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Diffstat (limited to 'libbutl/filesystem.hxx')
| -rw-r--r-- | libbutl/filesystem.hxx | 567 |
1 files changed, 567 insertions, 0 deletions
diff --git a/libbutl/filesystem.hxx b/libbutl/filesystem.hxx new file mode 100644 index 0000000..bf1b3af --- /dev/null +++ b/libbutl/filesystem.hxx @@ -0,0 +1,567 @@ +// file : libbutl/filesystem.hxx -*- C++ -*- +// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd +// license : MIT; see accompanying LICENSE file + +#ifndef LIBBUTL_FILESYSTEM_HXX +#define LIBBUTL_FILESYSTEM_HXX + +#ifndef _WIN32 +# include <dirent.h> // DIR +#else +# include <stddef.h> // intptr_t +#endif + +// VC's sys/types.h header file doesn't define mode_t type. So let's define it +// ourselves according to the POSIX specification. +// +#ifndef _MSC_VER +# include <sys/types.h> // mode_t +#else + typedef int mode_t; +#endif + +#include <cstddef> // ptrdiff_t +#include <cstdint> // uint16_t +#include <utility> // move(), pair +#include <iterator> +#include <functional> + +#include <libbutl/export.hxx> + +#include <libbutl/path.hxx> +#include <libbutl/timestamp.hxx> + +namespace butl +{ + // Return true if the path is to an existing regular file. Note that by + // default this function follows symlinks. + // + LIBBUTL_EXPORT bool + file_exists (const char*, bool follow_symlinks = true); + + inline bool + file_exists (const path& p, bool fs = true) { + return file_exists (p.string ().c_str (), fs);} + + // Return true if the path is to an existing directory. Note that this + // function follows symlinks. + // + LIBBUTL_EXPORT bool + dir_exists (const char*); + + inline bool + dir_exists (const path& p) {return dir_exists (p.string ().c_str ());} + + // Return true if the path is to an existing file system entry. Note that by + // default this function doesn't follow symlinks. + // + LIBBUTL_EXPORT bool + entry_exists (const char*, bool follow_symlinks = false); + + inline bool + entry_exists (const path& p, bool fs = false) { + return entry_exists (p.string ().c_str (), fs);} + + // Filesystem entry type. + // + enum class entry_type + { + unknown, + regular, + directory, + symlink, + other + }; + + // Return a flag indicating if the path is to an existing file system entry + // and its type if so. Note that by default this function doesn't follow + // symlinks. + // + LIBBUTL_EXPORT std::pair<bool, entry_type> + path_entry (const char*, bool follow_symlinks = false); + + inline std::pair<bool, entry_type> + path_entry (const path& p, bool fs = false) { + return path_entry (p.string ().c_str (), fs);} + + // Return true if the directory is empty. Note that the path must exist + // and be a directory. + // + LIBBUTL_EXPORT bool + dir_empty (const dir_path&); + + // Try to create a directory unless it already exists. If you expect + // the directory to exist and performance is important, then you + // should first call dir_exists() above since that's what this + // implementation will do to make sure the path is actually a + // directory. + // + // You should also probably use the default mode 0777 and let the + // umask mechanism adjust it to the user's preferences. + // + // Errors are reported by throwing std::system_error. + // + enum class mkdir_status {success, already_exists}; + + LIBBUTL_EXPORT mkdir_status + try_mkdir (const dir_path&, mode_t = 0777); + + // The '-p' version of the above (i.e., it creates the parent + // directories if necessary). + // + LIBBUTL_EXPORT mkdir_status + try_mkdir_p (const dir_path&, mode_t = 0777); + + // Try to remove the directory returning not_exist if it does not exist + // and not_empty if it is not empty. Unless ignore_error is true, all + // other errors are reported by throwing std::system_error. + // + enum class rmdir_status {success, not_exist, not_empty}; + + LIBBUTL_EXPORT rmdir_status + try_rmdir (const dir_path&, bool ignore_error = false); + + // The '-r' (recursive) version of the above. Note that it will + // never return not_empty. + // + LIBBUTL_EXPORT rmdir_status + try_rmdir_r (const dir_path&, bool ignore_error = false); + + // As above but throws rather than returns not_exist if the directory + // does not exist (unless ignore_error is true), so check before calling. + // If the second argument is false, then the directory itself is not removed. + // + LIBBUTL_EXPORT void + rmdir_r (const dir_path&, bool dir = true, bool ignore_error = false); + + // Try to remove the file (or symlinks) returning not_exist if + // it does not exist. Unless ignore_error is true, all other + // errors are reported by throwing std::system_error. + // + enum class rmfile_status {success, not_exist}; + + LIBBUTL_EXPORT rmfile_status + try_rmfile (const path&, bool ignore_error = false); + + // Automatically try to remove the path on destruction unless cancelled. + // Since the non-cancelled destruction will normally happen as a result + // of an exception, the failure to remove the path is silently ignored. + // + template <typename P> + struct auto_rm + { + explicit + auto_rm (P p = P ()): path_ (std::move (p)) {} + + void + cancel () {path_ = P ();} + + const P& + path () const {return path_;} + + // Movable-only type. Move-assignment cancels the lhs object. + // + auto_rm (auto_rm&&); + auto_rm& operator= (auto_rm&&); + auto_rm (const auto_rm&) = delete; + auto_rm& operator= (const auto_rm&) = delete; + + ~auto_rm (); + + private: + P path_; + }; + + using auto_rmfile = auto_rm<path>; + using auto_rmdir = auto_rm<dir_path>; // Note: recursive (rm_r). + + // Create a symbolic link to a file (default) or directory (third argument + // is true). Throw std::system_error on failures. + // + // Note that Windows symlinks are currently not supported. + // + LIBBUTL_EXPORT void + mksymlink (const path& target, const path& link, bool dir = false); + + // Create a symbolic link to a directory. Throw std::system_error on + // failures. + // + inline void + mksymlink (const dir_path& target, const dir_path& link) + { + mksymlink (target, link, true); + } + + // Create a hard link to a file (default) or directory (third argument is + // true). Throw std::system_error on failures. + // + // Note that on Linix, FreeBSD and some other platforms the target can not + // be a directory. While Windows support directories (via junktions), this + // is currently not implemented. + // + LIBBUTL_EXPORT void + mkhardlink (const path& target, const path& link, bool dir = false); + + // Create a hard link to a directory. Throw std::system_error on failures. + // + inline void + mkhardlink (const dir_path& target, const dir_path& link) + { + mkhardlink (target, link, true); + } + + // File copy flags. + // + enum class cpflags: std::uint16_t + { + overwrite_content = 0x1, + overwrite_permissions = 0x2, + + none = 0 + }; + + inline cpflags operator& (cpflags, cpflags); + inline cpflags operator| (cpflags, cpflags); + inline cpflags operator&= (cpflags&, cpflags); + inline cpflags operator|= (cpflags&, cpflags); + + // Copy a regular file, including its permissions. Throw std::system_error + // on failure. Fail if the destination file exists and the overwrite_content + // flag is not set. Leave permissions of an existing destination file intact + // unless the overwrite_permissions flag is set. Delete incomplete copies + // before throwing. + // + // Note that in case of overwriting, the existing destination file gets + // truncated (not deleted) prior to being overwritten. As a side-effect, + // hard link to the destination file will still reference the same file + // system node after the copy. + // + // Also note that if the overwrite_content flag is not set and the + // destination is a dangling symbolic link, then this function will still + // fail. + // + LIBBUTL_EXPORT void + cpfile (const path& from, const path& to, cpflags = cpflags::none); + + // Copy a regular file into (inside) an existing directory. + // + inline void + cpfile_into (const path& from, + const dir_path& into, + cpflags fl = cpflags::none) + { + cpfile (from, into / from.leaf (), fl); + } + + // Rename a filesystem entry (file, symlink, or directory). Throw + // std::system_error on failure. + // + // If the source path refers to a directory, then the destination path must + // either not exist, or refer to an empty directory. If the source path + // refers to an entry that is not a directory, then the destination path must + // not exist or not refer to a directory. + // + // If the source path refers to a symlink, then the link is renamed. If the + // destination path refers to a symlink, then the link will be overwritten. + // + // If the source and destination paths are on different file systems (or + // different drives on Windows) and the underlying OS does not support move + // for the source entry, then fail unless the source paths refers to a file + // or a file symlink. In this case fall back to copying the source file + // (content, permissions, access and modification times) and removing the + // source entry afterwards. + // + // Note that the operation is atomic only on POSIX, only if source and + // destination paths are on the same file system, and only if the + // overwrite_content flag is specified. + // + LIBBUTL_EXPORT void + mventry (const path& from, + const path& to, + cpflags = cpflags::overwrite_permissions); + + // Move a filesystem entry into (inside) an existing directory. + // + inline void + mventry_into (const path& from, + const dir_path& into, + cpflags f = cpflags::overwrite_permissions) + { + mventry (from, into / from.leaf (), f); + } + + // Raname file or file symlink. + // + inline void + mvfile (const path& from, + const path& to, + cpflags f = cpflags::overwrite_permissions) + { + mventry (from, to, f); + } + + inline void + mvfile_into (const path& from, + const dir_path& into, + cpflags f = cpflags::overwrite_permissions) + { + mventry_into (from, into, f); + } + + // Raname directory or directory symlink. + // + inline void + mvdir (const dir_path& from, + const dir_path& to, + cpflags f = cpflags::overwrite_permissions) + { + mventry (from, to, f); + } + + inline void + mvdir_into (const path& from, + const dir_path& into, + cpflags f = cpflags::overwrite_permissions) + { + mventry_into (from, into, f); + } + + // Return timestamp_nonexistent if the entry at the specified path + // does not exist or is not a path. All other errors are reported + // by throwing std::system_error. Note that this function resolves + // symlinks. + // + LIBBUTL_EXPORT timestamp + file_mtime (const char*); + + inline timestamp + file_mtime (const path& p) {return file_mtime (p.string ().c_str ());} + + // Path permissions. + // + enum class permissions: std::uint16_t + { + // Note: matching POSIX values. + // + xo = 0001, + wo = 0002, + ro = 0004, + + xg = 0010, + wg = 0020, + rg = 0040, + + xu = 0100, + wu = 0200, + ru = 0400, + + none = 0 + }; + + inline permissions operator& (permissions, permissions); + inline permissions operator| (permissions, permissions); + inline permissions operator&= (permissions&, permissions); + inline permissions operator|= (permissions&, permissions); + + // Get path permissions. Throw std::system_error on failure. Note that this + // function resolves symlinks. + // + LIBBUTL_EXPORT permissions + path_permissions (const path&); + + // Set path permissions. Throw std::system_error on failure. Note that this + // function resolves symlinks. + // + LIBBUTL_EXPORT void + path_permissions (const path&, permissions); + + // Directory entry iteration. + // + class LIBBUTL_EXPORT dir_entry + { + public: + typedef butl::path path_type; + + // Symlink target type in case of the symlink, ltype() otherwise. + // + entry_type + type () const; + + entry_type + ltype () const; + + // Entry path (excluding the base). To get the full path, do + // base () / path (). + // + const path_type& + path () const {return p_;} + + const dir_path& + base () const {return b_;} + + dir_entry () = default; + dir_entry (entry_type t, path_type p, dir_path b) + : t_ (t), p_ (std::move (p)), b_ (std::move (b)) {} + + private: + entry_type + type (bool link) const; + + private: + friend class dir_iterator; + + mutable entry_type t_ = entry_type::unknown; // Lazy evaluation. + mutable entry_type lt_ = entry_type::unknown; // Lazy evaluation. + path_type p_; + dir_path b_; + }; + + class LIBBUTL_EXPORT dir_iterator + { + public: + typedef dir_entry value_type; + typedef const dir_entry* pointer; + typedef const dir_entry& reference; + typedef std::ptrdiff_t difference_type; + typedef std::input_iterator_tag iterator_category; + + ~dir_iterator (); + dir_iterator () = default; + + explicit + dir_iterator (const dir_path&); + + dir_iterator (const dir_iterator&) = delete; + dir_iterator& operator= (const dir_iterator&) = delete; + + dir_iterator (dir_iterator&& x); + dir_iterator& operator= (dir_iterator&&); + + dir_iterator& operator++ () {next (); return *this;} + + reference operator* () const {return e_;} + pointer operator-> () const {return &e_;} + + friend bool operator== (const dir_iterator&, const dir_iterator&); + friend bool operator!= (const dir_iterator&, const dir_iterator&); + + private: + void + next (); + + private: + dir_entry e_; + +#ifndef _WIN32 + DIR* h_ = nullptr; +#else + intptr_t h_ = -1; +#endif + }; + + // Range-based for loop support. + // + // for (const auto& de: dir_iterator (dir_path ("/tmp"))) ... + // + // Note that the "range" (which is the "begin" iterator), is no + // longer usable. In other words, don't do this: + // + // dir_iterator i (...); + // for (...: i) ... + // ++i; // Invalid. + // + inline dir_iterator begin (dir_iterator&); + inline dir_iterator end (const dir_iterator&); + + // Wildcard pattern match and search (aka glob). + // + + // Return true if name matches pattern. Both must be single path components, + // possibly with a trailing directory separator to indicate a directory. + // + // If the pattern ends with a directory separator, then it only matches a + // directory name (i.e., ends with a directory separator, but potentially + // different). Otherwise, it only matches a non-directory name (no trailing + // directory separator). + // + // Currently the following wildcard characters are supported: + // + // * - match any number of characters (including zero) + // ? - match any single character + // + LIBBUTL_EXPORT bool + path_match (const std::string& pattern, const std::string& name); + + // Search for paths matching the pattern calling the specified function for + // each matching path (see below for details). + // + // If the pattern is relative, then search in the start directory. If the + // start directory is empty, then search in the current working directory. + // Searching in non-existent directories is not an error. Throw + // std::system_error in case of a failure (insufficient permissions, etc). + // + // The pattern may contain multiple components that include wildcards. On + // Windows the drive letter may not be a wildcard. + // + // In addition to the wildcard characters listed in path_match(), + // path_search() also recognizes the ** and *** wildcard sequences. If a + // path component contains **, then it is matched just like * but in all the + // subdirectories, recursively. The *** wildcard behaves like ** but also + // matches the start directory itself. + // + // So, for example, foo/bar-**.txt will return all the files matching the + // bar-*.txt pattern in all the subdirectoris of foo/. And foo/f***/ will + // return all the subdirectories matching the f*/ pattern plus foo/ itself. + // + // Note that having multiple recursive components in the pattern we can end + // up with calling func() multiple times (once per such a component) for the + // same path. For example the search with pattern f***/b**/ starting in + // directory foo, that has the foo/fox/box/ structure, will result in + // calling func(foo/fox/box/) twice: first time for being a child of fox/, + // second time for being a child of foo/. + // + // The callback function is called for both intermediate matches (interm is + // true) and final matches (interm is false). Pattern is what matched the + // last component in the path and is empty if the last component is not a + // pattern (final match only; say as in */foo.txt). + // + // If the callback function returns false for an intermediate path, then no + // further search is performed at or below this path. If false is returned + // for a final match, then the entire search is stopped. + // + // The path can be moved for the final match or for an intermediate match + // but only if false is returned. + // + // As an example, consider pattern f*/bar/b*/*.txt and path + // foo/bar/baz/x.txt. The sequence of calls in this case will be: + // + // (foo/, f*/, true) + // (foo/bar/baz/, b*/, true) + // (foo/bar/baz/x.txt, *.txt, false) + // + // If the pattern contains a recursive wildcard, then the callback function + // can be called for the same directory twice: first time as an intermediate + // match with */ pattern to decide if to recursively traverse the directory, + // and the second time if the directory matches the pattern component (either + // as an intermediate or a final match). As an example, consider pattern + // b**/c* and directory tree a/b/c/. The sequence of calls in this case will + // be: + // + // (a/, */, true) + // (a/b/, */ true) + // (a/b/c/, */, true) + // (a/b/, b*/, true) + // (a/b/c/, c*/, false) + // + LIBBUTL_EXPORT void + path_search (const path& pattern, + const std::function<bool (path&&, + const std::string& pattern, + bool interm)>&, + const dir_path& start = dir_path (), + bool follow_symlinks = true); +} + +#include <libbutl/filesystem.ixx> + +#endif // LIBBUTL_FILESYSTEM_HXX |