853 lines
28 KiB
Python
853 lines
28 KiB
Python
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import difflib
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from django.core.exceptions import ImproperlyConfigured
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from django.db import models
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from django.utils.encoding import force_str
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from django.utils.html import escape, format_html, format_html_join
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from django.utils.safestring import mark_safe
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from django.utils.text import capfirst
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from django.utils.translation import gettext_lazy as _
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from taggit.managers import TaggableManager
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from wagtail import blocks
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from wagtail.fields import RichTextField, StreamField
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from wagtail.utils.registry import ModelFieldRegistry
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from wagtail.utils.text import text_from_html
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comparison_class_registry = ModelFieldRegistry()
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def register_comparison_class(
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field_class, to=None, comparison_class=None, exact_class=False
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):
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"""
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Define parameters for form fields to be used by WagtailAdminModelForm for a given
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database field.
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"""
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if comparison_class is None:
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raise ImproperlyConfigured(
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"register_comparison_class must be passed a 'comparison_class' keyword argument"
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)
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if to and field_class != models.ForeignKey:
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raise ImproperlyConfigured(
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"The 'to' argument on register_comparison_class is only valid for ForeignKey fields"
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)
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comparison_class_registry.register(
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field_class, to=to, value=comparison_class, exact_class=exact_class
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)
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class FieldComparison:
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is_field = True
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is_child_relation = False
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def __init__(self, field, obj_a, obj_b):
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self.field = field
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self.val_a = field.value_from_object(obj_a)
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self.val_b = field.value_from_object(obj_b)
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def field_label(self):
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"""
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Returns a label for this field to be displayed to the user
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"""
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verbose_name = getattr(self.field, "verbose_name", None)
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if verbose_name is None:
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# Relations don't have a verbose_name
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verbose_name = self.field.name.replace("_", " ")
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return capfirst(verbose_name)
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def htmldiff(self):
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if self.val_a != self.val_b:
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return TextDiff(
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[("deletion", self.val_a), ("addition", self.val_b)]
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).to_html()
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else:
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return escape(self.val_a)
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def has_changed(self):
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"""
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Returns True if the field has changed
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"""
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return self.val_a != self.val_b
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class TextFieldComparison(FieldComparison):
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def htmldiff(self):
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return diff_text(self.val_a, self.val_b).to_html()
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register_comparison_class(models.CharField, comparison_class=TextFieldComparison)
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register_comparison_class(models.TextField, comparison_class=TextFieldComparison)
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class RichTextFieldComparison(TextFieldComparison):
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def htmldiff(self):
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return diff_text(
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text_from_html(self.val_a), text_from_html(self.val_b)
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).to_html()
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register_comparison_class(RichTextField, comparison_class=RichTextFieldComparison)
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def get_comparison_class_for_block(block):
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if hasattr(block, "get_comparison_class"):
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return block.get_comparison_class()
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elif isinstance(block, (blocks.CharBlock, blocks.TextBlock)):
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return CharBlockComparison
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elif isinstance(block, blocks.RawHTMLBlock):
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# Compare raw HTML blocks as if they were plain text, so that tags are shown explicitly
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return CharBlockComparison
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elif isinstance(block, blocks.RichTextBlock):
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return RichTextBlockComparison
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elif isinstance(block, blocks.StructBlock):
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return StructBlockComparison
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elif isinstance(block, blocks.StreamBlock):
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return StreamBlockComparison
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elif isinstance(block, blocks.ListBlock):
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return ListBlockComparison
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else:
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# As all stream field blocks have a HTML representation, fall back to diffing that.
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return RichTextBlockComparison
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class BlockComparison:
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def __init__(self, block, exists_a, exists_b, val_a, val_b):
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self.block = block
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self.exists_a = exists_a
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self.exists_b = exists_b
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self.val_a = val_a
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self.val_b = val_b
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def is_new(self):
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return self.exists_b and not self.exists_a
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def is_deleted(self):
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return self.exists_a and not self.exists_b
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def has_changed(self):
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return self.val_a != self.val_b
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def htmlvalue(self, val):
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"""
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Return an HTML representation of this block that is safe to be included
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in comparison views
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"""
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return escape(text_from_html(self.block.render_basic(val)))
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def htmldiff(self):
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html_val_a = self.block.render_basic(self.val_a)
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html_val_b = self.block.render_basic(self.val_b)
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return diff_text(
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text_from_html(html_val_a), text_from_html(html_val_b)
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).to_html()
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class CharBlockComparison(BlockComparison):
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def htmldiff(self):
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return diff_text(force_str(self.val_a), force_str(self.val_b)).to_html()
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def htmlvalue(self, val):
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return escape(val)
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class RichTextBlockComparison(BlockComparison):
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pass
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class StructBlockComparison(BlockComparison):
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def htmlvalue(self, val):
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htmlvalues = []
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for name, block in self.block.child_blocks.items():
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label = self.block.child_blocks[name].label
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comparison_class = get_comparison_class_for_block(block)
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htmlvalues.append(
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(
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label,
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comparison_class(block, True, True, val[name], val[name]).htmlvalue(
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val[name]
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),
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)
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)
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return format_html(
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"<dl>\n{}\n</dl>",
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format_html_join("\n", " <dt>{}</dt>\n <dd>{}</dd>", htmlvalues),
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)
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def htmldiff(self):
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htmldiffs = []
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for name, block in self.block.child_blocks.items():
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label = self.block.child_blocks[name].label
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comparison_class = get_comparison_class_for_block(block)
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htmldiffs.append(
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(
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label,
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comparison_class(
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block,
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self.exists_a,
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self.exists_b,
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self.val_a[name],
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self.val_b[name],
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).htmldiff(),
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)
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)
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return format_html(
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"<dl>\n{}\n</dl>",
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format_html_join("\n", " <dt>{}</dt>\n <dd>{}</dd>", htmldiffs),
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)
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class BaseSequenceBlockComparison(BlockComparison):
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@staticmethod
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def get_blocks_from_value(val):
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raise NotImplementedError
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@staticmethod
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def get_blocks_by_id(a_blocks, b_blocks):
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a_blocks_by_id = {block.id: block for block in a_blocks}
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b_blocks_by_id = {block.id: block for block in b_blocks}
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return a_blocks_by_id, b_blocks_by_id
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def get_block_comparisons_by_id(self):
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a_blocks = self.get_blocks_from_value(self.val_a)
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b_blocks = self.get_blocks_from_value(self.val_b)
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a_blocks_by_id, b_blocks_by_id = self.get_blocks_by_id(a_blocks, b_blocks)
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deleted_ids = a_blocks_by_id.keys() - b_blocks_by_id.keys()
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comparisons = []
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for block in b_blocks:
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comparison_class = get_comparison_class_for_block(block.block)
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if block.id in a_blocks_by_id:
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# Changed/existing block
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comparisons.append(
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comparison_class(
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block.block,
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True,
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True,
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a_blocks_by_id[block.id].value,
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block.value,
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)
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)
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else:
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# New block
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comparisons.append(
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comparison_class(block.block, False, True, None, block.value)
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)
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# Insert deleted blocks at the index where they used to be
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deleted_block_indices = [
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(block, i) for i, block in enumerate(a_blocks) if block.id in deleted_ids
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]
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for block, index in deleted_block_indices:
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comparison_class = get_comparison_class_for_block(block.block)
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comparison_to_insert = comparison_class(
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block.block, True, False, block.value, None
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)
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# Insert the block back in where it was before it was deleted.
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# Note: we need to account for new blocks when finding the position.
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current_index = 0
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block_inserted = False
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for i, comparison in enumerate(comparisons):
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if comparison.is_new():
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continue
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if current_index == index:
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comparisons.insert(i, comparison_to_insert)
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block_inserted = True
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break
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current_index += 1
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# Deleted block was from the end
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if not block_inserted:
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comparisons.append(comparison_to_insert)
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return comparisons
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def htmldiff(self):
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comparisons_html = []
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for comparison in self.get_block_comparisons():
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classes = ["comparison__child-object"]
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if comparison.is_new():
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classes.append("addition")
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block_rendered = comparison.htmlvalue(comparison.val_b)
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elif comparison.is_deleted():
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classes.append("deletion")
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block_rendered = comparison.htmlvalue(comparison.val_a)
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elif comparison.has_changed():
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block_rendered = comparison.htmldiff()
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else:
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block_rendered = comparison.htmlvalue(comparison.val_a)
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classes = " ".join(classes)
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comparisons_html.append(f'<div class="{classes}">{block_rendered}</div>')
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return mark_safe("\n".join(comparisons_html))
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class StreamBlockComparison(BaseSequenceBlockComparison):
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@staticmethod
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def get_blocks_from_value(val):
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blocks = list(val) or []
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return blocks
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def get_block_comparisons(self):
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return self.get_block_comparisons_by_id()
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class ListBlockComparison(BaseSequenceBlockComparison):
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@staticmethod
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def get_blocks_from_value(val):
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blocks = list(val.bound_blocks) or []
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return blocks
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def get_block_comparisons(self):
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a_blocks = self.get_blocks_from_value(self.val_a)
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b_blocks = self.get_blocks_from_value(self.val_b)
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# ListBlock could be in one of two formats.
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# If IDs in both a and b are all newly created (ie we're loading data in the old format)
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# there's no point in using id for identifying which blocks are the same vs moved / added / deleted.
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both_in_new_format = any(block.original_id for block in a_blocks) and any(
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block.original_id for block in b_blocks
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)
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if both_in_new_format:
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# All blocks have ids, so we can use the BaseSequenceBlock comparison logic, which uses ids.
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return self.get_block_comparisons_by_id()
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# We're dealing with data in the old format
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# Let's compare blocks by position - it's not perfect, but it's better than rendering to HTML
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comparisons = []
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comparison_class = get_comparison_class_for_block(self.block.child_block)
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a_length = len(a_blocks)
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b_length = len(b_blocks)
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for index, block in enumerate(b_blocks):
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if index < a_length:
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# Assume blocks with the same index are the same changed block
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# (not necessarily true as blocks could be moved)
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# Changed/existing block
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comparisons.append(
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comparison_class(
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block.block,
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True,
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True,
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a_blocks[index].value,
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block.value,
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)
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)
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else:
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# New block
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comparisons.append(
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comparison_class(block.block, False, True, None, block.value)
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)
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if a_length > b_length:
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for block in a_blocks[b_length:]:
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# Deleted blocks
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comparisons.append(
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comparison_class(block.block, True, False, block.value, None)
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)
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return comparisons
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class StreamFieldComparison(FieldComparison):
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def has_block_ids(self, val):
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if not val:
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return True
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return bool(val[0].id)
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def htmldiff(self):
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# Our method for diffing streamfields relies on the blocks in both revisions having UUIDs.
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# But as UUIDs were added in Wagtail 1.11 we can't compare revisions that were created before
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# that Wagtail version.
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if self.has_block_ids(self.val_a) and self.has_block_ids(self.val_b):
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return StreamBlockComparison(
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self.field.stream_block, True, True, self.val_a, self.val_b
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).htmldiff()
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else:
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# Fall back to diffing the HTML representation
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|
|
return diff_text(
|
||
|
|
text_from_html(self.val_a), text_from_html(self.val_b)
|
||
|
|
).to_html()
|
||
|
|
|
||
|
|
|
||
|
|
register_comparison_class(StreamField, comparison_class=StreamFieldComparison)
|
||
|
|
|
||
|
|
|
||
|
|
class ChoiceFieldComparison(FieldComparison):
|
||
|
|
def htmldiff(self):
|
||
|
|
val_a = force_str(
|
||
|
|
dict(self.field.flatchoices).get(self.val_a, self.val_a), strings_only=True
|
||
|
|
)
|
||
|
|
val_b = force_str(
|
||
|
|
dict(self.field.flatchoices).get(self.val_b, self.val_b), strings_only=True
|
||
|
|
)
|
||
|
|
|
||
|
|
if self.val_a != self.val_b:
|
||
|
|
diffs = []
|
||
|
|
|
||
|
|
if val_a:
|
||
|
|
diffs += [("deletion", val_a)]
|
||
|
|
if val_b:
|
||
|
|
diffs += [("addition", val_b)]
|
||
|
|
|
||
|
|
return TextDiff(diffs).to_html()
|
||
|
|
else:
|
||
|
|
return escape(val_a)
|
||
|
|
|
||
|
|
|
||
|
|
class M2MFieldComparison(FieldComparison):
|
||
|
|
def get_items(self):
|
||
|
|
return list(self.val_a), list(self.val_b)
|
||
|
|
|
||
|
|
def get_item_display(self, item):
|
||
|
|
return str(item)
|
||
|
|
|
||
|
|
def htmldiff(self):
|
||
|
|
# Get tags
|
||
|
|
items_a, items_b = self.get_items()
|
||
|
|
|
||
|
|
# Calculate changes
|
||
|
|
sm = difflib.SequenceMatcher(0, items_a, items_b)
|
||
|
|
changes = []
|
||
|
|
for op, i1, i2, j1, j2 in sm.get_opcodes():
|
||
|
|
if op == "replace":
|
||
|
|
for item in items_a[i1:i2]:
|
||
|
|
changes.append(("deletion", self.get_item_display(item)))
|
||
|
|
for item in items_b[j1:j2]:
|
||
|
|
changes.append(("addition", self.get_item_display(item)))
|
||
|
|
elif op == "delete":
|
||
|
|
for item in items_a[i1:i2]:
|
||
|
|
changes.append(("deletion", self.get_item_display(item)))
|
||
|
|
elif op == "insert":
|
||
|
|
for item in items_b[j1:j2]:
|
||
|
|
changes.append(("addition", self.get_item_display(item)))
|
||
|
|
elif op == "equal":
|
||
|
|
for item in items_a[i1:i2]:
|
||
|
|
changes.append(("equal", self.get_item_display(item)))
|
||
|
|
|
||
|
|
# Convert changelist to HTML
|
||
|
|
return TextDiff(changes, separator=", ").to_html()
|
||
|
|
|
||
|
|
def has_changed(self):
|
||
|
|
items_a, items_b = self.get_items()
|
||
|
|
return items_a != items_b
|
||
|
|
|
||
|
|
|
||
|
|
class TagsFieldComparison(M2MFieldComparison):
|
||
|
|
def get_item_display(self, tag):
|
||
|
|
return tag.slug
|
||
|
|
|
||
|
|
|
||
|
|
register_comparison_class(TaggableManager, comparison_class=TagsFieldComparison)
|
||
|
|
|
||
|
|
|
||
|
|
class ForeignObjectComparison(FieldComparison):
|
||
|
|
def get_objects(self):
|
||
|
|
model = self.field.related_model
|
||
|
|
obj_a = model.objects.filter(pk=self.val_a).first()
|
||
|
|
obj_b = model.objects.filter(pk=self.val_b).first()
|
||
|
|
return obj_a, obj_b
|
||
|
|
|
||
|
|
def htmldiff(self):
|
||
|
|
obj_a, obj_b = self.get_objects()
|
||
|
|
|
||
|
|
if obj_a != obj_b:
|
||
|
|
if obj_a and obj_b:
|
||
|
|
# Changed
|
||
|
|
return TextDiff(
|
||
|
|
[("deletion", force_str(obj_a)), ("addition", force_str(obj_b))]
|
||
|
|
).to_html()
|
||
|
|
elif obj_b:
|
||
|
|
# Added
|
||
|
|
return TextDiff([("addition", force_str(obj_b))]).to_html()
|
||
|
|
elif obj_a:
|
||
|
|
# Removed
|
||
|
|
return TextDiff([("deletion", force_str(obj_a))]).to_html()
|
||
|
|
else:
|
||
|
|
if obj_a:
|
||
|
|
return escape(force_str(obj_a))
|
||
|
|
else:
|
||
|
|
return _("None")
|
||
|
|
|
||
|
|
|
||
|
|
class ChildRelationComparison:
|
||
|
|
is_field = False
|
||
|
|
is_child_relation = True
|
||
|
|
|
||
|
|
def __init__(self, field, field_comparisons, obj_a, obj_b, label=""):
|
||
|
|
self.field = field
|
||
|
|
self.field_comparisons = field_comparisons
|
||
|
|
self.val_a = getattr(obj_a, field.related_name)
|
||
|
|
self.val_b = getattr(obj_b, field.related_name)
|
||
|
|
self.label = label
|
||
|
|
|
||
|
|
def field_label(self):
|
||
|
|
"""
|
||
|
|
Returns a label for this field to be displayed to the user
|
||
|
|
"""
|
||
|
|
verbose_name = getattr(self.field, "verbose_name", None)
|
||
|
|
|
||
|
|
if verbose_name is None:
|
||
|
|
# Relations don't have a verbose_name
|
||
|
|
if self.label:
|
||
|
|
# If the panel has a label, we set it instead.
|
||
|
|
# See InlinePanel.get_comparison for usage
|
||
|
|
verbose_name = self.label
|
||
|
|
else:
|
||
|
|
verbose_name = self.field.name.replace("_", " ")
|
||
|
|
|
||
|
|
return capfirst(verbose_name)
|
||
|
|
|
||
|
|
def get_mapping(self, objs_a, objs_b):
|
||
|
|
"""
|
||
|
|
This bit of code attempts to match the objects in the A revision with
|
||
|
|
their counterpart in the B revision.
|
||
|
|
|
||
|
|
A match is firstly attempted by PK (where a matching ID indicates they're the same).
|
||
|
|
We compare remaining the objects by their field data; the objects with the fewest
|
||
|
|
fields changed are matched until there are no more possible matches left.
|
||
|
|
|
||
|
|
This returns 4 values:
|
||
|
|
- map_forwards => a mapping of object indexes from the B version to the A version
|
||
|
|
- map_backwards => a mapping of object indexes from the A version to the B version
|
||
|
|
- added => a list of indices for objects that didn't exist in the B version
|
||
|
|
- deleted => a list of indices for objects that didn't exist in the A version
|
||
|
|
|
||
|
|
Note the indices are 0-based array indices indicating the location of the object in either
|
||
|
|
the objs_a or objs_b arrays.
|
||
|
|
|
||
|
|
For example:
|
||
|
|
|
||
|
|
objs_a => A, B, C, D
|
||
|
|
objs_b => B, C, D, E
|
||
|
|
|
||
|
|
Will return the following:
|
||
|
|
|
||
|
|
map_forwards = {
|
||
|
|
1: 0, # B (objs_a: objs_b)
|
||
|
|
2: 1, # C (objs_a: objs_b)
|
||
|
|
3: 2, # D (objs_a: objs_b)
|
||
|
|
}
|
||
|
|
map_backwards = {
|
||
|
|
0: 1, # B (objs_b: objs_a)
|
||
|
|
1: 2, # C (objs_b: objs_a)
|
||
|
|
2: 3, # D (objs_b: objs_a)
|
||
|
|
}
|
||
|
|
added = [4] # D in objs_b
|
||
|
|
deleted = [0] # A in objs_a
|
||
|
|
"""
|
||
|
|
map_forwards = {}
|
||
|
|
map_backwards = {}
|
||
|
|
added = []
|
||
|
|
deleted = []
|
||
|
|
|
||
|
|
# Match child objects on PK (ID)
|
||
|
|
for a_idx, a_child in enumerate(objs_a):
|
||
|
|
for b_idx, b_child in enumerate(objs_b):
|
||
|
|
if b_idx in map_backwards:
|
||
|
|
continue
|
||
|
|
|
||
|
|
if (
|
||
|
|
a_child.pk is not None
|
||
|
|
and b_child.pk is not None
|
||
|
|
and a_child.pk == b_child.pk
|
||
|
|
):
|
||
|
|
map_forwards[a_idx] = b_idx
|
||
|
|
map_backwards[b_idx] = a_idx
|
||
|
|
|
||
|
|
# Now try to match them by data
|
||
|
|
matches = []
|
||
|
|
for a_idx, a_child in enumerate(objs_a):
|
||
|
|
if a_idx not in map_forwards:
|
||
|
|
for b_idx, b_child in enumerate(objs_b):
|
||
|
|
if b_idx not in map_backwards:
|
||
|
|
# If they both have a PK (ID) that is different, they can't be the same child object
|
||
|
|
if a_child.pk and b_child.pk and a_child.pk != b_child.pk:
|
||
|
|
continue
|
||
|
|
|
||
|
|
comparison = self.get_child_comparison(
|
||
|
|
objs_a[a_idx], objs_b[b_idx]
|
||
|
|
)
|
||
|
|
num_differences = comparison.get_num_differences()
|
||
|
|
|
||
|
|
matches.append((a_idx, b_idx, num_differences))
|
||
|
|
|
||
|
|
# Objects with the least differences will be matched first. So only the best possible matches are made
|
||
|
|
matches.sort(key=lambda match: match[2])
|
||
|
|
for a_idx, b_idx, num_differences in matches:
|
||
|
|
# Make sure both objects were not matched previously
|
||
|
|
if a_idx in map_forwards or b_idx in map_backwards:
|
||
|
|
continue
|
||
|
|
|
||
|
|
# Match!
|
||
|
|
map_forwards[a_idx] = b_idx
|
||
|
|
map_backwards[b_idx] = a_idx
|
||
|
|
|
||
|
|
# Mark unmapped objects as added/deleted
|
||
|
|
for a_idx, a_child in enumerate(objs_a):
|
||
|
|
if a_idx not in map_forwards:
|
||
|
|
deleted.append(a_idx)
|
||
|
|
|
||
|
|
for b_idx, b_child in enumerate(objs_b):
|
||
|
|
if b_idx not in map_backwards:
|
||
|
|
added.append(b_idx)
|
||
|
|
|
||
|
|
return map_forwards, map_backwards, added, deleted
|
||
|
|
|
||
|
|
def get_child_comparison(self, obj_a, obj_b):
|
||
|
|
return ChildObjectComparison(
|
||
|
|
self.field.related_model, self.field_comparisons, obj_a, obj_b
|
||
|
|
)
|
||
|
|
|
||
|
|
def get_child_comparisons(self):
|
||
|
|
"""
|
||
|
|
Returns a list of ChildObjectComparison objects. Representing all child
|
||
|
|
objects that existed in either version.
|
||
|
|
|
||
|
|
They are returned in the order they appear in the B version with deletions
|
||
|
|
appended at the end.
|
||
|
|
|
||
|
|
All child objects are returned, regardless of whether they were actually changed.
|
||
|
|
"""
|
||
|
|
objs_a = list(self.val_a.all())
|
||
|
|
objs_b = list(self.val_b.all())
|
||
|
|
|
||
|
|
map_forwards, map_backwards, added, deleted = self.get_mapping(objs_a, objs_b)
|
||
|
|
objs_a = dict(enumerate(objs_a))
|
||
|
|
objs_b = dict(enumerate(objs_b))
|
||
|
|
|
||
|
|
comparisons = []
|
||
|
|
|
||
|
|
for b_idx, b_child in objs_b.items():
|
||
|
|
if b_idx in added:
|
||
|
|
comparisons.append(self.get_child_comparison(None, b_child))
|
||
|
|
else:
|
||
|
|
comparisons.append(
|
||
|
|
self.get_child_comparison(objs_a[map_backwards[b_idx]], b_child)
|
||
|
|
)
|
||
|
|
|
||
|
|
for a_idx, a_child in objs_a.items():
|
||
|
|
if a_idx in deleted:
|
||
|
|
comparisons.append(self.get_child_comparison(a_child, None))
|
||
|
|
|
||
|
|
return comparisons
|
||
|
|
|
||
|
|
def has_changed(self):
|
||
|
|
"""
|
||
|
|
Returns true if any changes were made to any of the child objects. This includes
|
||
|
|
adding, deleting and reordering.
|
||
|
|
"""
|
||
|
|
objs_a = list(self.val_a.all())
|
||
|
|
objs_b = list(self.val_b.all())
|
||
|
|
|
||
|
|
map_forwards, map_backwards, added, deleted = self.get_mapping(objs_a, objs_b)
|
||
|
|
|
||
|
|
if added or deleted:
|
||
|
|
return True
|
||
|
|
|
||
|
|
for a_idx, b_idx in map_forwards.items():
|
||
|
|
comparison = self.get_child_comparison(objs_a[a_idx], objs_b[b_idx])
|
||
|
|
|
||
|
|
if comparison.has_changed():
|
||
|
|
return True
|
||
|
|
|
||
|
|
return False
|
||
|
|
|
||
|
|
|
||
|
|
class ChildObjectComparison:
|
||
|
|
def __init__(self, model, field_comparisons, obj_a, obj_b):
|
||
|
|
self.model = model
|
||
|
|
self.field_comparisons = field_comparisons
|
||
|
|
self.obj_a = obj_a
|
||
|
|
self.obj_b = obj_b
|
||
|
|
|
||
|
|
def is_addition(self):
|
||
|
|
"""
|
||
|
|
Returns True if this child object was created since obj_a
|
||
|
|
"""
|
||
|
|
return self.obj_b and not self.obj_a
|
||
|
|
|
||
|
|
def is_deletion(self):
|
||
|
|
"""
|
||
|
|
Returns True if this child object was deleted in obj_b
|
||
|
|
"""
|
||
|
|
return self.obj_a and not self.obj_b
|
||
|
|
|
||
|
|
def get_position_change(self):
|
||
|
|
"""
|
||
|
|
Returns the change in position as an integer. Positive if the object
|
||
|
|
was moved down, negative if it moved up.
|
||
|
|
|
||
|
|
For example: '3' indicates the object moved down three spaces. '-1'
|
||
|
|
indicates the object moved up one space.
|
||
|
|
"""
|
||
|
|
if not self.is_addition() and not self.is_deletion():
|
||
|
|
sort_a = getattr(self.obj_a, "sort_order", 0) or 0
|
||
|
|
sort_b = getattr(self.obj_b, "sort_order", 0) or 0
|
||
|
|
return sort_b - sort_a
|
||
|
|
|
||
|
|
def get_field_comparisons(self):
|
||
|
|
"""
|
||
|
|
Returns a list of comparisons for all the fields in this object.
|
||
|
|
Fields that haven't changed are included as well.
|
||
|
|
"""
|
||
|
|
comparisons = []
|
||
|
|
|
||
|
|
if self.is_addition() or self.is_deletion():
|
||
|
|
# Display the fields without diff as one of the versions are missing
|
||
|
|
obj = self.obj_a or self.obj_b
|
||
|
|
|
||
|
|
for field_comparison in self.field_comparisons:
|
||
|
|
comparisons.append(field_comparison(obj, obj))
|
||
|
|
else:
|
||
|
|
for field_comparison in self.field_comparisons:
|
||
|
|
comparisons.append(field_comparison(self.obj_a, self.obj_b))
|
||
|
|
|
||
|
|
return comparisons
|
||
|
|
|
||
|
|
def has_changed(self):
|
||
|
|
for comparison in self.get_field_comparisons():
|
||
|
|
if comparison.has_changed():
|
||
|
|
return True
|
||
|
|
|
||
|
|
return False
|
||
|
|
|
||
|
|
def get_num_differences(self):
|
||
|
|
"""
|
||
|
|
Returns the number of fields that differ between the two
|
||
|
|
objects.
|
||
|
|
"""
|
||
|
|
num_differences = 0
|
||
|
|
|
||
|
|
for comparison in self.get_field_comparisons():
|
||
|
|
if comparison.has_changed():
|
||
|
|
num_differences += 1
|
||
|
|
|
||
|
|
return num_differences
|
||
|
|
|
||
|
|
|
||
|
|
class TextDiff:
|
||
|
|
def __init__(self, changes, separator=""):
|
||
|
|
self.changes = changes
|
||
|
|
self.separator = separator
|
||
|
|
|
||
|
|
def to_html(self, tag="span", addition_class="addition", deletion_class="deletion"):
|
||
|
|
html = []
|
||
|
|
|
||
|
|
for change_type, value in self.changes:
|
||
|
|
if change_type == "equal":
|
||
|
|
html.append(escape(value))
|
||
|
|
elif change_type == "addition":
|
||
|
|
html.append(
|
||
|
|
'<{tag} class="{classname}">{value}</{tag}>'.format(
|
||
|
|
tag=tag, classname=addition_class, value=escape(value)
|
||
|
|
)
|
||
|
|
)
|
||
|
|
elif change_type == "deletion":
|
||
|
|
html.append(
|
||
|
|
'<{tag} class="{classname}">{value}</{tag}>'.format(
|
||
|
|
tag=tag, classname=deletion_class, value=escape(value)
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
return mark_safe(self.separator.join(html))
|
||
|
|
|
||
|
|
|
||
|
|
def diff_text(a, b):
|
||
|
|
"""
|
||
|
|
Performs a diffing algorithm on two pieces of text. Returns
|
||
|
|
a string of HTML containing the content of both texts with
|
||
|
|
<span> tags inserted indicating where the differences are.
|
||
|
|
"""
|
||
|
|
|
||
|
|
def tokenise(text):
|
||
|
|
"""
|
||
|
|
Tokenises a string by splitting it into individual characters
|
||
|
|
and grouping the alphanumeric ones together.
|
||
|
|
|
||
|
|
This means that punctuation, whitespace, CJK characters, etc
|
||
|
|
become separate tokens and words/numbers are merged together
|
||
|
|
to form bigger tokens.
|
||
|
|
|
||
|
|
This makes the output of the diff easier to read as words are
|
||
|
|
not broken up.
|
||
|
|
"""
|
||
|
|
tokens = []
|
||
|
|
current_token = ""
|
||
|
|
|
||
|
|
for c in text or "":
|
||
|
|
if c.isalnum():
|
||
|
|
current_token += c
|
||
|
|
else:
|
||
|
|
if current_token:
|
||
|
|
tokens.append(current_token)
|
||
|
|
current_token = ""
|
||
|
|
|
||
|
|
tokens.append(c)
|
||
|
|
|
||
|
|
if current_token:
|
||
|
|
tokens.append(current_token)
|
||
|
|
|
||
|
|
return tokens
|
||
|
|
|
||
|
|
a_tok = tokenise(a)
|
||
|
|
b_tok = tokenise(b)
|
||
|
|
sm = difflib.SequenceMatcher(lambda t: len(t) <= 4, a_tok, b_tok)
|
||
|
|
|
||
|
|
changes = []
|
||
|
|
|
||
|
|
for op, i1, i2, j1, j2 in sm.get_opcodes():
|
||
|
|
if op == "replace":
|
||
|
|
for token in a_tok[i1:i2]:
|
||
|
|
changes.append(("deletion", token))
|
||
|
|
for token in b_tok[j1:j2]:
|
||
|
|
changes.append(("addition", token))
|
||
|
|
elif op == "delete":
|
||
|
|
for token in a_tok[i1:i2]:
|
||
|
|
changes.append(("deletion", token))
|
||
|
|
elif op == "insert":
|
||
|
|
for token in b_tok[j1:j2]:
|
||
|
|
changes.append(("addition", token))
|
||
|
|
elif op == "equal":
|
||
|
|
for token in a_tok[i1:i2]:
|
||
|
|
changes.append(("equal", token))
|
||
|
|
|
||
|
|
# Merge adjacent changes which have the same type. This just cleans up the HTML a bit
|
||
|
|
merged_changes = []
|
||
|
|
current_value = []
|
||
|
|
current_change_type = None
|
||
|
|
for change_type, value in changes:
|
||
|
|
if change_type != current_change_type:
|
||
|
|
if current_change_type is not None:
|
||
|
|
merged_changes.append((current_change_type, "".join(current_value)))
|
||
|
|
current_value = []
|
||
|
|
|
||
|
|
current_change_type = change_type
|
||
|
|
|
||
|
|
current_value.append(value)
|
||
|
|
|
||
|
|
if current_value:
|
||
|
|
merged_changes.append((current_change_type, "".join(current_value)))
|
||
|
|
|
||
|
|
return TextDiff(merged_changes)
|