141 lines
6.1 KiB
Python
141 lines
6.1 KiB
Python
"""
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Basic glob match implementation for starlark.
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This was originally developed by @jbedard for use in rules_js
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(https://github.com/aspect-build/rules_js/blob/6ca32d5199ddc0bf19bd704f591030dc1468ca5f/npm/private/pkg_glob.bzl)
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to support the pnpm public-hoist-expr option (https://pnpm.io/npmrc#public-hoist-expr). The pnpm
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implementation and tests were used as a reference implementation:
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https://github.com/pnpm/pnpm/blob/v7.4.0-2/packages/matcher/src/index.ts
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https://github.com/pnpm/pnpm/blob/v7.4.0-2/packages/matcher/test/index.ts
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"""
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def _split_on(expr, splits):
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# Splits an expression on the tokens in splits but keeps the tokens split in the result.
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# Tokens are matched in order so a token such as `**` should come before `*`.
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result = []
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accumulator = ""
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skip = 0
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for i in range(len(expr)):
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j = i + skip
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if j >= len(expr):
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break
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for split in splits:
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if not split:
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fail("empty split token")
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if expr[j:].startswith(split):
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if accumulator:
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result.append(accumulator)
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accumulator = ""
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result.append(split)
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skip = skip + len(split)
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j = i + skip
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break
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if j >= len(expr):
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break
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accumulator = accumulator + expr[j]
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if accumulator:
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result.append(accumulator)
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return result
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def glob_match(expr, path, match_path_separator = False):
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"""Test if the passed path matches the glob expression.
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`*` A single asterisk stands for zero or more arbitrary characters except for the the path separator `/` if `match_path_separator` is False
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`?` The question mark stands for exactly one character except for the the path separator `/` if `match_path_separator` is False
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`**` A double asterisk stands for an arbitrary sequence of 0 or more characters. It is only allowed when preceded by either the beginning of the string or a slash. Likewise it must be followed by a slash or the end of the pattern.
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Args:
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expr: the glob expression
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path: the path against which to match the glob expression
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match_path_separator: whether or not to match the path separator '/' when matching `*` and `?` expressions
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Returns:
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True if the path matches the glob expression
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"""
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expr_i = 0
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path_i = 0
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if expr.find("***") != -1:
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fail("glob_match: invalid *** pattern found in glob expression")
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expr_parts = _split_on(expr, ["**", "*", "?"])
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for i, expr_part in enumerate(expr_parts):
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if expr_part == "**":
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if i > 0 and not expr_parts[i - 1].endswith("/"):
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msg = "glob_match: `**` globstar in expression `{}` must be at the start of the expression or preceeded by `/`".format(expr)
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fail(msg)
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if i != len(expr_parts) - 1 and not expr_parts[i + 1].startswith("/"):
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msg = "glob_match: `**` globstar in expression `{}` must be at the end of the expression or followed by `/`".format(expr)
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fail(msg)
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# Locations a * was terminated that can be rolled back to.
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branches = []
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# Loop "forever" (2^30).
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for _ in range(1073741824):
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subpath = path[path_i:] if path_i < len(path) else None
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subexpr = expr_parts[expr_i] if expr_i < len(expr_parts) else None
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# The next part of the expression.
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next_pp = expr_parts[expr_i + 1] if expr_i + 1 < len(expr_parts) else None
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stop_at_leading_path_separator = not match_path_separator and subpath != None and subpath.startswith("/")
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stop_at_contained_path_separator = not match_path_separator and subpath != None and subpath.find("/") != -1
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if (subexpr == "*" and subpath != None and not stop_at_leading_path_separator) or (subexpr == "**" and subpath != None):
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# A wildcard or globstar in the expression and something to consume.
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if next_pp == None and not stop_at_contained_path_separator:
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# This wildcard is the last and matches everything beyond here.
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return True
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# If the next part of the expression matches the current subpath
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# then advance past the wildcard and consume that next expression.
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if next_pp != None and subpath.startswith(next_pp):
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# Persist the alternative of using the wildcard instead of advancing.
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branches.append([expr_i, path_i + 1])
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expr_i = expr_i + 1
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else:
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# Otherwise consume the next character.
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path_i = path_i + 1
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elif subexpr == "*" and subpath != None and stop_at_leading_path_separator and next_pp != None and subpath.startswith(next_pp):
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# A wildcard that has hit a path separator but we can branch
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# Persist the alternative of using the wildcard instead of advancing.
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branches.append([expr_i, path_i + 1])
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expr_i = expr_i + 1
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elif subexpr == "?" and subpath != None and not stop_at_leading_path_separator:
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# The string matches a ? wildcard at the current location in the path.
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expr_i = expr_i + 1
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path_i = path_i + 1
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elif subexpr and subpath != None and subpath.startswith(subexpr):
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# The string matches the current location in the path.
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expr_i = expr_i + 1
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path_i = path_i + len(subexpr)
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elif subpath == None and expr_i == len(expr_parts) - 1 and (subexpr == "*" or subexpr == "**"):
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# Reached the package on a final empty "*" or "**" expression
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return True
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elif len(branches) > 0:
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# The string does not match, backup to the previous branch.
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[restored_pattern_i, restored_path_i] = branches.pop()
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path_i = restored_path_i
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expr_i = restored_pattern_i
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else:
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# The string does not match, with no branches to rollback to, there is no match.
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return False
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if path_i == len(path) and expr_i == len(expr_parts):
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# Reached the end of the expression and package.
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return True
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fail("glob_match: reached the end of the (in)finite loop")
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