):
    ...     x = _parseexpr(expr)
    ...     n = getsymbol(x[1])
    ...     return _buildfuncargs(x[2], context, exprmethods, n, argspec)
    >>> list(fargs(b'a(l=1, k=2)', b'k l m').keys())
    ['l', 'k']
    >>> args = fargs(b'a(opts=1, k=2)', b'**opts')
    >>> list(args.keys()), list(args[b'opts'].keys())
    (['opts'], ['opts', 'k'])
    """

    def compiledict(xs):
        return util.sortdict(
            (k, compileexp(x, context, curmethods))
            for k, x in pycompat.iteritems(xs)
        )

    def compilelist(xs):
        return [compileexp(x, context, curmethods) for x in xs]

    if not argspec:
        # filter or function with no argspec: return list of positional args
        return compilelist(getlist(exp))

    # function with argspec: return dict of named args
    _poskeys, varkey, _keys, optkey = argspec = parser.splitargspec(argspec)
    treeargs = parser.buildargsdict(
        getlist(exp),
        funcname,
        argspec,
        keyvaluenode=b'keyvalue',
        keynode=b'symbol',
    )
    compargs = util.sortdict()
    if varkey:
        compargs[varkey] = compilelist(treeargs.pop(varkey))
    if optkey:
        compargs[optkey] = compiledict(treeargs.pop(optkey))
    compargs.update(compiledict(treeargs))
    return compargs


def buildkeyvaluepair(exp, content):
    raise error.ParseError(_(b"can't use a key-value pair in this context"))


def buildlist(exp, context):
    raise error.ParseError(
        _(b"can't use a list in this context"),
        hint=_(b'check place of comma and parens'),
    )


# methods to interpret function arguments or inner expressions (e.g. {_(x)})
exprmethods = {
    b"integer": lambda e, c: (templateutil.runinteger, e[1]),
    b"string": lambda e, c: (templateutil.runstring, e[1]),
    b"symbol": lambda e, c: (templateutil.runsymbol, e[1]),
    b"template": buildtemplate,
    b"group": lambda e, c: compileexp(e[1], c, exprmethods),
    b".": buildmember,
    b"|": buildfilter,
    b"%": buildmap,
    b"func": buildfunc,
    b"keyvalue": buildkeyvaluepair,
    b"list": buildlist,
    b"+": lambda e, c: buildarithmetic(e, c, lambda a, b: a + b),
    b"-": lambda e, c: buildarithmetic(e, c, lambda a, b: a - b),
    b"negate": buildnegate,
    b"*": lambda e, c: buildarithmetic(e, c, lambda a, b: a * b),
    b"/": lambda e, c: buildarithmetic(e, c, lambda a, b: a // b),
}

# methods to interpret top-level template (e.g. {x}, {x|_}, {x % "y"})
methods = exprmethods.copy()
methods[b"integer"] = exprmethods[b"symbol"]  # '{1}' as variable


class _aliasrules(parser.basealiasrules):
    """Parsing and expansion rule set of template aliases"""

    _section = _(b'template alias')
    _parse = staticmethod(_parseexpr)

    @staticmethod
    def _trygetfunc(tree):
        """Return (name, args) if tree is func(...) or ...|filter; otherwise
        None"""
        if tree[0] == b'func' and tree[1][0] == b'symbol':
            return tree[1][1], getlist(tree[2])
        if tree[0] == b'|' and tree[2][0] == b'symbol':
            return tree[2][1], [tree[1]]


def expandaliases(tree, aliases):
    """Return new tree of aliases are expanded"""
    aliasmap = _aliasrules.buildmap(aliases)
    return _aliasrules.expand(aliasmap, tree)


# template engine


def unquotestring(s):
    '''unwrap quotes if any; otherwise returns unmodified string'''
    if len(s) < 2 or s[0] not in b"'\"" or s[0] != s[-1]:
        return s
    return s[1:-1]


class resourcemapper(object):  # pytype: disable=ignored-metaclass
    """Mapper of internal template resources"""

    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod
    def availablekeys(self, mapping):
        """Return a set of available resource keys based on the given mapping"""

    @abc.abstractmethod
    def knownkeys(self):
        """Return a set of supported resource keys"""

    @abc.abstractmethod
    def lookup(self, mapping, key):
        """Return a resource for the key if available; otherwise None"""

    @abc.abstractmethod
    def populatemap(self, context, origmapping, newmapping):
        """Return a dict of additional mapping items which should be paired
        with the given new mapping"""


class nullresourcemapper(resourcemapper):
    def availablekeys(self, mapping):
        return set()

    def knownkeys(self):
        return set()

    def lookup(self, mapping, key):
        return None

    def populatemap(self, context, origmapping, newmapping):
        return {}


class engine(object):
    """template expansion engine.

    template expansion works like this. a map file contains key=value
    pairs. if value is quoted, it is treated as string. otherwise, it
    is treated as name of template file.

    templater is asked to expand a key in map. it looks up key, and
    looks for strings like this: {foo}. it expands {foo} by looking up
    foo in map, and substituting it. expansion is recursive: it stops
    when there is no more {foo} to replace.

    expansion also allows formatting and filtering.

    format uses key to expand each item in list. syntax is
    {key%format}.

    filter uses function to transform value. syntax is
    {key|filter1|filter2|...}."""

    def __init__(self, loader, filters=None, defaults=None, resources=None):
        self._loader = loader
        if filters is None:
            filters = {}
        self._filters = filters
        self._funcs = templatefuncs.funcs  # make this a parameter if needed
        if defaults is None:
            defaults = {}
        if resources is None:
            resources = nullresourcemapper()
        self._defaults = defaults
        self._resources = resources
        self._cache = {}  # key: (func, data)
        self._tmplcache = {}  # literal template: (func, data)

    def overlaymap(self, origmapping, newmapping):
        """Create combined mapping from the original mapping and partial
        mapping to override the original"""
        # do not copy symbols which overrides the defaults depending on
        # new resources, so the defaults will be re-evaluated (issue5612)
        knownres = self._resources.knownkeys()
        newres = self._resources.availablekeys(newmapping)
        mapping = {
            k: v
            for k, v in pycompat.iteritems(origmapping)
            if (
                k in knownres  # not a symbol per self.symbol()
                or newres.isdisjoint(self._defaultrequires(k))
            )
        }
        mapping.update(newmapping)
        mapping.update(
            self._resources.populatemap(self, origmapping, newmapping)
        )
        return mapping

    def _defaultrequires(self, key):
        """Resource keys required by the specified default symbol function"""
        v = self._defaults.get(key)
        if v is None or not callable(v):
            return ()
        return getattr(v, '_requires', ())

    def symbol(self, mapping, key):
        """Resolve symbol to value or function; None if nothing found"""
        v = None
        if key not in self._resources.knownkeys():
            v = mapping.get(key)
        if v is None:
            v = self._defaults.get(key)
        return v

    def availableresourcekeys(self, mapping):
        """Return a set of available resource keys based on the given mapping"""
        return self._resources.availablekeys(mapping)

    def knownresourcekeys(self):
        """Return a set of supported resource keys"""
        return self._resources.knownkeys()

    def resource(self, mapping, key):
        """Return internal data (e.g. cache) used for keyword/function
        evaluation"""
        v = self._resources.lookup(mapping, key)
        if v is None:
            raise templateutil.ResourceUnavailable(
                _(b'template resource not available: %s') % key
            )
        return v

    def _load(self, t):
        '''load, parse, and cache a template'''
        if t not in self._cache:
            x = self._loader(t)
            # put poison to cut recursion while compiling 't'
            self._cache[t] = (_runrecursivesymbol, t)
            try:
                self._cache[t] = compileexp(x, self, methods)
            except:  # re-raises
                del self._cache[t]
                raise
        return self._cache[t]

    def _parse(self, tmpl):
        """Parse and cache a literal template"""
        if tmpl not in self._tmplcache:
            x = parse(tmpl)
            self._tmplcache[tmpl] = compileexp(x, self, methods)
        return self._tmplcache[tmpl]

    def preload(self, t):
        """Load, parse, and cache the specified template if available"""
        try:
            self._load(t)
            return True
        except templateutil.TemplateNotFound:
            return False

    def process(self, t, mapping):
        """Perform expansion. t is name of map element to expand.
        mapping contains added elements for use during expansion. Is a
        generator."""
        func, data = self._load(t)
        return self._expand(func, data, mapping)

    def expand(self, tmpl, mapping):
        """Perform expansion over a literal template

        No user aliases will be expanded since this is supposed to be called
        with an internal template string.
        """
        func, data = self._parse(tmpl)
        return self._expand(func, data, mapping)

    def _expand(self, func, data, mapping):
        # populate additional items only if they don't exist in the given
        # mapping. this is slightly different from overlaymap() because the
        # initial 'revcache' may contain pre-computed items.
        extramapping = self._resources.populatemap(self, {}, mapping)
        if extramapping:
            extramapping.update(mapping)
            mapping = extramapping
        return templateutil.flatten(self, mapping, func(self, mapping, data))


def stylelist():
    path = templatedir()
    if not path:
        return _(b'no templates found, try `hg debuginstall` for more info')
    dirlist = os.listdir(path)
    stylelist = []
    for file in dirlist:
        split = file.split(b".")
        if split[-1] in (b'orig', b'rej'):
            continue
        if split[0] == b"map-cmdline":
            stylelist.append(split[1])
    return b", ".join(sorted(stylelist))


def _open_mapfile(mapfile):
    if os.path.exists(mapfile):
        return util.posixfile(mapfile, b'rb')
    raise error.Abort(
        _(b"style '%s' not found") % mapfile,
        hint=_(b"available styles: %s") % stylelist(),
    )


def _readmapfile(fp, mapfile):
    """Load template elements from the given map file"""
    base = os.path.dirname(mapfile)
    conf = config.config()

    def include(rel, remap, sections):
        subresource = None
        if base:
            abs = os.path.normpath(os.path.join(base, rel))
            if os.path.isfile(abs):
                subresource = util.posixfile(abs, b'rb')
        if not subresource:
            if pycompat.ossep not in rel:
                abs = rel
                subresource = resourceutil.open_resource(
                    b'mercurial.templates', rel
                )
            else:
                dir = templatedir()
                if dir:
                    abs = os.path.normpath(os.path.join(dir, rel))
                    if os.path.isfile(abs):
                        subresource = util.posixfile(abs, b'rb')
        if subresource:
            data = subresource.read()
            conf.parse(
                abs,
                data,
                sections=sections,
                remap=remap,
                include=include,
            )

    data = fp.read()
    conf.parse(mapfile, data, remap={b'': b'templates'}, include=include)

    cache = {}
    tmap = {}
    aliases = []

    val = conf.get(b'templates', b'__base__')
    if val and val[0] not in b"'\"":
        # treat as a pointer to a base class for this style
        path = os.path.normpath(os.path.join(base, val))

        # fallback check in template paths
        if not os.path.exists(path):
            dir = templatedir()
            if dir is not None:
                p2 = os.path.normpath(os.path.join(dir, val))
                if os.path.isfile(p2):
                    path = p2
                else:
                    p3 = os.path.normpath(os.path.join(p2, b"map"))
                    if os.path.isfile(p3):
                        path = p3

        fp = _open_mapfile(path)
        cache, tmap, aliases = _readmapfile(fp, path)

    for key, val in conf[b'templates'].items():
        if not val:
            raise error.ParseError(
                _(b'missing value'), conf.source(b'templates', key)
            )
        if val[0] in b"'\"":
            if val[0] != val[-1]:
                raise error.ParseError(
                    _(b'unmatched quotes'), conf.source(b'templates', key)
                )
            cache[key] = unquotestring(val)
        elif key != b'__base__':
            tmap[key] = os.path.join(base, val)
    aliases.extend(conf[b'templatealias'].items())
    return cache, tmap, aliases


class loader(object):
    """Load template fragments optionally from a map file"""

    def __init__(self, cache, aliases):
        if cache is None:
            cache = {}
        self.cache = cache.copy()
        self._map = {}
        self._aliasmap = _aliasrules.buildmap(aliases)

    def __contains__(self, key):
        return key in self.cache or key in self._map

    def load(self, t):
        """Get parsed tree for the given template name. Use a local cache."""
        if t not in self.cache:
            try:
                mapfile, fp = open_template(self._map[t])
                self.cache[t] = fp.read()
            except KeyError as inst:
                raise templateutil.TemplateNotFound(
                    _(b'"%s" not in template map') % inst.args[0]
                )
            except IOError as inst:
                reason = _(b'template file %s: %s') % (
                    self._map[t],
                    stringutil.forcebytestr(inst.args[1]),
                )
                raise IOError(inst.args[0], encoding.strfromlocal(reason))
        return self._parse(self.cache[t])

    def _parse(self, tmpl):
        x = parse(tmpl)
        if self._aliasmap:
            x = _aliasrules.expand(self._aliasmap, x)
        return x

    def _findsymbolsused(self, tree, syms):
        if not tree:
            return
        op = tree[0]
        if op == b'symbol':
            s = tree[1]
            if s in syms[0]:
                return  # avoid recursion: s -> cache[s] -> s
            syms[0].add(s)
            if s in self.cache or s in self._map:
                # s may be a reference for named template
                self._findsymbolsused(self.load(s), syms)
            return
        if op in {b'integer', b'string'}:
            return
        # '{arg|func}' == '{func(arg)}'
        if op == b'|':
            syms[1].add(getsymbol(tree[2]))
            self._findsymbolsused(tree[1], syms)
            return
        if op == b'func':
            syms[1].add(getsymbol(tree[1]))
            self._findsymbolsused(tree[2], syms)
            return
        for x in tree[1:]:
            self._findsymbolsused(x, syms)

    def symbolsused(self, t):
        """Look up (keywords, filters/functions) referenced from the name
        template 't'

        This may load additional templates from the map file.
        """
        syms = (set(), set())
        self._findsymbolsused(self.load(t), syms)
        return syms


class templater(object):
    def __init__(
        self,
        filters=None,
        defaults=None,
        resources=None,
        cache=None,
        aliases=(),
        minchunk=1024,
        maxchunk=65536,
    ):
        """Create template engine optionally with preloaded template fragments

        - ``filters``: a dict of functions to transform a value into another.
        - ``defaults``: a dict of symbol values/functions; may be overridden
          by a ``mapping`` dict.
        - ``resources``: a resourcemapper object to look up internal data
          (e.g. cache), inaccessible from user template.
        - ``cache``: a dict of preloaded template fragments.
        - ``aliases``: a list of alias (name, replacement) pairs.

        self.cache may be updated later to register additional template
        fragments.
        """
        allfilters = templatefilters.filters.copy()
        if filters:
            allfilters.update(filters)
        self._loader = loader(cache, aliases)
        self._proc = engine(self._loader.load, allfilters, defaults, resources)
        self._minchunk, self._maxchunk = minchunk, maxchunk

    @classmethod
    def frommapfile(
        cls,
        mapfile,
        fp=None,
        filters=None,
        defaults=None,
        resources=None,
        cache=None,
        minchunk=1024,
        maxchunk=65536,
    ):
        """Create templater from the specified map file"""
        t = cls(filters, defaults, resources, cache, [], minchunk, maxchunk)
        if not fp:
            fp = _open_mapfile(mapfile)
        cache, tmap, aliases = _readmapfile(fp, mapfile)
        t._loader.cache.update(cache)
        t._loader._map = tmap
        t._loader._aliasmap = _aliasrules.buildmap(aliases)
        return t

    def __contains__(self, key):
        return key in self._loader

    @property
    def cache(self):
        return self._loader.cache

    # for highlight extension to insert one-time 'colorize' filter
    @property
    def _filters(self):
        return self._proc._filters

    @property
    def defaults(self):
        return self._proc._defaults

    def load(self, t):
        """Get parsed tree for the given template name. Use a local cache."""
        return self._loader.load(t)

    def symbolsuseddefault(self):
        """Look up (keywords, filters/functions) referenced from the default
        unnamed template

        This may load additional templates from the map file.
        """
        return self.symbolsused(b'')

    def symbolsused(self, t):
        """Look up (keywords, filters/functions) referenced from the name
        template 't'

        This may load additional templates from the map file.
        """
        return self._loader.symbolsused(t)

    def renderdefault(self, mapping):
        """Render the default unnamed template and return result as string"""
        return self.render(b'', mapping)

    def render(self, t, mapping):
        """Render the specified named template and return result as string"""
        return b''.join(self.generate(t, mapping))

    def generate(self, t, mapping):
        """Return a generator that renders the specified named template and
        yields chunks"""
        stream = self._proc.process(t, mapping)
        if self._minchunk:
            stream = util.increasingchunks(
                stream, min=self._minchunk, max=self._maxchunk
            )
        return stream


def templatedir():
    '''return the directory used for template files, or None.'''
    path = os.path.normpath(os.path.join(resourceutil.datapath, b'templates'))
    return path if os.path.isdir(path) else None


def open_template(name, templatepath=None):
    """returns a file-like object for the given template, and its full path

    If the name is a relative path and we're in a frozen binary, the template
    will be read from the mercurial.templates package instead. The returned path
    will then be the relative path.
    """
    # Does the name point directly to a map file?
    if os.path.isfile(name) or os.path.isabs(name):
        return name, open(name, mode='rb')

    # Does the name point to a template in the provided templatepath, or
    # in mercurial/templates/ if no path was provided?
    if templatepath is None:
        templatepath = templatedir()
    if templatepath is not None:
        f = os.path.join(templatepath, name)
        return f, open(f, mode='rb')

    # Otherwise try to read it using the resources API
    name_parts = name.split(b'/')
    package_name = b'.'.join([b'mercurial', b'templates'] + name_parts[:-1])
    return (
        name,
        resourceutil.open_resource(package_name, name_parts[-1]),
    )


def try_open_template(name, templatepath=None):
    try:
        return open_template(name, templatepath)
    except (EnvironmentError, ImportError):
        return None, None