Removed the Checker service, removed checker results storage (both in-memory
and the tiny stub of sqlite-based storage). Added ICheckable, all
check/verify is now done by calling the check() method on filenodes and
dirnodes (immutable files, literal files, mutable files, and directory
instances).
Checker results are returned in a Results instance, with an html() method for
display. Checker results have been temporarily removed from the wui directory
listing until we make some other fixes.
Also fixed client.create_node_from_uri() to create LiteralFileNodes properly,
since they have different checking behavior. Previously we were creating full
FileNodes with LIT uris inside, which were downloadable but not checkable.
this adds a new service to pre-generate RSA key pairs. This allows
the expensive (i.e. slow) key generation to be placed into a process
outside the node, so that the node's reactor will not block when it
needs a key pair, but instead can retrieve them from a pool of already
generated key pairs in the key-generator service.
it adds a tahoe create-key-generator command which initialises an
empty dir with a tahoe-key-generator.tac file which can then be run
via twistd. it stashes its .pem and portnum for furl stability and
writes the furl of the key gen service to key_generator.furl, also
printing it to stdout.
by placing a key_generator.furl file into the nodes config directory
(e.g. ~/.tahoe) a node will attempt to connect to such a service, and
will use that when creating mutable files (i.e. directories) whenever
possible. if the keygen service is unavailable, it will perform the
key generation locally instead, as before.
Now upload or encode methods take a required argument named "convergence" which can be either None, indicating no convergent encryption at all, or a string, which is the "added secret" to be mixed in to the content hash key. If you want traditional convergent encryption behavior, set the added secret to be the empty string.
This patch also renames "content hash key" to "convergent encryption" in a argument names and variable names. (A different and larger renaming is needed in order to clarify that Tahoe supports immutable files which are not encrypted content-hash-key a.k.a. convergent encryption.)
This patch also changes a few unit tests to use non-convergent encryption, because it doesn't matter for what they are testing and non-convergent encryption is slightly faster.
Unfinished bits: doc in webapi.txt, test handling of badly formed JSON, return reasonable HTTP response, examination of the effect of this patch on code coverage -- but I'm committing it anyway because MikeB can use it and I'm being called to dinner...
