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Edit File: visitors.pyc
� 1��fc @ s� d Z d d l m Z d d l Z d d l Z d d l m Z d d l m Z d d l m Z d d l m Z d d d d d d d d d g Z d � Z d e f d � � YZ d e j e � f d � � YZ d e f d � � YZ d � Z d e j e e � f d � � YZ d e f d � � YZ d e f d � � YZ d e f d � � YZ d e f d � � YZ e Z e Z e Z e Z e Z e j � d � Z d! � Z d" � Z d# � Z! d$ � Z" d S(% sA Visitor/traversal interface and library functions. SQLAlchemy schema and expression constructs rely on a Python-centric version of the classic "visitor" pattern as the primary way in which they apply functionality. The most common use of this pattern is statement compilation, where individual expression classes match up to rendering methods that produce a string result. Beyond this, the visitor system is also used to inspect expressions for various information and patterns, as well as for the purposes of applying transformations to expressions. Examples of how the visit system is used can be seen in the source code of for example the ``sqlalchemy.sql.util`` and the ``sqlalchemy.sql.compiler`` modules. Some background on clause adaption is also at https://techspot.zzzeek.org/2008/01/23/expression-transformations/ . i����( t dequeNi ( t exc( t util( t langhelpers( t symbolt iteratet traverse_usingt traverset cloned_traverset replacement_traverset Traversiblet TraversibleTypet ExternalTraversalt InternalTraversalc s� | j } d | j k r( | j | _ d St | t j j � sV t j d | j � � n d | } t j | � � � f d � } | | _ | _ d S( sh Generate a _compiler_dispatch() external traversal on classes with a __visit_name__ attribute. t _compiler_dispatchNs> __visit_name__ on class %s must be a string at the class levels visit_%sc sG y � | � } Wn# t k r5 } | j | | | � SX| | | � Sd S( sw Look for an attribute named "visit_<visit_name>" on the visitor, and call it with the same kw params. N( t AttributeErrort visit_unsupported_compilation( t selft visitort kwt metht err( t getter( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR G s ( t __visit_name__t __dict__R t _original_compiler_dispatcht isinstanceR t compatt string_typesR t InvalidRequestErrort __name__t operatort attrgetter( t clst visit_namet nameR ( ( R sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt _generate_compiler_dispatch0 s c B s e Z d Z d � Z RS( s9 Metaclass which assigns dispatch attributes to various kinds of "visitable" classes. Attributes include: * The ``_compiler_dispatch`` method, corresponding to ``__visit_name__``. This is called "external traversal" because the caller of each visit() method is responsible for sub-traversing the inner elements of each object. This is appropriate for string compilers and other traversals that need to call upon the inner elements in a specific pattern. * internal traversal collections ``_children_traversal``, ``_cache_key_traversal``, ``_copy_internals_traversal``, generated from an optional ``_traverse_internals`` collection of symbols which comes from the :class:`.InternalTraversal` list of symbols. This is called "internal traversal" MARKMARK c C sH | d k r( d | k r( t | � q( n t t | � j | | | � d S( NR R ( R$ t superR t __init__( R! t clsnamet basest clsdict( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR& m s ( R t __module__t __doc__R& ( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR Y s c B s2 e Z d Z d � Z e j d � d d � � Z RS( se Base class for visitable objects, applies the :class:`.visitors.TraversibleType` metaclass. c C s | S( N( ( R! t key( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt __class_getitem__{ s s sqlalchemy.sql.traversalsc si t j j } y | j } Wn t k r- g SX| j j } t j j � � f d � | | | d � D� � S( s� Return immediate child :class:`.visitors.Traversible` elements of this :class:`.visitors.Traversible`. This is used for visit traversal. \**kw may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level). c 3 s? | ]5 \ } } } | � k r | d k r | | � � Vq d S( N( t None( t .0t attrnamet objR ( R t omit_attrs( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pys <genexpr>� s t! _generated_get_children_traversal( R t preloadedt sql_traversalst _traverse_internalsR t _get_childrent run_generated_dispatcht itertoolst chaint from_iterable( R R2 R t traversalst traverse_internalst dispatch( ( R R2 sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt get_children s ( ( R R* R+ R- R t preload_moduleR? ( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR u s t _InternalTraversalTypec B s e Z d � Z RS( c C s� | j d k r� i } xq | j � D]c \ } } | j d � r" | j d d � } | j } | | k sp t | � � | | | <| | <q" q" Wt | d � r� | j | j � n | | _ n t t | � j | | | � d S( NR t ExtendedInternalTraversalt dp_t visit_t _dispatch_lookup( R RB ( R t itemst startswitht replaceR# t AssertionErrort hasattrt updateRE R% RA R& ( R! R' R( R) t lookupR, t symt visit_keyt sym_name( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR& � s ( R R* R& ( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyRA � s c C s� g } xL | D]D \ } } | j | � } | r t j | } | j | | f � q q Wd d j d � | D� � d } d | | d } t j | i | � S( Ns return [ s , c s s( | ] \ } } d | | | f Vq d S( s! (%r, self.%s, visitor.%s)N( ( R/ R0 R" ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pys <genexpr>� s s ] s def %s(self, visitor): s ( R> RB RE t appendt joinR t _exec_code_in_env( R t internal_dispatcht method_namet namesR0 t visit_symR R" t codet meth_text( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt _generate_dispatcher� s !c B s� e Z d Z d � Z d � Z d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z! e d � Z" e d � Z# e d! � Z$ e d" � Z% e d# � Z& e d$ � Z' RS(% s� Defines visitor symbols used for internal traversal. The :class:`.InternalTraversal` class is used in two ways. One is that it can serve as the superclass for an object that implements the various visit methods of the class. The other is that the symbols themselves of :class:`.InternalTraversal` are used within the ``_traverse_internals`` collection. Such as, the :class:`.Case` object defines ``_traverse_internals`` as :: _traverse_internals = [ ("value", InternalTraversal.dp_clauseelement), ("whens", InternalTraversal.dp_clauseelement_tuples), ("else_", InternalTraversal.dp_clauseelement), ] Above, the :class:`.Case` class indicates its internal state as the attributes named ``value``, ``whens``, and ``else_``. They each link to an :class:`.InternalTraversal` method which indicates the type of datastructure referred towards. Using the ``_traverse_internals`` structure, objects of type :class:`.InternalTraversible` will have the following methods automatically implemented: * :meth:`.Traversible.get_children` * :meth:`.Traversible._copy_internals` * :meth:`.Traversible._gen_cache_key` Subclasses can also implement these methods directly, particularly for the :meth:`.Traversible._copy_internals` method, when special steps are needed. .. versionadded:: 1.4 c C s | j | } t | | d � S( sq Given a method from :class:`.InternalTraversal`, return the corresponding method on a subclass. N( RE t getattrR. ( R t visit_symbolR# ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR> � s c C sM y | j j | } Wn) t k r? | j | j | | � } n X| | | � S( N( t __class__R t KeyErrort generate_dispatch( R t targetRS t generate_dispatcher_namet dispatcher( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR8 � s c C s& t | | | � } t | | | � | S( N( RY t setattr( R t target_clsRS R` Ra ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR^ s t HCt HLt CEt FCt CTSt CLt CTt EOt WCt COt St SLt ANt Bt Ot Tt PDt DOt CDt MDt AKt POt DDt PSt THt SJt MEt SHt UKt DML_OVt DML_Vt DML_MVt PA(( R R* R+ R> R8 R^ R t dp_has_cache_keyt dp_has_cache_key_listt dp_clauseelementt) dp_fromclause_canonical_column_collectiont dp_clauseelement_tuplest dp_clauseelement_listt dp_clauseelement_tuplet dp_executable_optionst dp_with_context_optionst dp_fromclause_ordered_sett dp_stringt dp_string_listt dp_anon_namet dp_booleant dp_operatort dp_typet dp_plain_dictt dp_dialect_optionst dp_string_clauseelement_dictt dp_string_multi_dictt dp_annotations_keyt dp_plain_objt dp_named_ddl_elementt dp_prefix_sequencet dp_table_hint_listt dp_setup_join_tuplet dp_memoized_select_entitiest dp_statement_hint_listt dp_unknown_structuret dp_dml_ordered_valuest dp_dml_valuest dp_dml_multi_valuest dp_propagate_attrs( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR � sL % RB c B sV e Z d Z e d � Z e d � Z e d � Z e d � Z e d � Z e d � Z RS( s[ Defines additional symbols that are useful in caching applications. Traversals for :class:`_expression.ClauseElement` objects only need to use those symbols present in :class:`.InternalTraversal`. However, for additional caching use cases within the ORM, symbols dealing with the :class:`.HasCacheKey` class are added here. t IGt ISt Mt MTt HTt IL( R R* R+ R t dp_ignoret dp_inspectablet dp_multit dp_multi_listt dp_has_cache_key_tuplest dp_inspectable_list( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyRB � s c B sY e Z d Z i Z d � Z d � Z d � Z e j d � � Z e d � � Z d � Z RS( s� Base class for visitor objects which can traverse externally using the :func:`.visitors.traverse` function. Direct usage of the :func:`.visitors.traverse` function is usually preferred. c K sD x= | j D]2 } t | d | j d � } | r | | | � Sq Wd S( Ns visit_%s( t visitor_iteratorRZ R R. ( R R1 R t vR ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt traverse_single s c C s t | | j � S( sa Traverse the given expression structure, returning an iterator of all elements. ( R t __traverse_options__( R R1 ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR s c C s t | | j | j � S( s2 Traverse and visit the given expression structure.( R R� t _visitor_dict( R R1 ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR s c C sJ i } x= t | � D]/ } | j d � r t | | � | | d <q q W| S( NRD i ( t dirRG RZ ( R t visitorsR# ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR� s c c s. | } x! | r) | Vt | d d � } q Wd S( s8 Iterate through this visitor and each 'chained' visitor.t _nextN( RZ R. ( R R� ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR� # s c C s t | j � d } | | _ | S( s� 'Chain' an additional ClauseVisitor onto this ClauseVisitor. The chained visitor will receive all visit events after this one. i����( t listR� R� ( R R t tail( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR: , s ( R R* R+ R� R� R R R t memoized_propertyR� t propertyR� R: ( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR � s t CloningExternalTraversalc B s e Z d Z d � Z d � Z RS( s� Base class for visitor objects which can traverse using the :func:`.visitors.cloned_traverse` function. Direct usage of the :func:`.visitors.cloned_traverse` function is usually preferred. c C s g | D] } | j | � ^ q S( s` Apply cloned traversal to the given list of elements, and return the new list. ( R ( R t list_t x( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt copy_and_processA s c C s t | | j | j � S( s2 Traverse and visit the given expression structure.( R R� R� ( R R1 ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR H s ( R R* R+ R� R ( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR� 7 s t ReplacingExternalTraversalc B s e Z d Z d � Z d � Z RS( s� Base class for visitor objects which can traverse using the :func:`.visitors.replacement_traverse` function. Direct usage of the :func:`.visitors.replacement_traverse` function is usually preferred. c C s d S( s Receive pre-copied elements during a cloning traversal. If the method returns a new element, the element is used instead of creating a simple copy of the element. Traversal will halt on the newly returned element if it is re-encountered. N( R. ( R t elem( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyRH Y s c s" � f d � } t | � j | � S( s2 Traverse and visit the given expression structure.c s7 x0 � j D]% } | j | � } | d k r | Sq Wd S( N( R� RH R. ( R� R� t e( R ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyRH e s ( R R� ( R R1 RH ( ( R sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR b s ( R R* R+ RH R ( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR� P s c c sv | V| j | � } | s d St | g � } xB | rq | j � } x) | D]! } | V| j | j | � � qI Wq0 Wd S( sH Traverse the given expression structure, returning an iterator. Traversal is configured to be breadth-first. The central API feature used by the :func:`.visitors.iterate` function is the :meth:`_expression.ClauseElement.get_children` method of :class:`_expression.ClauseElement` objects. This method should return all the :class:`_expression.ClauseElement` objects which are associated with a particular :class:`_expression.ClauseElement` object. For example, a :class:`.Case` structure will refer to a series of :class:`_expression.ColumnElement` objects within its "whens" and "else\_" member variables. :param obj: :class:`_expression.ClauseElement` structure to be traversed :param opts: dictionary of iteration options. This dictionary is usually empty in modern usage. N( R? R t popleftRP ( R1 t optst childrent stackt t_iteratort t( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR v s c C s= x6 | D]. } | j | j d � } | r | | � q q W| S( s� Visit the given expression structure using the given iterator of objects. :func:`.visitors.traverse_using` is usually called internally as the result of the :func:`.visitors.traverse` function. :param iterator: an iterable or sequence which will yield :class:`_expression.ClauseElement` structures; the iterator is assumed to be the product of the :func:`.visitors.iterate` function. :param obj: the :class:`_expression.ClauseElement` that was used as the target of the :func:`.iterate` function. :param visitors: dictionary of visit functions. See :func:`.traverse` for details on this dictionary. .. seealso:: :func:`.traverse` N( t getR R. ( t iteratorR1 R� R_ R ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR � s c C s t t | | � | | � S( s Traverse and visit the given expression structure using the default iterator. e.g.:: from sqlalchemy.sql import visitors stmt = select(some_table).where(some_table.c.foo == 'bar') def visit_bindparam(bind_param): print("found bound value: %s" % bind_param.value) visitors.traverse(stmt, {}, {"bindparam": visit_bindparam}) The iteration of objects uses the :func:`.visitors.iterate` function, which does a breadth-first traversal using a stack. :param obj: :class:`_expression.ClauseElement` structure to be traversed :param opts: dictionary of iteration options. This dictionary is usually empty in modern usage. :param visitors: dictionary of visit functions. The dictionary should have strings as keys, each of which would correspond to the ``__visit_name__`` of a particular kind of SQL expression object, and callable functions as values, each of which represents a visitor function for that kind of object. ( R R ( R1 R� R� ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR � s c sv i � t � j d g � � � � � f d � } � � � � f d � � | d k rl � | d | � �} n d � | S( s� Clone the given expression structure, allowing modifications by visitors. Traversal usage is the same as that of :func:`.visitors.traverse`. The visitor functions present in the ``visitors`` dictionary may also modify the internals of the given structure as the traversal proceeds. The central API feature used by the :func:`.visitors.cloned_traverse` and :func:`.visitors.replacement_traverse` functions, in addition to the :meth:`_expression.ClauseElement.get_children` function that is used to achieve the iteration, is the :meth:`_expression.ClauseElement._copy_internals` method. For a :class:`_expression.ClauseElement` structure to support cloning and replacement traversals correctly, it needs to be able to pass a cloning function into its internal members in order to make copies of them. .. seealso:: :func:`.visitors.traverse` :func:`.visitors.replacement_traverse` t stop_onc s t | � � � S( N( R ( R1 ( R� R� ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt deferred_copy_internals� s c s� | � k r | St | � � k r� d | k ra | d | � } | d k ra | � t | � <| Sn | j d � | � � t | � <} | j d � | � � j | j d � } | r� | | � q� n � t | � Sd S( NRH t clone( t idR. t _clonet _copy_internalsR� R ( R� R t newelemR ( R� t clonedR� R� ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR� � s #R� N( t setR� R. ( R1 R� R� R� ( ( R� R� R� R� R� sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR � s c sz i � d � � j d g � D� � � � f d � } � � � � f d � � | d k rp � | d | � �} n d � | S( s] Clone the given expression structure, allowing element replacement by a given replacement function. This function is very similar to the :func:`.visitors.cloned_traverse` function, except instead of being passed a dictionary of visitors, all elements are unconditionally passed into the given replace function. The replace function then has the option to return an entirely new object which will replace the one given. If it returns ``None``, then the object is kept in place. The difference in usage between :func:`.visitors.cloned_traverse` and :func:`.visitors.replacement_traverse` is that in the former case, an already-cloned object is passed to the visitor function, and the visitor function can then manipulate the internal state of the object. In the case of the latter, the visitor function should only return an entirely different object, or do nothing. The use case for :func:`.visitors.replacement_traverse` is that of replacing a FROM clause inside of a SQL structure with a different one, as is a common use case within the ORM. c S s h | ] } t | � � q S( ( R� ( R/ R� ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pys <setcomp>/ s R� c s t | � � � S( N( R ( R1 ( R� RH ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR� 1 s c s� t | � � k s! d | j k r% | S� | � } | d k rT � j t | � � | St | � } | � k r� d | k r� | d | � } | d k r� | � | <| Sn | j | � � | <} | j d � | � n � | Sd S( Nt no_replacement_traverseRH R� ( R� t _annotationsR. t addR� R� ( R� R R� t id_elem( R� R� RH R� ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR� 4 s" R� N( R� R. ( R1 R� RH R� ( ( R� R� R� RH R� sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyR s (# R+ t collectionsR R9 R t R R R R t __all__R$ t typeR t with_metaclassR RA RY t objectR RB R R� R� t Visitablet VisitableTypet ClauseVisitort CloningVisitort ReplacingCloningVisitort immutabledictR R R R R ( ( ( sJ /opt/alt/python27/lib64/python2.7/site-packages/sqlalchemy/sql/visitors.pyt <module> sJ ) + "� ): # ! <