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Diffstat (limited to 'src/fs-extension-functions.cc')
| -rw-r--r-- | src/fs-extension-functions.cc | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/src/fs-extension-functions.cc b/src/fs-extension-functions.cc new file mode 100644 index 0000000..a9d34fc --- /dev/null +++ b/src/fs-extension-functions.cc @@ -0,0 +1,260 @@ +/** + * Copyright (c) 2013, Timothy Stack + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * * Neither the name of Timothy Stack nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * @file fs-extension-functions.cc + */ + +#include <string> + +#include <errno.h> +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <sys/param.h> +#include <sys/stat.h> +#include <unistd.h> + +#include "config.h" +#include "sqlite-extension-func.hh" +#include "sqlite3.h" +#include "vtab_module.hh" + +using namespace mapbox; + +static util::variant<const char*, string_fragment> +sql_basename(const char* path_in) +{ + int text_end = -1; + + if (path_in[0] == '\0') { + return "."; + } + + for (ssize_t lpc = strlen(path_in) - 1; lpc >= 0; lpc--) { + if (path_in[lpc] == '/' || path_in[lpc] == '\\') { + if (text_end != -1) { + return string_fragment(path_in, lpc + 1, text_end); + } + } else if (text_end == -1) { + text_end = (int) (lpc + 1); + } + } + + if (text_end == -1) { + return "/"; + } else { + return string_fragment(path_in, 0, text_end); + } +} + +static util::variant<const char*, string_fragment> +sql_dirname(const char* path_in) +{ + ssize_t text_end; + + text_end = strlen(path_in) - 1; + while (text_end >= 0 + && (path_in[text_end] == '/' || path_in[text_end] == '\\')) + { + text_end -= 1; + } + + while (text_end >= 0) { + if (path_in[text_end] == '/' || path_in[text_end] == '\\') { + return string_fragment(path_in, 0, text_end == 0 ? 1 : text_end); + } + + text_end -= 1; + } + + return path_in[0] == '/' ? "/" : "."; +} + +static nonstd::optional<std::string> +sql_joinpath(const std::vector<const char*>& paths) +{ + std::string full_path; + + if (paths.empty()) { + return nonstd::nullopt; + } + + for (auto& path_in : paths) { + if (path_in == nullptr) { + return nonstd::nullopt; + } + + if (path_in[0] == '/' || path_in[0] == '\\') { + full_path.clear(); + } + if (!full_path.empty() && full_path[full_path.length() - 1] != '/' + && full_path[full_path.length() - 1] != '\\') + { + full_path += "/"; + } + full_path += path_in; + } + + return full_path; +} + +static std::string +sql_readlink(const char* path) +{ + struct stat st; + + if (lstat(path, &st) == -1) { + throw sqlite_func_error( + "unable to stat path: {} -- {}", path, strerror(errno)); + } + + char buf[st.st_size]; + ssize_t rc; + + rc = readlink(path, buf, sizeof(buf)); + if (rc < 0) { + if (errno == EINVAL) { + return path; + } + throw sqlite_func_error( + "unable to read link: {} -- {}", path, strerror(errno)); + } + + return std::string(buf, rc); +} + +static std::string +sql_realpath(const char* path) +{ + char resolved_path[PATH_MAX]; + + if (realpath(path, resolved_path) == nullptr) { + throw sqlite_func_error( + "Could not get real path for {} -- {}", path, strerror(errno)); + } + + return resolved_path; +} + +int +fs_extension_functions(struct FuncDef** basic_funcs, + struct FuncDefAgg** agg_funcs) +{ + static struct FuncDef fs_funcs[] = { + + sqlite_func_adapter<decltype(&sql_basename), sql_basename>::builder( + help_text("basename", "Extract the base portion of a pathname.") + .sql_function() + .with_parameter({"path", "The path"}) + .with_tags({"filename"}) + .with_example({"To get the base of a plain file name", + "SELECT basename('foobar')"}) + .with_example( + {"To get the base of a path", "SELECT basename('foo/bar')"}) + .with_example({"To get the base of a directory", + "SELECT basename('foo/bar/')"}) + .with_example({"To get the base of an empty string", + "SELECT basename('')"}) + .with_example({"To get the base of a Windows path", + "SELECT basename('foo\\bar')"}) + .with_example({"To get the base of the root directory", + "SELECT basename('/')"})), + + sqlite_func_adapter<decltype(&sql_dirname), sql_dirname>::builder( + help_text("dirname", "Extract the directory portion of a pathname.") + .sql_function() + .with_parameter({"path", "The path"}) + .with_tags({"filename"}) + .with_example({"To get the directory of a relative file path", + "SELECT dirname('foo/bar')"}) + .with_example({"To get the directory of an absolute file path", + "SELECT dirname('/foo/bar')"}) + .with_example( + {"To get the directory of a file in the root directory", + "SELECT dirname('/bar')"}) + .with_example({"To get the directory of a Windows path", + "SELECT dirname('foo\\bar')"}) + .with_example({"To get the directory of an empty path", + "SELECT dirname('')"})), + + sqlite_func_adapter<decltype(&sql_joinpath), sql_joinpath>::builder( + help_text("joinpath", "Join components of a path together.") + .sql_function() + .with_parameter( + help_text( + "path", + "One or more path components to join together. " + "If an argument starts with a forward or backward " + "slash, it will be considered " + "an absolute path and any preceding elements will " + "be ignored.") + .one_or_more()) + .with_tags({"filename"}) + .with_example( + {"To join a directory and file name into a relative path", + "SELECT joinpath('foo', 'bar')"}) + .with_example( + {"To join an empty component with other names into " + "a relative path", + "SELECT joinpath('', 'foo', 'bar')"}) + .with_example( + {"To create an absolute path with two path components", + "SELECT joinpath('/', 'foo', 'bar')"}) + .with_example( + {"To create an absolute path from a path component " + "that starts with a forward slash", + "SELECT joinpath('/', 'foo', '/bar')"})), + + sqlite_func_adapter<decltype(&sql_readlink), sql_readlink>::builder( + help_text("readlink", "Read the target of a symbolic link.") + .sql_function() + .with_parameter({"path", "The path to the symbolic link."}) + .with_tags({"filename"})), + + sqlite_func_adapter<decltype(&sql_realpath), sql_realpath>::builder( + help_text( + "realpath", + "Returns the resolved version of the given path, expanding " + "symbolic links and " + "resolving '.' and '..' references.") + .sql_function() + .with_parameter({"path", "The path to resolve."}) + .with_tags({"filename"})), + + /* + * TODO: add other functions like normpath, ... + */ + + {nullptr}, + }; + + *basic_funcs = fs_funcs; + *agg_funcs = nullptr; + + return SQLITE_OK; +} |