view tests/test-filecache.py.out @ 30745:c1b7b2285522

revlog: flag processor

Add the ability for revlog objects to process revision flags and apply
registered transforms on read/write operations.

This patch introduces:
- the 'revlog._processflags()' method that looks at revision flags and applies
  flag processors registered on them. Due to the need to handle non-commutative
  operations, flag transforms are applied in stable order but the order in which
  the transforms are applied is reversed between read and write operations.
- the 'addflagprocessor()' method allowing to register processors on flags.
  Flag processors are defined as a 3-tuple of (read, write, raw) functions to be
  applied depending on the operation being performed.
- an update on 'revlog.addrevision()' behavior. The current flagprocessor design
  relies on extensions to wrap around 'addrevision()' to set flags on revision
  data, and on the flagprocessor to perform the actual transformation of its
  contents. In the lfs case, this means we need to process flags before we meet
  the 2GB size check, leading to performing some operations before it happens:
  - if flags are set on the revision data, we assume some extensions might be
    modifying the contents using the flag processor next, and we compute the
    node for the original revision data (still allowing extension to override
    the node by wrapping around 'addrevision()').
  - we then invoke the flag processor to apply registered transforms (in lfs's
    case, drastically reducing the size of large blobs).
  - finally, we proceed with the 2GB size check.

Note: In the case a cachedelta is passed to 'addrevision()' and we detect the
flag processor modified the revision data, we chose to trust the flag processor
and drop the cachedelta.

basic:

* neither file exists
creating
* neither file still exists
* empty file x created
creating
* file x changed size
creating
* nothing changed with either file
* file x changed inode
creating
* empty file y created
creating
* file y changed size
creating
* file y changed inode
creating
* both files changed inode
creating

fakeuncacheable:

* neither file exists
creating
* neither file still exists
creating
* empty file x created
creating
* file x changed size
creating
* nothing changed with either file
creating
* file x changed inode
creating
* empty file y created
creating
* file y changed size
creating
* file y changed inode
creating
* both files changed inode
creating
repository tip rolled back to revision -1 (undo commit)
working directory now based on revision -1
repository tip rolled back to revision -1 (undo commit)
working directory now based on revision -1

setbeforeget:

* neither file exists
string set externally
* file x created
creating
string from function
* string set externally again
string 2 set externally
* file y created
creating
string from function

antiambiguity: