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filecmp.py
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"""Utilities for comparing files and directories. Classes: dircmp Functions: cmp(f1, f2, shallow=True) -> int cmpfiles(a, b, common) -> ([], [], []) clear_cache() """ import os import stat from itertools import filterfalse from types import GenericAlias __all__ = ['clear_cache', 'cmp', 'dircmp', 'cmpfiles', 'DEFAULT_IGNORES'] _cache = {} BUFSIZE = 8*1024 DEFAULT_IGNORES = [ 'RCS', 'CVS', 'tags', '.git', '.hg', '.bzr', '_darcs', '__pycache__'] def clear_cache(): """Clear the filecmp cache.""" _cache.clear() def cmp(f1, f2, shallow=True): """Compare two files. Arguments: f1 -- First file name f2 -- Second file name shallow -- treat files as identical if their stat signatures (type, size, mtime) are identical. Otherwise, files are considered different if their sizes or contents differ. [default: True] Return value: True if the files are the same, False otherwise. This function uses a cache for past comparisons and the results, with cache entries invalidated if their stat information changes. The cache may be cleared by calling clear_cache(). """ s1 = _sig(os.stat(f1)) s2 = _sig(os.stat(f2)) if s1[0] != stat.S_IFREG or s2[0] != stat.S_IFREG: return False if shallow and s1 == s2: return True if s1[1] != s2[1]: return False outcome = _cache.get((f1, f2, s1, s2)) if outcome is None: outcome = _do_cmp(f1, f2) if len(_cache) > 100: # limit the maximum size of the cache clear_cache() _cache[f1, f2, s1, s2] = outcome return outcome def _sig(st): return (stat.S_IFMT(st.st_mode), st.st_size, st.st_mtime) def _do_cmp(f1, f2): bufsize = BUFSIZE with open(f1, 'rb') as fp1, open(f2, 'rb') as fp2: while True: b1 = fp1.read(bufsize) b2 = fp2.read(bufsize) if b1 != b2: return False if not b1: return True # Directory comparison class. # class dircmp: """A class that manages the comparison of 2 directories. dircmp(a, b, ignore=None, hide=None) A and B are directories. IGNORE is a list of names to ignore, defaults to DEFAULT_IGNORES. HIDE is a list of names to hide, defaults to [os.curdir, os.pardir]. High level usage: x = dircmp(dir1, dir2) x.report() -> prints a report on the differences between dir1 and dir2 or x.report_partial_closure() -> prints report on differences between dir1 and dir2, and reports on common immediate subdirectories. x.report_full_closure() -> like report_partial_closure, but fully recursive. Attributes: left_list, right_list: The files in dir1 and dir2, filtered by hide and ignore. common: a list of names in both dir1 and dir2. left_only, right_only: names only in dir1, dir2. common_dirs: subdirectories in both dir1 and dir2. common_files: files in both dir1 and dir2. common_funny: names in both dir1 and dir2 where the type differs between dir1 and dir2, or the name is not stat-able. same_files: list of identical files. diff_files: list of filenames which differ. funny_files: list of files which could not be compared. subdirs: a dictionary of dircmp instances (or MyDirCmp instances if this object is of type MyDirCmp, a subclass of dircmp), keyed by names in common_dirs. """ def __init__(self, a, b, ignore=None, hide=None): # Initialize self.left = a self.right = b if hide is None: self.hide = [os.curdir, os.pardir] # Names never to be shown else: self.hide = hide if ignore is None: self.ignore = DEFAULT_IGNORES else: self.ignore = ignore def phase0(self): # Compare everything except common subdirectories self.left_list = _filter(os.listdir(self.left), self.hide+self.ignore) self.right_list = _filter(os.listdir(self.right), self.hide+self.ignore) self.left_list.sort() self.right_list.sort() def phase1(self): # Compute common names a = dict(zip(map(os.path.normcase, self.left_list), self.left_list)) b = dict(zip(map(os.path.normcase, self.right_list), self.right_list)) self.common = list(map(a.__getitem__, filter(b.__contains__, a))) self.left_only = list(map(a.__getitem__, filterfalse(b.__contains__, a))) self.right_only = list(map(b.__getitem__, filterfalse(a.__contains__, b))) def phase2(self): # Distinguish files, directories, funnies self.common_dirs = [] self.common_files = [] self.common_funny = [] for x in self.common: a_path = os.path.join(self.left, x) b_path = os.path.join(self.right, x) ok = 1 try: a_stat = os.stat(a_path) except OSError: # print('Can\'t stat', a_path, ':', why.args[1]) ok = 0 try: b_stat = os.stat(b_path) except OSError: # print('Can\'t stat', b_path, ':', why.args[1]) ok = 0 if ok: a_type = stat.S_IFMT(a_stat.st_mode) b_type = stat.S_IFMT(b_stat.st_mode) if a_type != b_type: self.common_funny.append(x) elif stat.S_ISDIR(a_type): self.common_dirs.append(x) elif stat.S_ISREG(a_type): self.common_files.append(x) else: self.common_funny.append(x) else: self.common_funny.append(x) def phase3(self): # Find out differences between common files xx = cmpfiles(self.left, self.right, self.common_files) self.same_files, self.diff_files, self.funny_files = xx def phase4(self): # Find out differences between common subdirectories # A new dircmp (or MyDirCmp if dircmp was subclassed) object is created # for each common subdirectory, # these are stored in a dictionary indexed by filename. # The hide and ignore properties are inherited from the parent self.subdirs = {} for x in self.common_dirs: a_x = os.path.join(self.left, x) b_x = os.path.join(self.right, x) self.subdirs[x] = self.__class__(a_x, b_x, self.ignore, self.hide) def phase4_closure(self): # Recursively call phase4() on subdirectories self.phase4() for sd in self.subdirs.values(): sd.phase4_closure() def report(self): # Print a report on the differences between a and b # Output format is purposely lousy print('diff', self.left, self.right) if self.left_only: self.left_only.sort() print('Only in', self.left, ':', self.left_only) if self.right_only: self.right_only.sort() print('Only in', self.right, ':', self.right_only) if self.same_files: self.same_files.sort() print('Identical files :', self.same_files) if self.diff_files: self.diff_files.sort() print('Differing files :', self.diff_files) if self.funny_files: self.funny_files.sort() print('Trouble with common files :', self.funny_files) if self.common_dirs: self.common_dirs.sort() print('Common subdirectories :', self.common_dirs) if self.common_funny: self.common_funny.sort() print('Common funny cases :', self.common_funny) def report_partial_closure(self): # Print reports on self and on subdirs self.report() for sd in self.subdirs.values(): print() sd.report() def report_full_closure(self): # Report on self and subdirs recursively self.report() for sd in self.subdirs.values(): print() sd.report_full_closure() methodmap = dict(subdirs=phase4, same_files=phase3, diff_files=phase3, funny_files=phase3, common_dirs = phase2, common_files=phase2, common_funny=phase2, common=phase1, left_only=phase1, right_only=phase1, left_list=phase0, right_list=phase0) def __getattr__(self, attr): if attr not in self.methodmap: raise AttributeError(attr) self.methodmap[attr](self) return getattr(self, attr) __class_getitem__ = classmethod(GenericAlias) def cmpfiles(a, b, common, shallow=True): """Compare common files in two directories. a, b -- directory names common -- list of file names found in both directories shallow -- if true, do comparison based solely on stat() information Returns a tuple of three lists: files that compare equal files that are different filenames that aren't regular files. """ res = ([], [], []) for x in common: ax = os.path.join(a, x) bx = os.path.join(b, x) res[_cmp(ax, bx, shallow)].append(x) return res # Compare two files. # Return: # 0 for equal # 1 for different # 2 for funny cases (can't stat, etc.) # def _cmp(a, b, sh, abs=abs, cmp=cmp): try: return not abs(cmp(a, b, sh)) except OSError: return 2 # Return a copy with items that occur in skip removed. # def _filter(flist, skip): return list(filterfalse(skip.__contains__, flist)) # Demonstration and testing. # def demo(): import sys import getopt options, args = getopt.getopt(sys.argv[1:], 'r') if len(args) != 2: raise getopt.GetoptError('need exactly two args', None) dd = dircmp(args[0], args[1]) if ('-r', '') in options: dd.report_full_closure() else: dd.report() if __name__ == '__main__': demo()