U c@s^dZddlZddlmZmZmZmZmZmZddl m Z m Z ddl m Z mZddlmZddlmZmZdd lmZeeZd d d d dgZeee j ee j fZddZeeeddfddd Zee je jeedefddd ZedZedZ ddfeee defee gefeeeefdefddd Z!e"dfe e ee#e$ddd Z%dS)z Module defining common helpers for use by rules and policies. In principle, these aren't relevant to the high-level validation API. N)Callable GeneratorOptionalSetTupleTypeVar)genericmisc) PdfObject Reference)HistoricalResolver)ModificationLevelSuspiciousModification)ReferenceUpdatequalifysafe_whitelistcompare_key_refs compare_dictsassert_not_streamcCs"t|tjrtd|jddS)zT Throw :class:`.SuspiciousModification` if the argument is a stream object. z!Unexpected stream encountered at !N) isinstancerZ StreamObjectrZ container_ref)objrF/tmp/pip-unpacked-wheel-0kb_yl26/pyhanko/sign/diff_analysis/commons.pyrs  )oldreturnccsR|rt|||kr,t||Vn"||r>|Vntd|ddS)a~ Checks whether an indirect reference in a PDF structure can be updated without clobbering an older object in a way that causes ramifications at the PDF syntax level. The following are verified: - Does the old reference point to a non-stream object? - If the new reference is equal to the old one, does the new reference point to a non-stream object? - If the new reference is not equal to the old one, is the new reference a newly defined object? This is a generator for syntactical convenience and integration with internal APIs, but it will always yield at most one element. zUpdate clobbers or reuses z in an unexpected way.N)r get_objectZis_ref_availabler)rZold_refZnew_refrrrr&s    )rold_dictnew_dictrccsz.||}t|tjr(|j}|}nd}Wntk rJd}}YnXz.||}t|tjrt|j}|}nd}Wn.tk r|dk rtd|dYdSX|dk rt|||EdH||fS)a Ensure that updating a key in a dictionary has no undesirable side effects. The following scenarios are allowed: 0. replacing a direct value with another direct value 1. adding a key in new_dict 2. replacing a direct value in old_dict with a reference in new_dict 3. the reverse (allowed by default) 4. replacing a reference with another reference (that doesn't override anything else) The restrictions of `safe_whitelist` apply to this function as well. Note: this routine is only safe to use if the structure of the resulting values is also checked. Otherwise, it can lead to reference leaks if one is not careful. NzKey z was deleted from dictionary)NN) raw_getrrZIndirectObject referencerKeyErrorrr)keyrrr old_valueZ old_value_ref new_valueZ new_value_refrrrrGs.       RXcCs|SNr)xrrrr*)level rule_result transformrcst|fddS)aL This is a helper function for rule implementors. It attaches a fixed modification level to an existing reference update generator, respecting the original generator's return value (if relevant). A prototypical use would be of the following form: .. code-block:: python def some_generator_function(): # do stuff for ref in some_list: # do stuff yield ref # do more stuff return summary_value # ... def some_qualified_generator_function(): summary_value = yield from qualify( ModificationLevel.FORM_FILLING, some_generator_function() ) Provided that ``some_generator_function`` yields :class:`~.generic.ReferenceUpdate` objects, the yield type of the resulting generator will be tuples of the form ``(level, ref)``. :param level: The modification level to set. :param rule_result: A generator that outputs references to be whitelisted. :param transform: Function to apply to the reference object before appending the modification level and yielding it. Defaults to the identity. :return: A converted generator that outputs references qualified at the modification level specified. cs |fSr(r)refr,r.rrr*r+zqualify..)r Zmap_with_return)r,r-r.rr0rrs. T)rrignoredrc Cst|tjstdt|tjs*tdt|t|t||}t||}||kr|r~td|d|dndS|D]F}| |}| |}||kr|rtd|d|d |qdSqd S) zP Compare entries in two dictionaries, optionally ignoring certain keys. z?Encountered unexpected non-dictionary object in prior revision.z.Dict is overridden by non-dict in new revisionzDict keys differ: z vs. .FzValues for dict key z differ:z changed to T) rrDictionaryObjectr Z PdfReadErrorrrsetkeysr ) rrr1Z raise_excZ new_dict_keysZ old_dict_keysknew_valZold_valrrrrs8    )&__doc__loggingtypingrrrrrrZpyhanko.pdf_utilsrr Zpyhanko.pdf_utils.genericr r Zpyhanko.pdf_utils.readerr Z policy_apirrZ rules_apir getLogger__name__logger__all__Z TwoVersionsrrr3rr&r'r frozensetstrboolrrrrrsL      ! 4   4