mò a&Gc@sdZdklZdklZdklZdkZdfd„ƒYZdefd„ƒYZ eƒZ e i Z e i Z e i Z e iZdS( sæ TMRegistry and ProxyTM Use case -------- Persistent objects (ExtFiles) need to participate in ZODB transactions. ExtFiles perform all operations using temporary files which are saved on commit or deleted on abort. Constraints ----------- - TransactionManagers (TM) must not be persistent themselves, i.e. must not have a _p_jar attribute. - We have to make sure the ExtFile's _abort is called *before* the ZODB destroys the attributes of the persistent object. Solution -------- - ProxyTM is a subclass of TM.TM that keeps a (hard) reference to the (wrapped) persistent object it manages. Calls to _begin, _finish, and _abort are forwarded to the target object. - TMRegistry is a module-level container for ProxyTMs. It creates and holds ProxyTMs keyed by (target_id, thread_id). - ExtFiles implement _finish and _abort and register with the machinery by calling TM.register(self). - On commit (or abort) the ProxyTM notifies its target object and removes itself from the registry. Hacks ----- - We manipulate the transaction's _resources attribute directly. This is to guarantee the ProxyTM is processed before other resources. There may be a way to achieve this using official APIs only, but I can't seem to find one. (sTM(saq_base(s get_identNt TMRegistrycBsPtZd„Zd„Zd„Zd„Zd„Zd„Zd„Zd„Z RS( NcCs h|_dS(N(tselft_tms(R((t9/home2/kennisonb/webapps/zope/Zope/Products/ExtFile/TM.pyt__init__6scCstt|ƒƒtƒfS(N(tidtaq_basettargett get_ident(RR((Rtgetid9scCsN|i|ƒp:|i|ƒ}t|ƒ}|iƒ||i|