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+/**
+ * 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;
+}