"""
Search Strategy for The Silver Searcher (ag)
"""
import shutil
import subprocess
from typing import Dict, List, Optional, Tuple
from .base import SearchStrategy, parse_search_output, create_safe_fuzzy_pattern
class AgStrategy(SearchStrategy):
"""Search strategy using 'The Silver Searcher' (ag) command-line tool."""
@property
def name(self) -> str:
"""The name of the search tool."""
return 'ag'
def is_available(self) -> bool:
"""Check if 'ag' command is available on the system."""
return shutil.which('ag') is not None
def search(
self,
pattern: str,
base_path: str,
case_sensitive: bool = True,
context_lines: int = 0,
file_pattern: Optional[str] = None,
fuzzy: bool = False
) -> Dict[str, List[Tuple[int, str]]]:
"""
Execute a search using The Silver Searcher (ag).
Note: ag does not support native fuzzy searching. When fuzzy=True, a
safe fuzzy pattern with word boundaries is used for regex search.
When fuzzy=False, a literal string search is performed.
"""
# ag prints line numbers and groups by file by default, which is good.
# --noheading is used to be consistent with other tools' output format.
cmd = ['ag', '--noheading']
if not case_sensitive:
cmd.append('--ignore-case')
# Prepare search pattern
search_pattern = pattern
if fuzzy:
# Use safe fuzzy pattern for regex search
search_pattern = create_safe_fuzzy_pattern(pattern)
else:
cmd.append('--literal') # or -Q
if context_lines > 0:
cmd.extend(['--before', str(context_lines)])
cmd.extend(['--after', str(context_lines)])
if file_pattern:
# Use -G to filter files by regex pattern
cmd.extend(['-G', file_pattern])
# Add -- to treat pattern as a literal argument, preventing injection
cmd.append('--')
cmd.append(search_pattern)
cmd.append(base_path)
try:
# ag exits with 1 if no matches are found, which is not an error.
# It exits with 0 on success (match found). Other codes are errors.
process = subprocess.run(
cmd,
capture_output=True,
text=True,
encoding='utf-8',
errors='replace',
check=False # Do not raise CalledProcessError on non-zero exit
)
# We don't check returncode > 1 because ag's exit code behavior
# is less standardized than rg/ug. 0 for match, 1 for no match.
# Any actual error will likely raise an exception or be in stderr.
if process.returncode > 1:
raise RuntimeError(f"ag failed with exit code {process.returncode}: {process.stderr}")
return parse_search_output(process.stdout, base_path)
except FileNotFoundError:
raise RuntimeError("'ag' (The Silver Searcher) not found. Please install it and ensure it's in your PATH.")
except Exception as e:
# Re-raise other potential exceptions like permission errors
raise RuntimeError(f"An error occurred while running ag: {e}")