Spaces:
Running
Running
File size: 12,483 Bytes
8755993 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 | """
Merkle Tree implementation for efficient codebase change detection.
Inspired by Cursor's approach to incremental indexing, this module builds
a cryptographic hash tree of the codebase to quickly identify which files
have changed since the last indexing operation.
"""
import hashlib
import json
import logging
import os
from dataclasses import dataclass, asdict
from pathlib import Path
from typing import Dict, List, Optional, Set
from datetime import datetime
logger = logging.getLogger(__name__)
@dataclass
class MerkleNode:
"""Represents a node in the Merkle tree (file or directory)."""
path: str # Relative path from root
hash: str # SHA-256 hash of content (or combined child hashes for directories)
is_directory: bool
size: int = 0 # File size in bytes (0 for directories)
modified_time: Optional[str] = None # ISO format timestamp
children: Optional[List['MerkleNode']] = None
def to_dict(self) -> Dict:
"""Convert to dictionary for JSON serialization."""
result = {
'path': self.path,
'hash': self.hash,
'is_directory': self.is_directory,
'size': self.size,
'modified_time': self.modified_time,
}
if self.children:
result['children'] = [child.to_dict() for child in self.children]
return result
@classmethod
def from_dict(cls, data: Dict) -> 'MerkleNode':
"""Create MerkleNode from dictionary."""
children = None
if 'children' in data and data['children']:
children = [cls.from_dict(child) for child in data['children']]
return cls(
path=data['path'],
hash=data['hash'],
is_directory=data['is_directory'],
size=data.get('size', 0),
modified_time=data.get('modified_time'),
children=children
)
@dataclass
class ChangeSet:
"""Represents changes detected between two Merkle trees."""
added: List[str] # New files
modified: List[str] # Changed files
deleted: List[str] # Removed files
unchanged: List[str] # Files that haven't changed
def has_changes(self) -> bool:
"""Check if there are any changes."""
return bool(self.added or self.modified or self.deleted)
def total_changes(self) -> int:
"""Total number of changed files."""
return len(self.added) + len(self.modified) + len(self.deleted)
def summary(self) -> str:
"""Human-readable summary of changes."""
return (
f"Added: {len(self.added)}, "
f"Modified: {len(self.modified)}, "
f"Deleted: {len(self.deleted)}, "
f"Unchanged: {len(self.unchanged)}"
)
class MerkleTree:
"""
Builds and compares Merkle trees for efficient change detection.
The tree structure mirrors the directory structure, with each node
containing a hash of its content (for files) or combined child hashes
(for directories). This allows quick identification of changes.
"""
# File extensions to ignore
IGNORE_EXTENSIONS = {
'.pyc', '.pyo', '.pyd', '.so', '.dll', '.dylib',
'.class', '.o', '.obj', '.exe', '.bin',
'.git', '.svn', '.hg', '.DS_Store',
'__pycache__', 'node_modules', '.venv', 'venv',
'.egg-info', 'dist', 'build', '.pytest_cache',
'.mypy_cache', '.tox', 'coverage', '.coverage'
}
def __init__(self, ignore_patterns: Optional[List[str]] = None):
"""
Initialize Merkle tree builder.
Args:
ignore_patterns: Additional patterns to ignore (e.g., ['*.log', 'temp/*'])
"""
self.ignore_patterns = ignore_patterns or []
def _should_ignore(self, path: Path) -> bool:
"""Check if a path should be ignored."""
# Check if any part of the path matches ignore extensions
for part in path.parts:
if part in self.IGNORE_EXTENSIONS:
return True
# Check file extension
if path.suffix in self.IGNORE_EXTENSIONS:
return True
# Check custom patterns
for pattern in self.ignore_patterns:
if path.match(pattern):
return True
return False
def _hash_file(self, file_path: Path) -> str:
"""
Compute SHA-256 hash of a file's content.
Args:
file_path: Path to the file
Returns:
Hexadecimal hash string
"""
sha256 = hashlib.sha256()
try:
with open(file_path, 'rb') as f:
# Read in chunks to handle large files
for chunk in iter(lambda: f.read(8192), b''):
sha256.update(chunk)
return sha256.hexdigest()
except Exception as e:
logger.warning(f"Failed to hash file {file_path}: {e}")
# Return a hash of the error message to ensure consistency
return hashlib.sha256(str(e).encode()).hexdigest()
def _hash_directory(self, children: List[MerkleNode]) -> str:
"""
Compute hash for a directory based on its children.
Args:
children: List of child MerkleNodes
Returns:
Combined hash of all children
"""
# Sort children by path for consistency
sorted_children = sorted(children, key=lambda x: x.path)
# Combine all child hashes
combined = ''.join(child.hash for child in sorted_children)
return hashlib.sha256(combined.encode()).hexdigest()
def build_tree(self, root_path: str) -> MerkleNode:
"""
Build a Merkle tree for the given directory.
Args:
root_path: Root directory to build tree from
Returns:
Root MerkleNode of the tree
"""
root = Path(root_path).resolve()
if not root.exists():
raise ValueError(f"Path does not exist: {root_path}")
logger.info(f"Building Merkle tree for: {root}")
return self._build_node(root, root)
def _build_node(self, path: Path, root: Path) -> MerkleNode:
"""
Recursively build a MerkleNode for a path.
Args:
path: Current path to process
root: Root directory (for computing relative paths)
Returns:
MerkleNode for this path
"""
relative_path = str(path.relative_to(root))
if path.is_file():
# File node
stat = path.stat()
return MerkleNode(
path=relative_path,
hash=self._hash_file(path),
is_directory=False,
size=stat.st_size,
modified_time=datetime.fromtimestamp(stat.st_mtime).isoformat(),
children=None
)
else:
# Directory node
children = []
try:
for child_path in sorted(path.iterdir()):
if self._should_ignore(child_path):
continue
child_node = self._build_node(child_path, root)
children.append(child_node)
except PermissionError:
logger.warning(f"Permission denied: {path}")
return MerkleNode(
path=relative_path,
hash=self._hash_directory(children),
is_directory=True,
size=0,
modified_time=None,
children=children
)
def compare_trees(self, old_tree: Optional[MerkleNode], new_tree: MerkleNode) -> ChangeSet:
"""
Compare two Merkle trees to find changes.
Args:
old_tree: Previous tree snapshot (None if first time)
new_tree: Current tree snapshot
Returns:
ChangeSet describing all changes
"""
if old_tree is None:
# First time indexing - all files are new
all_files = self._collect_all_files(new_tree)
return ChangeSet(
added=all_files,
modified=[],
deleted=[],
unchanged=[]
)
added: List[str] = []
modified: List[str] = []
deleted: List[str] = []
unchanged: List[str] = []
# Build path->node maps for efficient lookup
old_files = self._build_file_map(old_tree)
new_files = self._build_file_map(new_tree)
# Find added and modified files
for path, new_node in new_files.items():
if path not in old_files:
added.append(path)
elif old_files[path].hash != new_node.hash:
modified.append(path)
else:
unchanged.append(path)
# Find deleted files
for path in old_files:
if path not in new_files:
deleted.append(path)
change_set = ChangeSet(
added=sorted(added),
modified=sorted(modified),
deleted=sorted(deleted),
unchanged=sorted(unchanged)
)
logger.info(f"Change detection complete: {change_set.summary()}")
return change_set
def _collect_all_files(self, node: MerkleNode) -> List[str]:
"""Collect all file paths from a tree."""
files = []
if not node.is_directory:
files.append(node.path)
elif node.children:
for child in node.children:
files.extend(self._collect_all_files(child))
return files
def _build_file_map(self, node: MerkleNode) -> Dict[str, MerkleNode]:
"""Build a map of file paths to nodes."""
file_map = {}
if not node.is_directory:
file_map[node.path] = node
elif node.children:
for child in node.children:
file_map.update(self._build_file_map(child))
return file_map
def save_snapshot(self, tree: MerkleNode, snapshot_path: str):
"""
Save a Merkle tree snapshot to disk.
Args:
tree: MerkleNode to save
snapshot_path: Path to save the snapshot JSON file
"""
snapshot_file = Path(snapshot_path)
snapshot_file.parent.mkdir(parents=True, exist_ok=True)
with open(snapshot_file, 'w') as f:
json.dump(tree.to_dict(), f, indent=2)
logger.info(f"Saved Merkle tree snapshot to: {snapshot_path}")
def load_snapshot(self, snapshot_path: str) -> Optional[MerkleNode]:
"""
Load a Merkle tree snapshot from disk.
Args:
snapshot_path: Path to the snapshot JSON file
Returns:
MerkleNode or None if snapshot doesn't exist
"""
snapshot_file = Path(snapshot_path)
if not snapshot_file.exists():
logger.info(f"No snapshot found at: {snapshot_path}")
return None
try:
with open(snapshot_file, 'r') as f:
data = json.load(f)
tree = MerkleNode.from_dict(data)
logger.info(f"Loaded Merkle tree snapshot from: {snapshot_path}")
return tree
except Exception as e:
logger.error(f"Failed to load snapshot: {e}")
return None
def get_changed_files(root_path: str, snapshot_path: str) -> ChangeSet:
"""
Convenience function to detect changes since last snapshot.
Args:
root_path: Root directory of codebase
snapshot_path: Path to previous snapshot file
Returns:
ChangeSet describing all changes
"""
merkle = MerkleTree()
# Load previous snapshot
old_tree = merkle.load_snapshot(snapshot_path)
# Build current tree
new_tree = merkle.build_tree(root_path)
# Compare
changes = merkle.compare_trees(old_tree, new_tree)
# Save new snapshot
merkle.save_snapshot(new_tree, snapshot_path)
return changes
|