# functions for handling ABI checking of libraries

import os
import sys
import re
import fnmatch

from waflib import Options, Utils, Logs, Task, Build, Errors
from waflib.TaskGen import feature, before, after
from wafsamba import samba_utils

# these type maps cope with platform specific names for common types
# please add new type mappings into the list below
abi_type_maps = {
    '_Bool' : 'bool',
    'struct __va_list_tag *' : 'va_list'
    }

version_key = lambda x: list(map(int, x.split(".")))

def normalise_signature(sig):
    '''normalise a signature from gdb'''
    sig = sig.strip()
    sig = re.sub(r'^\$[0-9]+\s=\s\{(.+)\}$', r'\1', sig)
    sig = re.sub(r'^\$[0-9]+\s=\s\{(.+)\}(\s0x[0-9a-f]+\s<\w+>)+$', r'\1', sig)
    sig = re.sub(r'^\$[0-9]+\s=\s(0x[0-9a-f]+)\s?(<\w+>)?$', r'\1', sig)
    sig = re.sub(r'0x[0-9a-f]+', '0xXXXX', sig)
    sig = re.sub('", <incomplete sequence (\\\\[a-z0-9]+)>', r'\1"', sig)

    for t in abi_type_maps:
        # we need to cope with non-word characters in mapped types
        m = t
        m = m.replace('*', r'\*')
        if m[-1].isalnum() or m[-1] == '_':
            m += '\\b'
        if m[0].isalnum() or m[0] == '_':
            m = '\\b' + m
        sig = re.sub(m, abi_type_maps[t], sig)
    return sig


def normalise_varargs(sig):
    '''cope with older versions of gdb'''
    sig = re.sub(r',\s\.\.\.', '', sig)
    # Make sure we compare bytes and not strings
    return bytes(sig, encoding='utf-8').decode('unicode_escape')


def parse_sigs(sigs, abi_match):
    '''parse ABI signatures file'''
    abi_match = samba_utils.TO_LIST(abi_match)
    ret = {}
    a = sigs.split('\n')
    for s in a:
        if s.find(':') == -1:
            continue
        sa = s.split(':')
        if abi_match:
            matched = False
            negative = False
            for p in abi_match:
                if p[0] == '!' and fnmatch.fnmatch(sa[0], p[1:]):
                    negative = True
                    break
                elif fnmatch.fnmatch(sa[0], p):
                    matched = True
                    break
            if (not matched) and negative:
                continue
        Logs.debug("%s -> %s" % (sa[1], normalise_signature(sa[1])))
        ret[sa[0]] = normalise_signature(sa[1])
    return ret

def save_sigs(sig_file, parsed_sigs):
    '''save ABI signatures to a file'''
    sigs = "".join('%s: %s\n' % (s, parsed_sigs[s]) for s in sorted(parsed_sigs.keys()))
    return samba_utils.save_file(sig_file, sigs, create_dir=True)


def abi_check_task(self):
    '''check if the ABI has changed'''
    abi_gen = self.ABI_GEN

    libpath = self.inputs[0].abspath(self.env)
    libname = os.path.basename(libpath)

    sigs = samba_utils.get_string(Utils.cmd_output([abi_gen, libpath]))
    parsed_sigs = parse_sigs(sigs, self.ABI_MATCH)

    sig_file = self.ABI_FILE

    old_sigs = samba_utils.load_file(sig_file)
    if old_sigs is None or Options.options.ABI_UPDATE:
        if not save_sigs(sig_file, parsed_sigs):
            raise Errors.WafError('Failed to save ABI file "%s"' % sig_file)
        Logs.warn('Generated ABI signatures %s' % sig_file)
        return

    parsed_old_sigs = parse_sigs(old_sigs, self.ABI_MATCH)

    # check all old sigs
    got_error = False
    for s in parsed_old_sigs:
        if not s in parsed_sigs:
            Logs.error('%s: symbol %s has been removed - please update major version\n\tsignature: %s' % (
                libname, s, parsed_old_sigs[s]))
            got_error = True
        elif normalise_varargs(parsed_old_sigs[s]) != normalise_varargs(parsed_sigs[s]):
            Logs.error('%s: symbol %s has changed - please update major version\n\told_signature: %s\n\tnew_signature: %s' % (
                libname, s, parsed_old_sigs[s], parsed_sigs[s]))
            got_error = True

    for s in parsed_sigs:
        if not s in parsed_old_sigs:
            Logs.error('%s: symbol %s has been added - please mark it _PRIVATE_ or update minor version\n\tsignature: %s' % (
                libname, s, parsed_sigs[s]))
            got_error = True

    if got_error:
        raise Errors.WafError('ABI for %s has changed - please fix library version then build with --abi-update\nSee http://wiki.samba.org/index.php/Waf#ABI_Checking for more information\nIf you have not changed any ABI, and your platform always gives this error, please configure with --abi-check-disable to skip this check' % libname)


t = Task.task_factory('abi_check', abi_check_task, color='BLUE', ext_in='.bin')
t.quiet = True
# allow "waf --abi-check" to force re-checking the ABI
if '--abi-check' in sys.argv:
    t.always_run = True

@after('apply_link')
@feature('abi_check')
def abi_check(self):
    '''check that ABI matches saved signatures'''
    env = self.bld.env
    if not env.ABI_CHECK or self.abi_directory is None:
        return

    # if the platform doesn't support -fvisibility=hidden then the ABI
    # checks become fairly meaningless
    if not env.HAVE_VISIBILITY_ATTR:
        return

    topsrc = self.bld.srcnode.abspath()
    abi_gen = os.path.join(topsrc, 'buildtools/scripts/abi_gen.sh')

    abi_file = "%s/%s-%s.sigs" % (self.abi_directory, self.version_libname,
                                  self.abi_vnum)

    tsk = self.create_task('abi_check', self.link_task.outputs[0])
    tsk.ABI_FILE = abi_file
    tsk.ABI_MATCH = self.abi_match
    tsk.ABI_GEN = abi_gen


def abi_process_file(fname, version, symmap):
    '''process one ABI file, adding new symbols to the symmap'''
    for line in Utils.readf(fname).splitlines():
        symname = line.split(":")[0]
        if not symname in symmap:
            symmap[symname] = version

def version_script_map_process_file(fname, version, abi_match):
    '''process one standard version_script file, adding the symbols to the
    abi_match'''
    in_section = False
    in_global = False
    in_local = False
    for _line in Utils.readf(fname).splitlines():
        line = _line.strip()
        if line == "":
            continue
        if line.startswith("#"):
            continue
        if line.endswith(" {"):
            in_section = True
            continue
        if line == "};":
            assert in_section
            in_section = False
            in_global = False
            in_local = False
            continue
        if not in_section:
            continue
        if line == "global:":
            in_global = True
            in_local = False
            continue
        if line == "local:":
            in_global = False
            in_local = True
            continue

        symname = line.split(";")[0]
        assert symname != ""
        if in_local:
            if symname == "*":
                continue
            symname = "!%s" % symname
        if not symname in abi_match:
            abi_match.append(symname)

def abi_write_vscript(f, libname, current_version, versions, symmap, abi_match):
    """Write a vscript file for a library in --version-script format.

    :param f: File-like object to write to
    :param libname: Name of the library, uppercased
    :param current_version: Current version
    :param versions: Versions to consider
    :param symmap: Dictionary mapping symbols -> version
    :param abi_match: List of symbols considered to be public in the current
        version
    """

    invmap = {}
    for s in symmap:
        invmap.setdefault(symmap[s], []).append(s)

    last_key = ""
    versions = sorted(versions, key=version_key)
    for k in versions:
        symver = "%s_%s" % (libname, k)
        if symver == current_version:
            break
        f.write("%s {\n" % symver)
        if k in sorted(invmap.keys()):
            f.write("\tglobal:\n")
            for s in invmap.get(k, []):
                f.write("\t\t%s;\n" % s)
        f.write("}%s;\n\n" % last_key)
        last_key = " %s" % symver
    f.write("%s {\n" % current_version)
    local_abi = list(filter(lambda x: x[0] == '!', abi_match))
    global_abi = list(filter(lambda x: x[0] != '!', abi_match))
    f.write("\tglobal:\n")
    if len(global_abi) > 0:
        for x in global_abi:
            f.write("\t\t%s;\n" % x)
    else:
        f.write("\t\t*;\n")
    # Always hide symbols that must be local if exist
    local_abi.extend(["!_end", "!__bss_start", "!_edata"])
    f.write("\tlocal:\n")
    for x in local_abi:
        f.write("\t\t%s;\n" % x[1:])
    if global_abi != ["*"]:
        if len(global_abi) > 0:
            f.write("\t\t*;\n")
    f.write("};\n")


def abi_build_vscript(task):
    '''generate a vscript file for our public libraries'''

    tgt = task.outputs[0].bldpath(task.env)

    symmap = {}
    versions = []
    abi_match = list(task.env.ABI_MATCH)
    for f in task.inputs:
        fname = f.abspath(task.env)
        basename = os.path.basename(fname)
        if basename.endswith(".sigs"):
            version = basename[len(task.env.LIBNAME)+1:-len(".sigs")]
            versions.append(version)
            abi_process_file(fname, version, symmap)
            continue
        if basename == "version-script.map":
            version_script_map_process_file(fname, task.env.VERSION, abi_match)
            continue
        raise Errors.WafError('Unsupported input "%s"' % fname)
    if task.env.PRIVATE_LIBRARY:
        # For private libraries we need to inject
        # each public symbol explicitly into the
        # abi match array and remove all explicit
        # versioning so that each exported symbol
        # is tagged with the private library tag.
        for s in symmap:
            abi_match.append(s)
        symmap = {}
        versions = []
    f = open(tgt, mode='w')
    try:
        abi_write_vscript(f, task.env.LIBNAME, task.env.VERSION, versions,
            symmap, abi_match)
    finally:
        f.close()

def VSCRIPT_MAP_PRIVATE(bld, libname, orig_vscript, version, private_vscript):
    version = version.replace("-", "_").replace("+","_").upper()
    t = bld.SAMBA_GENERATOR(private_vscript,
                            rule=abi_build_vscript,
                            source=orig_vscript,
                            group='vscripts',
                            target=private_vscript)
    t.env.ABI_MATCH = []
    t.env.VERSION = version
    t.env.LIBNAME = libname
    t.env.PRIVATE_LIBRARY = True
    t.vars = ['LIBNAME', 'VERSION', 'ABI_MATCH', 'PRIVATE_LIBRARY']
Build.BuildContext.VSCRIPT_MAP_PRIVATE = VSCRIPT_MAP_PRIVATE

def ABI_VSCRIPT(bld, libname, abi_directory, version, vscript, abi_match=None, private_library=False):
    '''generate a vscript file for our public libraries'''
    if abi_directory:
        source = bld.path.ant_glob('%s/%s-[0-9]*.sigs' % (abi_directory, libname), flat=True)
        def abi_file_key(path):
            return version_key(path[:-len(".sigs")].rsplit("-")[-1])
        source = sorted(source.split(), key=abi_file_key)
    else:
        source = ''

    if private_library is None:
        private_library = False

    libname = os.path.basename(libname)
    version = os.path.basename(version)
    libname = libname.replace("-", "_").replace("+","_").upper()
    version = version.replace("-", "_").replace("+","_").upper()

    t = bld.SAMBA_GENERATOR(vscript,
                            rule=abi_build_vscript,
                            source=source,
                            group='vscripts',
                            target=vscript)
    if abi_match is None:
        abi_match = ["*"]
    else:
        abi_match = samba_utils.TO_LIST(abi_match)
    t.env.ABI_MATCH = abi_match
    t.env.VERSION = version
    t.env.LIBNAME = libname
    t.env.PRIVATE_LIBRARY = private_library
    t.vars = ['LIBNAME', 'VERSION', 'ABI_MATCH', 'PRIVATE_LIBRARY']
Build.BuildContext.ABI_VSCRIPT = ABI_VSCRIPT