commit 128e88e1032f93502f9b482064c7d9ce7d5eeb2a
parent 7a251be54653e684b513d008df44cefe643c18e9
Author: Carlosokumu <carlosokumu254@gmail.com>
Date: Tue, 24 Feb 2026 19:08:17 +0300
add a chain manager, alternative for managing xml files
Diffstat:
1 file changed, 158 insertions(+), 0 deletions(-)
diff --git a/dummy/usawa/core/chain_manager.py b/dummy/usawa/core/chain_manager.py
@@ -0,0 +1,157 @@
+import os
+import logging
+from usawa import Ledger, load
+from usawa.crypto import ACL, DemoWallet
+from usawa.store import LedgerStore
+from whee.valkey import ValkeyStore
+import os
+import shutil
+import logging
+
+from usawa import Ledger, load
+
+logg = logging.getLogger("core.chain_manager")
+
+
+def default_chain_dir():
+ """Return the conventional XDG data directory for usawa ledger files.
+
+ Defaults to ~/.local/share/usawa/ledger/ unless XDG_DATA_HOME is set.
+ Directory is created if it does not exist.
+ """
+ xdg_data = os.environ.get(
+ 'XDG_DATA_HOME',
+ os.path.join(os.path.expanduser('~'), '.local', 'share'),
+ )
+ path = os.path.join(xdg_data, 'usawa', 'ledger')
+ os.makedirs(path, exist_ok=True)
+ return path
+
+
+class LedgerChainManager:
+
+ def __init__(self, genesis_path=None):
+ """Initialise the chain manager.
+
+ On first ever launch, supply genesis_path so it can be copied into
+ the conventional directory as 0.xml. On subsequent launches, omit
+ genesis_path — the manager will reconstruct the chain from disk.
+
+ :param genesis_path: Path to the genesis XML file (optional after first run)
+ :type genesis_path: str or None
+ """
+ self.basedir = default_chain_dir()
+ logg.debug('chain dir: {}'.format(self.basedir))
+
+ zero = os.path.join(self.basedir, '0.xml')
+ if not os.path.exists(zero):
+ if genesis_path is None:
+ raise FileNotFoundError(
+ 'no chain found in {} and no genesis_path provided'.format(self.basedir)
+ )
+ genesis_path = os.path.realpath(genesis_path)
+ if not os.path.exists(genesis_path):
+ raise FileNotFoundError('genesis file not found: {}'.format(genesis_path))
+ shutil.copy(genesis_path, zero)
+ logg.debug('copied genesis {} → {}'.format(genesis_path, zero))
+
+ self.chain = self._reconstruct_chain()
+ logg.debug('chain reconstructed with depth {}'.format(self.depth()))
+
+
+ def _reconstruct_chain(self):
+ """Rebuild the chain list by scanning sequential xml files on disk.
+
+ Starts at 0.xml and stops at the first missing index.
+ """
+ chain = []
+ index = 0
+ while True:
+ path = os.path.join(self.basedir, '{}.xml'.format(index))
+ if not os.path.exists(path):
+ break
+ chain.append(path)
+ index += 1
+ if not chain:
+ raise FileNotFoundError('no chain files found in: {}'.format(self.basedir))
+ return chain
+
+
+ def current(self):
+ """Return the path of the most recent XML file in the chain."""
+ return self.chain[-1]
+
+
+ def derive_next(self):
+ """Derive the next output file path based on the current chain length.
+
+ genesis = index 0, first entry output = index 1, and so on.
+ """
+ next_index = len(self.chain)
+ basename = '{}.xml'.format(next_index)
+ return os.path.join(self.basedir, basename)
+
+
+ def advance(self, written_path):
+ """Call this after successfully writing an entry output file.
+
+ Verifies the file exists before appending to the chain.
+ """
+ written_path = os.path.realpath(written_path)
+ if not os.path.exists(written_path):
+ raise FileNotFoundError(
+ 'written file not found, cannot advance chain: {}'.format(written_path)
+ )
+ self.chain.append(written_path)
+ logg.debug('chain advanced to: {}'.format(written_path))
+
+
+ def load_current(self):
+ """Load and return a fresh Ledger instance from the current chain tail."""
+ ledger_path = self.current()
+ ledger_tree = load(ledger_path)
+ ledger = Ledger.from_tree(ledger_tree)
+ logg.debug('loaded ledger from: {}'.format(ledger_path))
+ return ledger
+
+
+ def write_entry(self, entry, ledger, store, wallet):
+ """Sign and write an entry, then advance the chain.
+
+ Encapsulates the full write sequence:
+ entry.sign → store.add_entry → ledger.truncate → ledger.sign → write file
+ """
+ next_path = self.derive_next()
+
+ db = ValkeyStore('')
+
+ store = LedgerStore(db, ledger)
+ pk = store.get_key()
+ wallet = DemoWallet(privatekey=pk)
+ logg.debug("wallet pk: %s pubk: %s", wallet.privkey().hex(), wallet.pubkey().hex())
+ ledger.set_wallet(wallet)
+
+
+ ledger.acl = ACL.from_wallet(wallet)
+ self.ledger = ledger
+
+ entry.sign(wallet)
+ store.add_entry(entry, update_ledger=True)
+ ledger.truncate()
+ ledger.sign()
+
+ with open(next_path, 'wb') as f:
+ f.write(ledger.to_string())
+ logg.debug('entry written to: {}'.format(next_path))
+
+ self.advance(next_path)
+ return next_path
+
+
+ def depth(self):
+ """Return the number of files in the chain including genesis."""
+ return len(self.chain)
+
+
+ def __repr__(self):
+ return 'LedgerChainManager(depth={}, current={})'.format(self.depth(), self.current())
+\ No newline at end of file
