"""
Context Provider — Enhanced
Retrieves code context around violation lines, extracts function signatures,
and provides symbol cross-reference search within a file.
Guards:
• Skips binary files (null-byte check)
• Caps reads at MAX_LINES to prevent memory issues
• Handles encoding errors gracefully
"""
import os
import re
import logging
from typing import List, Optional, Tuple
logger = logging.getLogger(__name__)
MAX_LINES = 100_000 # safety cap for very large files
class ContextProvider:
def __init__(self, workspace_root: str):
self.workspace_root = workspace_root
# ────────────────────────────────────────────────────────────────
# Internal helpers
# ────────────────────────────────────────────────────────────────
def _resolve(self, file_path: str) -> str:
# Normalise separators so 'src/main.c' works on Windows too
native = file_path.replace("/", os.sep).replace("\\", os.sep)
return os.path.join(self.workspace_root, native)
@staticmethod
def _read_lines(full_path: str) -> Optional[List[str]]:
"""Read file lines with binary-file guard and size cap."""
if not os.path.isfile(full_path):
return None
try:
with open(full_path, "rb") as fb:
head = fb.read(8192)
if b"\x00" in head:
logger.warning("Skipping binary file: %s", full_path)
return None
with open(full_path, "r", encoding="utf-8", errors="replace") as f:
lines = []
for i, line in enumerate(f):
if i >= MAX_LINES:
logger.warning(
"File %s exceeds %d lines — truncated", full_path, MAX_LINES
)
break
lines.append(line)
return lines
except Exception as e:
logger.error("Error reading %s: %s", full_path, e)
return None
# ────────────────────────────────────────────────────────────────
# Core: Code context around a line
# ────────────────────────────────────────────────────────────────
def get_code_context(
self, file_path: str, line_number: int, context_lines: int = 15
) -> str:
"""Retrieve code surrounding a specific line number."""
lines = self._read_lines(self._resolve(file_path))
if lines is None:
return f"Error: Cannot read {file_path}"
start = max(0, line_number - 1 - context_lines)
end = min(len(lines), line_number + context_lines)
return "".join(lines[start:end])
def get_line(self, file_path: str, line_number: int) -> str:
"""Return a single line from a file (1-indexed)."""
lines = self._read_lines(self._resolve(file_path))
if lines is None:
return ""
if 1 <= line_number <= len(lines):
return lines[line_number - 1]
return ""
# ────────────────────────────────────────────────────────────────
# Dependency analysis (includes / imports)
# ────────────────────────────────────────────────────────────────
def analyze_dependencies(self, file_path: str) -> List[str]:
"""Return all #include and import directives in a file."""
lines = self._read_lines(self._resolve(file_path))
if lines is None:
return []
deps: List[str] = []
for line in lines:
stripped = line.strip()
if stripped.startswith("#include") or stripped.startswith("import"):
deps.append(stripped)
return deps
# ────────────────────────────────────────────────────────────────
# Function signature extraction
# ────────────────────────────────────────────────────────────────
def get_enclosing_function(
self, file_path: str, line_number: int
) -> Optional[str]:
"""
Return the signature of the function enclosing 'line_number',
or None if the line is at file scope.
"""
lines = self._read_lines(self._resolve(file_path))
if lines is None:
return None
# Walk backwards from the violation line to find the function header
brace_depth = 0
for i in range(min(line_number - 1, len(lines) - 1), -1, -1):
line = lines[i]
brace_depth -= line.count("}")
brace_depth += line.count("{")
if brace_depth >= 1:
# Found the opening brace — grab the signature above
sig_lines = []
for j in range(max(0, i - 3), i + 1):
sig_lines.append(lines[j].strip())
sig = " ".join(sig_lines)
m = re.search(r"[\w\s\*]+\b(\w+)\s*\([^)]*\)", sig)
if m:
return m.group(0).strip()
break
return None
# ────────────────────────────────────────────────────────────────
# Symbol cross-reference (same file)
# ────────────────────────────────────────────────────────────────
def find_symbol_uses(
self, file_path: str, symbol: str
) -> List[Tuple[int, str]]:
"""
Find all lines in file_path that reference 'symbol'.
Returns list of (line_number, line_text).
"""
lines = self._read_lines(self._resolve(file_path))
if lines is None:
return []
results: List[Tuple[int, str]] = []
pattern = re.compile(rf"\b{re.escape(symbol)}\b")
for i, line in enumerate(lines, start=1):
if pattern.search(line):
results.append((i, line.rstrip()))
return results
