view tests/test-flagprocessor.t @ 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.

# Create server
  $ hg init server
  $ cd server
  $ cat >> .hg/hgrc << EOF
  > [extensions]
  > extension=$TESTDIR/flagprocessorext.py
  > EOF
  $ cd ../

# Clone server and enable extensions
  $ hg clone -q server client
  $ cd client
  $ cat >> .hg/hgrc << EOF
  > [extensions]
  > extension=$TESTDIR/flagprocessorext.py
  > EOF

# Commit file that will trigger the noop extension
  $ echo '[NOOP]' > noop
  $ hg commit -Aqm "noop"

# Commit file that will trigger the base64 extension
  $ echo '[BASE64]' > base64
  $ hg commit -Aqm 'base64'

# Commit file that will trigger the gzip extension
  $ echo '[GZIP]' > gzip
  $ hg commit -Aqm 'gzip'

# Commit file that will trigger noop and base64
  $ echo '[NOOP][BASE64]' > noop-base64
  $ hg commit -Aqm 'noop+base64'

# Commit file that will trigger noop and gzip
  $ echo '[NOOP][GZIP]' > noop-gzip
  $ hg commit -Aqm 'noop+gzip'

# Commit file that will trigger base64 and gzip
  $ echo '[BASE64][GZIP]' > base64-gzip
  $ hg commit -Aqm 'base64+gzip'

# Commit file that will trigger base64, gzip and noop
  $ echo '[BASE64][GZIP][NOOP]' > base64-gzip-noop
  $ hg commit -Aqm 'base64+gzip+noop'

# TEST: ensure the revision data is consistent
  $ hg cat noop
  [NOOP]
  $ hg debugdata noop 0
  [NOOP]

  $ hg cat -r . base64
  [BASE64]
  $ hg debugdata base64 0
  W0JBU0U2NF0K (no-eol)

  $ hg cat -r . gzip
  [GZIP]
  $ hg debugdata gzip 0
  x\x9c\x8bv\x8f\xf2\x0c\x88\xe5\x02\x00\x08\xc8\x01\xfd (no-eol) (esc)

  $ hg cat -r . noop-base64
  [NOOP][BASE64]
  $ hg debugdata noop-base64 0
  W05PT1BdW0JBU0U2NF0K (no-eol)

  $ hg cat -r . noop-gzip
  [NOOP][GZIP]
  $ hg debugdata noop-gzip 0
  x\x9c\x8b\xf6\xf3\xf7\x0f\x88\x8dv\x8f\xf2\x0c\x88\xe5\x02\x00\x1dH\x03\xf1 (no-eol) (esc)

  $ hg cat -r . base64-gzip
  [BASE64][GZIP]
  $ hg debugdata base64-gzip 0
  eJyLdnIMdjUziY12j/IMiOUCACLBBDo= (no-eol)

  $ hg cat -r . base64-gzip-noop
  [BASE64][GZIP][NOOP]
  $ hg debugdata base64-gzip-noop 0
  eJyLdnIMdjUziY12j/IMiI328/cPiOUCAESjBi4= (no-eol)

# Push to the server
  $ hg push
  pushing to $TESTTMP/server (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 7 changesets with 7 changes to 7 files

# Initialize new client (not cloning) and setup extension
  $ cd ..
  $ hg init client2
  $ cd client2
  $ cat >> .hg/hgrc << EOF
  > [paths]
  > default = $TESTTMP/server
  > [extensions]
  > extension=$TESTDIR/flagprocessorext.py
  > EOF

# Pull from server and update to latest revision
  $ hg pull default
  pulling from $TESTTMP/server (glob)
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 7 changesets with 7 changes to 7 files
  (run 'hg update' to get a working copy)
  $ hg update
  7 files updated, 0 files merged, 0 files removed, 0 files unresolved

# TEST: ensure the revision data is consistent
  $ hg cat noop
  [NOOP]
  $ hg debugdata noop 0
  [NOOP]

  $ hg cat -r . base64
  [BASE64]
  $ hg debugdata base64 0
  W0JBU0U2NF0K (no-eol)

  $ hg cat -r . gzip
  [GZIP]
  $ hg debugdata gzip 0
  x\x9c\x8bv\x8f\xf2\x0c\x88\xe5\x02\x00\x08\xc8\x01\xfd (no-eol) (esc)

  $ hg cat -r . noop-base64
  [NOOP][BASE64]
  $ hg debugdata noop-base64 0
  W05PT1BdW0JBU0U2NF0K (no-eol)

  $ hg cat -r . noop-gzip
  [NOOP][GZIP]
  $ hg debugdata noop-gzip 0
  x\x9c\x8b\xf6\xf3\xf7\x0f\x88\x8dv\x8f\xf2\x0c\x88\xe5\x02\x00\x1dH\x03\xf1 (no-eol) (esc)

  $ hg cat -r . base64-gzip
  [BASE64][GZIP]
  $ hg debugdata base64-gzip 0
  eJyLdnIMdjUziY12j/IMiOUCACLBBDo= (no-eol)

  $ hg cat -r . base64-gzip-noop
  [BASE64][GZIP][NOOP]
  $ hg debugdata base64-gzip-noop 0
  eJyLdnIMdjUziY12j/IMiI328/cPiOUCAESjBi4= (no-eol)

# TEST: ensure a missing processor is handled
  $ echo '[FAIL][BASE64][GZIP][NOOP]' > fail-base64-gzip-noop
  $ hg commit -Aqm 'fail+base64+gzip+noop'
  abort: missing processor for flag '0x1'!
  [255]

# TEST: ensure we cannot register several flag processors on the same flag
  $ cat >> .hg/hgrc << EOF
  > [extensions]
  > extension=$TESTDIR/flagprocessorext.py
  > duplicate=$TESTDIR/flagprocessorext.py
  > EOF
  $ echo 'this should fail' > file
  $ hg commit -Aqm 'add file'
  abort: cannot register multiple processors on flag '0x8'.
  [255]