<reponame>jochenater/catboost
"""Cache lines from Python source files.

This is intended to read lines from modules imported -- hence if a filename
is not found, it will look down the module search path for a file by
that name.
"""

import functools
import sys
import os
import tokenize

__all__ = ["getline", "clearcache", "checkcache", "lazycache"]


# The cache. Maps filenames to either a thunk which will provide source code,
# or a tuple (size, mtime, lines, fullname) once loaded.
cache = {}


def clearcache():
    """Clear the cache entirely."""
    cache.clear()


def getline(filename, lineno, module_globals=None):
    """Get a line for a Python source file from the cache.
    Update the cache if it doesn't contain an entry for this file already."""

    lines = getlines(filename, module_globals)
    if 1 <= lineno <= len(lines):
        return lines[lineno - 1]
    return ''


def getlines(filename, module_globals=None):
    """Get the lines for a Python source file from the cache.
    Update the cache if it doesn't contain an entry for this file already."""

    if filename in cache:
        entry = cache[filename]
        if len(entry) != 1:
            return cache[filename][2]

    try:
        return updatecache(filename, module_globals)
    except MemoryError:
        clearcache()
        return []


def checkcache(filename=None):
    """Discard cache entries that are out of date.
    (This is not checked upon each call!)"""

    if filename is None:
        filenames = list(cache.keys())
    elif filename in cache:
        filenames = [filename]
    else:
        return

    for filename in filenames:
        entry = cache[filename]
        if len(entry) == 1:
            # lazy cache entry, leave it lazy.
            continue
        size, mtime, lines, fullname = entry
        if mtime is None:
            continue   # no-op for files loaded via a __loader__
        try:
            stat = os.stat(fullname)
        except OSError:
            cache.pop(filename, None)
            continue
        if size != stat.st_size or mtime != stat.st_mtime:
            cache.pop(filename, None)


def updatecache(filename, module_globals=None):
    """Update a cache entry and return its list of lines.
    If something's wrong, print a message, discard the cache entry,
    and return an empty list."""

    if filename in cache:
        if len(cache[filename]) != 1:
            cache.pop(filename, None)
    if not filename or (filename.startswith('<') and filename.endswith('>')):
        return []

    if not os.path.isabs(filename):
        # Do not read builtin code from the filesystem.
        import __res
        key = __res.importer.file_source(filename)
        if key:
            data = __res.find(key)
            assert data is not None, filename
            data = data.decode('UTF-8')
            lines = [line + '\n' for line in data.splitlines()]
            cache[filename] = (len(data), None, lines, filename)
            return cache[filename][2]

    fullname = filename
    try:
        stat = os.stat(fullname)
    except OSError:
        basename = filename

        # Realise a lazy loader based lookup if there is one
        # otherwise try to lookup right now.
        if lazycache(filename, module_globals):
            try:
                data = cache[filename][0]()
            except (ImportError, OSError):
                pass
            else:
                if data is None:
                    # No luck, the PEP302 loader cannot find the source
                    # for this module.
                    return []
                cache[filename] = (
                    len(data),
                    None,
                    [line + '\n' for line in data.splitlines()],
                    fullname
                )
                return cache[filename][2]

        # Try looking through the module search path, which is only useful
        # when handling a relative filename.
        if os.path.isabs(filename):
            return []

        for dirname in sys.path:
            try:
                fullname = os.path.join(dirname, basename)
            except (TypeError, AttributeError):
                # Not sufficiently string-like to do anything useful with.
                continue
            try:
                stat = os.stat(fullname)
                break
            except OSError:
                pass
        else:
            return []
    try:
        with tokenize.open(fullname) as fp:
            lines = fp.readlines()
    except OSError:
        return []
    if lines and not lines[-1].endswith('\n'):
        lines[-1] += '\n'
    size, mtime = stat.st_size, stat.st_mtime
    cache[filename] = size, mtime, lines, fullname
    return lines


def lazycache(filename, module_globals):
    """Seed the cache for filename with module_globals.

    The module loader will be asked for the source only when getlines is
    called, not immediately.

    If there is an entry in the cache already, it is not altered.

    :return: True if a lazy load is registered in the cache,
        otherwise False. To register such a load a module loader with a
        get_source method must be found, the filename must be a cacheable
        filename, and the filename must not be already cached.
    """
    if filename in cache:
        if len(cache[filename]) == 1:
            return True
        else:
            return False
    if not filename or (filename.startswith('<') and filename.endswith('>')):
        return False
    # Try for a __loader__, if available
    if module_globals and '__loader__' in module_globals:
        name = module_globals.get('__name__')
        loader = module_globals['__loader__']
        get_source = getattr(loader, 'get_source', None)

        if name and get_source:
            get_lines = functools.partial(get_source, name)
            cache[filename] = (get_lines,)
            return True
    return False

"""Cache lines from Python source files.

This is intended to read lines from modules imported -- hence if a filename
is not found, it will look down the module search path for a file by
that name.
"""

import functools
import sys
import os
import tokenize

__all__ = ["getline", "clearcache", "checkcache", "lazycache"]


# The cache. Maps filenames to either a thunk which will provide source code,
# or a tuple (size, mtime, lines, fullname) once loaded.
cache = {}


def clearcache():
    """Clear the cache entirely."""
    cache.clear()


def getline(filename, lineno, module_globals=None):
    """Get a line for a Python source file from the cache.
    Update the cache if it doesn't contain an entry for this file already."""

    lines = getlines(filename, module_globals)
    if 1 <= lineno <= len(lines):
        return lines[lineno - 1]
    return ''


def getlines(filename, module_globals=None):
    """Get the lines for a Python source file from the cache.
    Update the cache if it doesn't contain an entry for this file already."""

    if filename in cache:
        entry = cache[filename]
        if len(entry) != 1:
            return cache[filename][2]

    try:
        return updatecache(filename, module_globals)
    except MemoryError:
        clearcache()
        return []


def checkcache(filename=None):
    """Discard cache entries that are out of date.
    (This is not checked upon each call!)"""

    if filename is None:
        filenames = list(cache.keys())
    elif filename in cache:
        filenames = [filename]
    else:
        return

    for filename in filenames:
        entry = cache[filename]
        if len(entry) == 1:
            # lazy cache entry, leave it lazy.
            continue
        size, mtime, lines, fullname = entry
        if mtime is None:
            continue   # no-op for files loaded via a __loader__
        try:
            stat = os.stat(fullname)
        except OSError:
            cache.pop(filename, None)
            continue
        if size != stat.st_size or mtime != stat.st_mtime:
            cache.pop(filename, None)


def updatecache(filename, module_globals=None):
    """Update a cache entry and return its list of lines.
    If something's wrong, print a message, discard the cache entry,
    and return an empty list."""

    if filename in cache:
        if len(cache[filename]) != 1:
            cache.pop(filename, None)
    if not filename or (filename.startswith('<') and filename.endswith('>')):
        return []

    if not os.path.isabs(filename):
        # Do not read builtin code from the filesystem.
        import __res
        key = __res.importer.file_source(filename)
        if key:
            data = __res.find(key)
            assert data is not None, filename
            data = data.decode('UTF-8')
            lines = [line + '\n' for line in data.splitlines()]
            cache[filename] = (len(data), None, lines, filename)
            return cache[filename][2]

    fullname = filename
    try:
        stat = os.stat(fullname)
    except OSError:
        basename = filename

        # Realise a lazy loader based lookup if there is one
        # otherwise try to lookup right now.
        if lazycache(filename, module_globals):
            try:
                data = cache[filename][0]()
            except (ImportError, OSError):
                pass
            else:
                if data is None:
                    # No luck, the PEP302 loader cannot find the source
                    # for this module.
                    return []
                cache[filename] = (
                    len(data),
                    None,
                    [line + '\n' for line in data.splitlines()],
                    fullname
                )
                return cache[filename][2]

        # Try looking through the module search path, which is only useful
        # when handling a relative filename.
        if os.path.isabs(filename):
            return []

        for dirname in sys.path:
            try:
                fullname = os.path.join(dirname, basename)
            except (TypeError, AttributeError):
                # Not sufficiently string-like to do anything useful with.
                continue
            try:
                stat = os.stat(fullname)
                break
            except OSError:
                pass
        else:
            return []
    try:
        with tokenize.open(fullname) as fp:
            lines = fp.readlines()
    except OSError:
        return []
    if lines and not lines[-1].endswith('\n'):
        lines[-1] += '\n'
    size, mtime = stat.st_size, stat.st_mtime
    cache[filename] = size, mtime, lines, fullname
    return lines


def lazycache(filename, module_globals):
    """Seed the cache for filename with module_globals.

    The module loader will be asked for the source only when getlines is
    called, not immediately.

    If there is an entry in the cache already, it is not altered.

    :return: True if a lazy load is registered in the cache,
        otherwise False. To register such a load a module loader with a
        get_source method must be found, the filename must be a cacheable
        filename, and the filename must not be already cached.
    """
    if filename in cache:
        if len(cache[filename]) == 1:
            return True
        else:
            return False
    if not filename or (filename.startswith('<') and filename.endswith('>')):
        return False
    # Try for a __loader__, if available
    if module_globals and '__loader__' in module_globals:
        name = module_globals.get('__name__')
        loader = module_globals['__loader__']
        get_source = getattr(loader, 'get_source', None)

        if name and get_source:
            get_lines = functools.partial(get_source, name)
            cache[filename] = (get_lines,)
            return True
    return False
Cache lines from Python source files.  This is intended to read lines from modules imported -- hence if a filename is not found, it will look down the module search path for a file by that name. # The cache. Maps filenames to either a thunk which will provide source code, # or a tuple (size, mtime, lines, fullname) once loaded. Clear the cache entirely. Get a line for a Python source file from the cache.     Update the cache if it doesn't contain an entry for this file already. Get the lines for a Python source file from the cache.     Update the cache if it doesn't contain an entry for this file already. Discard cache entries that are out of date.     (This is not checked upon each call!) # lazy cache entry, leave it lazy. # no-op for files loaded via a __loader__ Update a cache entry and return its list of lines.     If something's wrong, print a message, discard the cache entry,     and return an empty list. # Do not read builtin code from the filesystem. # Realise a lazy loader based lookup if there is one # otherwise try to lookup right now. # No luck, the PEP302 loader cannot find the source # for this module. # Try looking through the module search path, which is only useful # when handling a relative filename. # Not sufficiently string-like to do anything useful with. Seed the cache for filename with module_globals.      The module loader will be asked for the source only when getlines is     called, not immediately.      If there is an entry in the cache already, it is not altered.      :return: True if a lazy load is registered in the cache,         otherwise False. To register such a load a module loader with a         get_source method must be found, the filename must be a cacheable         filename, and the filename must not be already cached. # Try for a __loader__, if available