Source code for calibre.ebooks.oeb.polish.split

#!/usr/bin/env python


__license__ = 'GPL v3'
__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'

import copy
import os
import re

from calibre.ebooks.oeb.base import OEB_DOCS, OPF, XHTML, XPNSMAP, XPath, barename
from calibre.ebooks.oeb.polish.errors import MalformedMarkup
from calibre.ebooks.oeb.polish.replace import LinkRebaser
from calibre.ebooks.oeb.polish.toc import node_from_loc
from polyglot.builtins import iteritems, string_or_bytes
from polyglot.urllib import urlparse


class AbortError(ValueError):
    pass


def in_table(node):
    while node is not None:
        if node.tag.endswith('}table'):
            return True
        node = node.getparent()
    return False


def adjust_split_point(split_point, log):
    '''
    Move the split point up its ancestor chain if it has no content
    before it. This handles the common case:
    <div id="chapter1"><h2>Chapter 1</h2>...</div> with a page break on the
    h2.
    '''
    sp = split_point
    while True:
        parent = sp.getparent()
        if (
            parent is None or
            barename(parent.tag) in {'body', 'html'} or
            (parent.text and parent.text.strip()) or
            parent.index(sp) > 0
        ):
            break
        sp = parent

    if sp is not split_point:
        log.debug('Adjusted split point to ancestor')

    return sp


def get_body(root):
    return root.find('h:body', namespaces=XPNSMAP)


def do_split(split_point, log, before=True):
    '''
    Split tree into a *before* and an *after* tree at ``split_point``.

    :param split_point: The Element at which to split
    :param before: If True tree is split before split_point, otherwise after split_point
    :return: before_tree, after_tree
    '''
    if before:
        # We cannot adjust for after since moving an after split point to a
        # parent will cause breakage if the parent contains any content
        # after the original split point
        split_point = adjust_split_point(split_point, log)
    tree         = split_point.getroottree()
    path         = tree.getpath(split_point)

    tree, tree2  = copy.deepcopy(tree), copy.deepcopy(tree)
    root, root2  = tree.getroot(), tree2.getroot()
    body, body2  = map(get_body, (root, root2))
    split_point  = root.xpath(path)[0]
    split_point2 = root2.xpath(path)[0]

    def nix_element(elem, top=True):
        # Remove elem unless top is False in which case replace elem by its
        # children
        parent = elem.getparent()
        if top:
            parent.remove(elem)
        else:
            index = parent.index(elem)
            parent[index:index+1] = list(elem.iterchildren())

    # Tree 1
    hit_split_point = False
    keep_descendants = False
    split_point_descendants = frozenset(split_point.iterdescendants())
    for elem in tuple(body.iterdescendants()):
        if elem is split_point:
            hit_split_point = True
            if before:
                nix_element(elem)
            else:
                # We want to keep the descendants of the split point in
                # Tree 1
                keep_descendants = True
                # We want the split point element, but not its tail
                elem.tail = '\n'

            continue
        if hit_split_point:
            if keep_descendants:
                if elem in split_point_descendants:
                    # elem is a descendant keep it
                    continue
                else:
                    # We are out of split_point, so prevent further set
                    # lookups of split_point_descendants
                    keep_descendants = False
            nix_element(elem)

    # Tree 2
    ancestors = frozenset(XPath('ancestor::*')(split_point2))
    for elem in tuple(body2.iterdescendants()):
        if elem is split_point2:
            if not before:
                # Keep the split point element's tail, if it contains non-whitespace
                # text
                tail = elem.tail
                if tail and not tail.isspace():
                    parent = elem.getparent()
                    idx = parent.index(elem)
                    if idx == 0:
                        parent.text = (parent.text or '') + tail
                    else:
                        sib = parent[idx-1]
                        sib.tail = (sib.tail or '') + tail
                # Remove the element itself
                nix_element(elem)
            break
        if elem in ancestors:
            # We have to preserve the ancestors as they could have CSS
            # styles that are inherited/applicable, like font or
            # width. So we only remove the text, if any.
            elem.text = '\n'
        else:
            nix_element(elem, top=False)

    body2.text = '\n'

    return tree, tree2


class SplitLinkReplacer:

    def __init__(self, base, bottom_anchors, top_name, bottom_name, container):
        self.bottom_anchors, self.bottom_name = bottom_anchors, bottom_name
        self.container, self.top_name = container, top_name
        self.base = base
        self.replaced = False

    def __call__(self, url):
        if url and url.startswith('#'):
            return url
        name = self.container.href_to_name(url, self.base)
        if name != self.top_name:
            return url
        purl = urlparse(url)
        if purl.fragment and purl.fragment in self.bottom_anchors:
            url = self.container.name_to_href(self.bottom_name, self.base) + '#' + purl.fragment
            self.replaced = True
        return url


[docs] def split(container, name, loc_or_xpath, before=True, totals=None): ''' Split the file specified by name at the position specified by loc_or_xpath. Splitting automatically migrates all links and references to the affected files. :param loc_or_xpath: Should be an XPath expression such as //h:div[@id="split_here"]. Can also be a *loc* which is used internally to implement splitting in the preview panel. :param before: If True the split occurs before the identified element otherwise after it. :param totals: Used internally ''' root = container.parsed(name) if isinstance(loc_or_xpath, str): split_point = root.xpath(loc_or_xpath)[0] else: try: split_point = node_from_loc(root, loc_or_xpath, totals=totals) except MalformedMarkup: # The webkit HTML parser and the container parser have yielded # different node counts, this can happen if the file is valid XML # but contains constructs like nested <p> tags. So force parse it # with the HTML 5 parser and try again. raw = container.raw_data(name) root = container.parse_xhtml(raw, fname=name, force_html5_parse=True) try: split_point = node_from_loc(root, loc_or_xpath, totals=totals) except MalformedMarkup: raise MalformedMarkup(_('The file %s has malformed markup. Try running the Fix HTML tool' ' before splitting') % name) container.replace(name, root) if in_table(split_point): raise AbortError('Cannot split inside tables') if split_point.tag.endswith('}body'): raise AbortError('Cannot split on the <body> tag') tree1, tree2 = do_split(split_point, container.log, before=before) root1, root2 = tree1.getroot(), tree2.getroot() anchors_in_top = frozenset(root1.xpath('//*/@id')) | frozenset(root1.xpath('//*/@name')) | {''} anchors_in_bottom = frozenset(root2.xpath('//*/@id')) | frozenset(root2.xpath('//*/@name')) base, ext = name.rpartition('.')[0::2] base = re.sub(r'_split\d+$', '', base) nname, s = None, 0 while not nname or container.exists(nname): s += 1 nname = '%s_split%d.%s' % (base, s, ext) manifest_item = container.generate_item(nname, media_type=container.mime_map[name]) bottom_name = container.href_to_name(manifest_item.get('href'), container.opf_name) # Fix links in the split trees for r in (root1, root2): for a in r.xpath('//*[@href]'): url = a.get('href') if url.startswith('#'): fname = name else: fname = container.href_to_name(url, name) if fname == name: purl = urlparse(url) if purl.fragment in anchors_in_top: if r is root2: a.set('href', f'{container.name_to_href(name, bottom_name)}#{purl.fragment}') else: a.set('href', '#' + purl.fragment) elif purl.fragment in anchors_in_bottom: if r is root1: a.set('href', f'{container.name_to_href(bottom_name, name)}#{purl.fragment}') else: a.set('href', '#' + purl.fragment) # Fix all links in the container that point to anchors in the bottom tree for fname, media_type in iteritems(container.mime_map): if fname not in {name, bottom_name}: repl = SplitLinkReplacer(fname, anchors_in_bottom, name, bottom_name, container) container.replace_links(fname, repl) container.replace(name, root1) container.replace(bottom_name, root2) spine = container.opf_xpath('//opf:spine')[0] for spine_item, spine_name, linear in container.spine_iter: if spine_name == name: break index = spine.index(spine_item) + 1 si = spine.makeelement(OPF('itemref'), idref=manifest_item.get('id')) if not linear: si.set('linear', 'no') container.insert_into_xml(spine, si, index=index) container.dirty(container.opf_name) return bottom_name
[docs] def multisplit(container, name, xpath, before=True): ''' Split the specified file at multiple locations (all tags that match the specified XPath expression). See also: :func:`split`. Splitting automatically migrates all links and references to the affected files. :param before: If True the splits occur before the identified element otherwise after it. ''' root = container.parsed(name) nodes = root.xpath(xpath, namespaces=XPNSMAP) if not nodes: raise AbortError(_('The expression %s did not match any nodes') % xpath) for split_point in nodes: if in_table(split_point): raise AbortError('Cannot split inside tables') if split_point.tag.endswith('}body'): raise AbortError('Cannot split on the <body> tag') for i, tag in enumerate(nodes): tag.set('calibre-split-point', str(i)) current = name all_names = [name] for i in range(len(nodes)): current = split(container, current, '//*[@calibre-split-point="%d"]' % i, before=before) all_names.append(current) for x in all_names: for tag in container.parsed(x).xpath('//*[@calibre-split-point]'): tag.attrib.pop('calibre-split-point') container.dirty(x) return all_names[1:]
class MergeLinkReplacer: def __init__(self, base, anchor_map, master, container): self.container, self.anchor_map = container, anchor_map self.master = master self.base = base self.replaced = False def __call__(self, url): if url and url.startswith('#'): return url name = self.container.href_to_name(url, self.base) amap = self.anchor_map.get(name, None) if amap is None: return url purl = urlparse(url) frag = purl.fragment or '' frag = amap.get(frag, frag) url = self.container.name_to_href(self.master, self.base) + '#' + frag self.replaced = True return url def add_text(body, text): if len(body) > 0: body[-1].tail = (body[-1].tail or '') + text else: body.text = (body.text or '') + text def all_anchors(root): return set(root.xpath('//*/@id')) | set(root.xpath('//*/@name')) def all_stylesheets(container, name): for link in XPath('//h:head/h:link[@href]')(container.parsed(name)): name = container.href_to_name(link.get('href'), name) typ = link.get('type', 'text/css') if typ == 'text/css': yield name def unique_anchor(seen_anchors, current): c = 0 ans = current while ans in seen_anchors: c += 1 ans = '%s_%d' % (current, c) return ans def remove_name_attributes(root): # Remove all name attributes, replacing them with id attributes for elem in root.xpath('//*[@id and @name]'): del elem.attrib['name'] for elem in root.xpath('//*[@name]'): elem.set('id', elem.attrib.pop('name')) def merge_html(container, names, master, insert_page_breaks=False): p = container.parsed root = p(master) # Ensure master has a <head> head = root.find('h:head', namespaces=XPNSMAP) if head is None: head = root.makeelement(XHTML('head')) container.insert_into_xml(root, head, 0) seen_anchors = all_anchors(root) seen_stylesheets = set(all_stylesheets(container, master)) master_body = p(master).findall('h:body', namespaces=XPNSMAP)[-1] master_base = os.path.dirname(master) anchor_map = {n:{} for n in names if n != master} first_anchor_map = {} for name in names: if name == master: continue # Insert new stylesheets into master for sheet in all_stylesheets(container, name): if sheet not in seen_stylesheets: seen_stylesheets.add(sheet) link = head.makeelement(XHTML('link'), rel='stylesheet', type='text/css', href=container.name_to_href(sheet, master)) container.insert_into_xml(head, link) # Rebase links if master is in a different directory if os.path.dirname(name) != master_base: container.replace_links(name, LinkRebaser(container, name, master)) root = p(name) children = [] for body in p(name).findall('h:body', namespaces=XPNSMAP): children.append(body.text if body.text and body.text.strip() else '\n\n') children.extend(body) first_child = '' for first_child in children: if not isinstance(first_child, string_or_bytes): break if isinstance(first_child, string_or_bytes): # body contained only text, no tags first_child = body.makeelement(XHTML('p')) first_child.text, children[0] = children[0], first_child amap = anchor_map[name] remove_name_attributes(root) for elem in root.xpath('//*[@id]'): val = elem.get('id') if not val: continue if val in seen_anchors: nval = unique_anchor(seen_anchors, val) elem.set('id', nval) amap[val] = nval else: seen_anchors.add(val) if 'id' not in first_child.attrib: first_child.set('id', unique_anchor(seen_anchors, 'top')) seen_anchors.add(first_child.get('id')) first_anchor_map[name] = first_child.get('id') if insert_page_breaks: first_child.set('style', first_child.get('style', '') + '; page-break-before: always') amap[''] = first_child.get('id') # Fix links that point to local changed anchors for a in XPath('//h:a[starts-with(@href, "#")]')(root): q = a.get('href')[1:] if q in amap: a.set('href', '#' + amap[q]) for child in children: if isinstance(child, string_or_bytes): add_text(master_body, child) else: master_body.append(copy.deepcopy(child)) container.remove_item(name, remove_from_guide=False) # Fix all links in the container that point to merged files for fname, media_type in iteritems(container.mime_map): repl = MergeLinkReplacer(fname, anchor_map, master, container) container.replace_links(fname, repl) return first_anchor_map def merge_css(container, names, master): p = container.parsed msheet = p(master) master_base = os.path.dirname(master) merged = set() for name in names: if name == master: continue # Rebase links if master is in a different directory if os.path.dirname(name) != master_base: container.replace_links(name, LinkRebaser(container, name, master)) sheet = p(name) # Remove charset rules cr = [r for r in sheet.cssRules if r.type == r.CHARSET_RULE] [sheet.deleteRule(sheet.cssRules.index(r)) for r in cr] for rule in sheet.cssRules: msheet.add(rule) container.remove_item(name) merged.add(name) # Remove links to merged stylesheets in the html files, replacing with a # link to the master sheet for name, mt in iteritems(container.mime_map): if mt in OEB_DOCS: removed = False root = p(name) for link in XPath('//h:link[@href]')(root): q = container.href_to_name(link.get('href'), name) if q in merged: container.remove_from_xml(link) removed = True if removed: container.dirty(name) if removed and master not in set(all_stylesheets(container, name)): head = root.find('h:head', namespaces=XPNSMAP) if head is not None: link = head.makeelement(XHTML('link'), type='text/css', rel='stylesheet', href=container.name_to_href(master, name)) container.insert_into_xml(head, link)
[docs] def merge(container, category, names, master): ''' Merge the specified files into a single file, automatically migrating all links and references to the affected files. The file must all either be HTML or CSS files. :param category: Must be either ``'text'`` for HTML files or ``'styles'`` for CSS files :param names: The list of files to be merged :param master: Which of the merged files is the *master* file, that is, the file that will remain after merging. ''' if category not in {'text', 'styles'}: raise AbortError('Cannot merge files of type: %s' % category) if len(names) < 2: raise AbortError('Must specify at least two files to be merged') if master not in names: raise AbortError('The master file (%s) must be one of the files being merged' % master) if category == 'text': merge_html(container, names, master) elif category == 'styles': merge_css(container, names, master) container.dirty(master)