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#!/usr/bin/env python 

# -*- coding: UTF-8 -*- 

# 

# Copyright 2014-2019European Commission (JRC); 

# Licensed under the EUPL (the 'Licence'); 

# You may not use this work except in compliance with the Licence. 

# You may obtain a copy of the Licence at: http://ec.europa.eu/idabc/eupl 

""" 

The manager and the base for all :term:`backends` fetching cells from actual workbooks and sheets. 

 

Prefer accessing the public members from the parent module. 

 

.. currentmodule:: pandalone.xleash 

""" 

 

from abc import abstractmethod, ABC 

from collections import namedtuple 

 

import itertools as itt 

import numpy as np 

 

from .. import Coords, _capture, io_backends 

from ... import utils 

 

 

class ABCBackend(ABC): 

"""A plugin for a :term:`backend` must implement and add instances into :data:`io_backends`.""" 

 

@abstractmethod 

def bid(self, wb_url): 

""" 

Express the willingness to handle a workbook when deciding backends. 

 

:param wb_url: 

a full-url of a workbook, local('file://) or remote('http://') 

:return: 

- an integer signifying willingness; bigger integers take precedence. 

- `None` signifies invalidness. 

""" 

 

@abstractmethod 

def open_sheet(self, wb_url, sheet_id): 

""" 

Open a :class:`ABCSheet` subclass, if backend has won the bid. 

 

:param wb_url: 

a full-url of a workbook, local('file://) or remote('http://') 

""" 

 

@abstractmethod 

def list_sheetnames(self, wb_url): 

"""Returns a list of sheet-names, if bids "decided" this backend.""" 

 

 

class SimpleSheetsFactory(object): 

""" 

Asks :term:`backends` to bid for creating :class:`ABCSheet` instances - client should handle resources. 

 

Backends are taken from :data:`io_backends` or specified during construction. 

""" 

 

def __init__(self, backends=None): 

""" 

:param backends: 

The list of :class:`backends` to consider when opening sheets. 

If it evaluates to false, :data:`io_backends` assumed. 

:typ backends: 

list or None 

""" 

self.backends = backends or io_backends 

 

def fetch_sheet(self, wb_url, sheet_id, base_sheet=None): 

""" 

:param ABCSheet base_sheet: 

The sheet used when unspecified `wb_url`. 

""" 

if wb_url is None and base_sheet: 

if sheet_id is None: 

sheet = base_sheet 

else: 

base_sheet.open_sibling_sheet(sheet_id) 

else: 

url = utils.path2url(wb_url) 

sheet = self._open_sheet(url, sheet_id) 

 

assert sheet, (wb_url, sheet_id) 

return sheet 

 

def decide_backend(self, wb_url): 

"""Asks all :attr:`backends` to :term:`bid` for handling a :term:`xl-ref`. """ 

wb_url = utils.path2url(wb_url) 

bids = [(be, be.bid(wb_url)) for be in self.backends] 

bids = [(be, score) for be, score in bids if score is not None] 

if not bids: 

raise ValueError( 

"No suitable xleash-backend found for(%r)!" 

"\n Have you installed `xlrd` extra with this command?" 

"\n pip install pandalone[xlrd]" % wb_url 

) 

winner = sorted(bids, key=lambda x: x[1])[-1][0] 

assert isinstance(winner, ABCBackend), "Invalid backend(%r) class!" % winner 

 

return winner 

 

def list_sheetnames(self, wb_id): 

url = utils.path2url(wb_id) 

be = self.decide_backend(url) 

return be.list_sheetnames(url) 

 

def _open_sheet(self, url, sheet_id): # =None): 

be = self.decide_backend(url) 

sheet = be.open_sheet(url, sheet_id) 

if not sheet: 

raise ValueError("Backend(%s) found no sheet for(%r)!" % (be, url)) 

return sheet 

 

 

class SheetsFactory(SimpleSheetsFactory): 

""" 

A caching-store of :class:`ABCSheet` instances, serving them based on (workbook, sheet) IDs, optionally creating them from backends. 

 

:ivar dict _cached_sheets: 

A cache of all _Spreadsheets accessed so far, 

keyed by multiple keys generated by :meth:`_derive_sheet_keys`. 

 

- To avoid opening non-trivial workbooks, use the :meth:`add_sheet()` 

to pre-populate this cache with them. 

 

- It is a resource-manager for contained sheets, so it can be used wth 

a `with` statement. 

 

""" 

 

def __init__(self, backends=None): 

""" 

:param backends: 

The list of :class:`backends` to consider when opening sheets. 

If it evaluates to false, :data:`io_backends` assumed. 

:typ backends: 

list or None 

""" 

super(SheetsFactory, self).__init__(backends) 

self._cached_sheets = {} 

 

def _cache_get(self, key): 

wb, sh = key 

if wb in self._cached_sheets: 

shs = self._cached_sheets[wb] 

return shs.get(sh, None) 

 

def _cache_put(self, key, sheet): 

wb, sh = key 

if wb in self._cached_sheets: 

sh_dict = self._cached_sheets[wb] 

else: 

sh_dict = self._cached_sheets[wb] = {} 

sh_dict[sh] = sheet 

 

def _build_sheet_key(self, wb, sh): 

assert wb is not None, (wb, sh) 

return (wb, sh) 

 

def _derive_sheet_keys(self, sheet, wb_ids=None, sh_ids=None): 

""" 

Retuns the product of user-specified and sheet-internal keys. 

 

:param wb_ids: 

a single or a sequence of extra workbook-ids (ie: file, url) 

:param sh_ids: 

a single or sequence of extra sheet-ids (ie: name, index, None) 

""" 

wb_id, sh_ids2 = sheet.get_sheet_ids() 

assert wb_id is not None, (wb_id, sh_ids2) 

wb_ids = [wb_id] + utils.as_list(wb_ids) 

sh_ids = sh_ids2 + utils.as_list(sh_ids) 

 

key_pairs = itt.product(wb_ids, sh_ids) 

keys = list(set(self._build_sheet_key(*p) for p in key_pairs if p[0])) 

assert keys, (keys, sheet, wb_ids, sh_ids) 

 

return keys 

 

def _close_sheet(self, key): 

sheet = self._cache_get(key) 

if sheet: 

sheet._close() 

for sh_dict in self._cached_sheets.values(): 

for sh_id, sh in list(sh_dict.items()): 

if sh is sheet: 

del sh_dict[sh_id] 

 

def close(self): 

"""Closes all contained sheets and empties cache.""" 

for sh_dict in self._cached_sheets.values(): 

for sh in sh_dict.values(): 

sh._close_all() 

self._cached_sheets = {} 

 

def add_sheet(self, sheet, wb_ids=None, sh_ids=None): 

""" 

Updates cache. 

 

:param wb_ids: 

a single or sequence of extra workbook-ids (ie: file, url) 

:param sh_ids: 

a single or sequence of extra sheet-ids (ie: name, index, None) 

""" 

assert sheet, (sheet, wb_ids, sh_ids) 

keys = self._derive_sheet_keys(sheet, wb_ids, sh_ids) 

for k in keys: 

old_sheet = self._cache_get(k) 

if old_sheet and old_sheet is not sheet: 

self._close_sheet(k) 

self._cache_put(k, sheet) 

 

def fetch_sheet(self, wb_id, sheet_id, base_sheet=None): 

""" 

:param ABCSheet base_sheet: 

The sheet used when unspecified `wb_id`. 

""" 

if wb_id is None and base_sheet: 

if sheet_id is None: 

sheet = base_sheet 

else: 

wb_id, _c_sh_ids = base_sheet.get_sheet_ids() 

 

key = self._build_sheet_key(wb_id, sheet_id) 

sheet = self._cache_get(key) 

 

if not sheet: 

sheet = base_sheet.open_sibling_sheet(sheet_id) 

self.add_sheet(sheet, wb_id, sheet_id) 

else: 

url = utils.path2url(wb_id) 

if wb_id is None: 

sheet = self._open_sheet(url, sheet_id) 

else: 

key = self._build_sheet_key(wb_id, sheet_id) 

sheet = self._cache_get(key) 

if not sheet: 

sheet = self._open_sheet(url, sheet_id) 

self.add_sheet(sheet, wb_id, sheet_id) 

 

assert sheet, (wb_id, sheet_id) 

return sheet 

 

def __enter__(self): 

return self 

 

def __exit__(self, typ, value, traceback): 

self.close() 

 

 

def margin_coords_from_states_matrix(states_matrix): 

""" 

Returns top-left/bottom-down margins of full cells from a :term:`state` matrix. 

 

May be used by :meth:`ABCSheet.get_margin_coords()` if a backend 

does not report the sheet-margins internally. 

 

:param np.ndarray states_matrix: 

A 2D-array with `False` wherever cell are blank or empty. 

Use :meth:`ABCSheet.get_states_matrix()` to derrive it. 

:return: the 2 coords of the top-left & bottom-right full cells 

:rtype: (Coords, Coords) 

 

Examples:: 

>>> states_matrix = np.asarray([ 

... [0, 0, 0], 

... [0, 1, 0], 

... [0, 1, 1], 

... [0, 0, 1], 

... ]) 

>>> margins = margin_coords_from_states_matrix(states_matrix) 

>>> margins 

(Coords(row=1, col=1), Coords(row=3, col=2)) 

 

 

Note that the botom-left cell is not the same as `states_matrix` matrix size:: 

 

>>> states_matrix = np.asarray([ 

... [0, 0, 0, 0], 

... [0, 1, 0, 0], 

... [0, 1, 1, 0], 

... [0, 0, 1, 0], 

... [0, 0, 0, 0], 

... ]) 

>>> margin_coords_from_states_matrix(states_matrix) == margins 

True 

 

""" 

if not states_matrix.any(): 

c = Coords(0, 0) 

return c, c 

indices = np.array(np.where(states_matrix), dtype=np.int32).T 

 

# return indices.min(0), indices.max(0) 

return Coords(*indices.min(0)), Coords(*indices.max(0)) 

 

 

SheetId = namedtuple("SheetId", ("book", "ids")) 

 

 

class ABCSheet(ABC): 

""" 

A delegating to backend factory and sheet-wrapper with utility methods. 

 

:param np.ndarray _states_matrix: 

The :term:`states-matrix` cached, so recreate object 

to refresh it. 

:param dict _margin_coords: 

limits used by :func:`_resolve_cell`, cached, so recreate object 

to refresh it. 

 

Resource management is outside of the scope of this class, 

and must happen in the backend workbook/sheet instance. 

 

*xlrd* examples:: 

 

>>> import xlrd # doctest: +SKIP 

>>> with xlrd.open_workbook(self.tmp) as wb: # doctest: +SKIP 

... sheet = xleash.xlrdSheet(wb.sheet_by_name('Sheet1')) 

... ## Do whatever 

 

*win32* examples:: 

 

>>> with dsgdsdsfsd as wb: # doctest: +SKIP 

... sheet = xleash.win32Sheet(wb.sheet['Sheet1']) 

TODO: Win32 Sheet example 

""" 

 

_states_matrix = None 

_margin_coords = None 

 

def _close(self): 

""" Override it to release resources for this sheet.""" 

 

def _close_all(self): 

""" Override it to release resources this and all sibling sheets.""" 

 

@abstractmethod 

def get_sheet_ids(self): 

""" 

:return: a 2-tuple of its wb-name and a sheet-ids of this sheet i.e. name & indx 

:rtype: SheetId or None 

""" 

 

@abstractmethod 

def open_sibling_sheet(self, sheet_id): 

"""Return a sibling sheet by the given index or name""" 

 

@abstractmethod 

def list_sheetnames(self): 

"""Return a list of names""" 

 

@abstractmethod 

def _read_states_matrix(self): 

""" 

Read the :term:`states-matrix` of the wrapped sheet. 

 

:return: A 2D-array with `False` wherever cell are blank or empty. 

:rtype: ndarray 

""" 

 

def get_states_matrix(self): 

""" 

Read and cache the :term:`states-matrix` of the wrapped sheet. 

 

:return: A 2D-array with `False` wherever cell are blank or empty. 

:rtype: ndarray 

:raise: EmptyCaptureException if sheet empty 

""" 

if self._states_matrix is None: 

self._states_matrix = self._read_states_matrix() 

return self._states_matrix 

 

@abstractmethod 

def read_rect(self, st, nd): 

""" 

Fecth the actual values from the backend Excel-sheet. 

 

:param Coords st: 

the top-left edge, inclusive 

:param Coords, None nd: 

the bottom-right edge, inclusive(!); when `None`, 

must return a scalar value. 

:type nd: Coords, None 

:return: 

Depends on whether both coords are given: 

- If both given, 2D list-lists with the values of the rect, 

which might be empty if beyond limits. 

- If only 1st given, the scalar value, and if 

beyond margins, raise error! 

 

:rtype: list 

:raise: EmptyCaptureException (optionally) if sheet empty 

""" 

 

def _read_margin_coords(self): 

""" 

Override if possible to read (any of the) limits directly from the sheet. 

 

:return: the 2 coords of the top-left & bottom-right full cells; 

anyone coords can be None. 

By default returns ``(None, None)``. 

:rtype: (Coords, Coords) 

:raise: EmptyCaptureException if sheet empty 

""" 

return None, None # pragma: no cover 

 

def get_margin_coords(self): 

""" 

Extract (and cache) margins either internally or from :func:`margin_coords_from_states_matrix()`. 

 

:return: the resolved top-left and bottom-right :class:`.xleash.Coords` 

:rtype: tuple 

:raise: EmptyCaptureException if sheet empty 

""" 

if not self._margin_coords: 

up, dn = self._read_margin_coords() 

if up is None or dn is None: 

sm = self.get_states_matrix() 

up1, dn1 = margin_coords_from_states_matrix(sm) 

up = up or up1 

dn = dn or dn1 

self._margin_coords = up, dn 

 

return self._margin_coords 

 

def __repr__(self): 

args = (type(self).__name__,) + self.get_sheet_ids() 

return "%s(book=%r, sheet_ids=%r)" % args 

 

 

class ArraySheet(ABCSheet): 

"""A sample :class:`ABCSheet` made out of 2D-list or numpy-arrays, for facilitating tests.""" 

 

def __init__(self, arr, ids=SheetId("wb", ["sh", 0])): 

self._arr = np.asarray(arr) 

self._ids = ids 

 

def open_sibling_sheet(self, sheet_id): 

raise NotImplementedError() 

 

def get_sheet_ids(self): 

return self._ids 

 

def list_sheetnames(self): 

return [self._ids.ids[0]] 

 

def _read_states_matrix(self): 

if not self._arr.size: 

raise _capture.EmptyCaptureException("empty sheet") 

return ~np.equal(self._arr, None) 

 

def read_rect(self, st, nd): 

if not self._arr.size: 

raise _capture.EmptyCaptureException("empty sheet") 

if nd is None: 

return self._arr[st] 

rect = np.array([st, nd]) + [[0, 0], [1, 1]] 

return self._arr[slice(*rect[:, 0]), slice(*rect[:, 1])].tolist() 

 

def __repr__(self): 

return "ArraySheet(%s, \n%s)" % (self.get_sheet_ids(), self._arr)