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110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
// Copyright (c) Meta Platforms, Inc. and affiliates.
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// SPDX-License-Identifier: GPL-3.0-or-later
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/**
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* @file
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*
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* Paths.
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*
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* See @ref Paths.
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*/
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#ifndef DRGN_PATH_H
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#define DRGN_PATH_H
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#include <elfutils/libdw.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include "nstring.h" // IWYU pragma: export
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/**
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* @ingroup Internals
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*
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* @defgroup Paths Paths
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*
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* Utilities for working with paths.
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*
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* @{
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*/
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/**
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* Path component iterator.
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*
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* This iterates over the components of a file path, joining multiple components
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* and normalizing the result. Normalization:
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*
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* - Collapses redundant "/" separators.
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* - Removes "." components.
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* - Removes ".." components when possible.
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*
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* Components are emitted in @b reverse. So, "a/b/c" is emitted in the order
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* "c", "b", "a" (this allows the implementation to operate in O(n) time and
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* O(1) space).
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*
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* Absolute paths have an implicit empty component, so "/a/b" is emitted as "b",
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* "a", "".
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*
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* Relative paths are emitted relative to a hypothetical current directory. A
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* path referring to the current directory (e.g., "." or "a/..") does not emit
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* any components.
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*
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* ".." components above the current directory are included, so "a/b/../../../c"
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* is emitted as "c", "..". However, ".." components above an absolute path are
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* not meaningful, so "/a/b/../../../c" is emitted as "c", "".
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*
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* A empty path does not emit any components.
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*/
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struct path_iterator {
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/**
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* Array of input components.
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*
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* The input components are treated as if they were joined with a "/".
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* @ref nstring::str and @ref nstring::len should be initialized for
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* each component. The latter will be modified as the path is iterated.
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*/
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struct nstring *components;
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/** Number of components in @ref path_iterator::components. */
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size_t num_components;
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/**
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* Current number of ".." components.
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*
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* Initialize this to 0.
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*/
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size_t dot_dot;
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};
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/**
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* Get the next component from a @ref path_iterator.
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*
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* Components are emitted in reverse. This will never emit a "." component. It
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* will emit an empty ("") component only for an absolute path. It may emit ".."
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* components if there are any that go above the current directory.
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*
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* @param[in] it Iterator.
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* @param[out] component_ret Returned component.
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* @param[out] component_len_ret Length of @c component.
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* @return @c true if we returned a componenent, @c false if there were no more
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* components.
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*/
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bool path_iterator_next(struct path_iterator *it, const char **component_ret,
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size_t *component_len_ret);
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/**
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* Return whether the path @p haystack ends with the path @p needle once both
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* are normalized.
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*
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* The unit of comparison is a path component, not a character. Thus, "ab/cd/ef"
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* ends with "cd/ef", but not "d/ef".
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*
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* @sa path_iterator
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*/
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bool path_ends_with(struct path_iterator *haystack,
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struct path_iterator *needle);
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bool die_matches_filename(Dwarf_Die *die, const char *filename);
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/** @} */
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#endif /* DRGN_PATH_H */
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