lnav/src/fs-extension-functions.cc

/**
 * 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 "config.h"

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <stdint.h>

#include <string>
#include <stddef.h>

#include "sqlite3.h"

#include "sqlite-extension-func.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 - lpc);
            }
        }
        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 void sql_joinpath(sqlite3_context *context,
                         int argc, sqlite3_value **argv)
{
    std::string full_path;
    int         lpc;

    if (argc == 0) {
        sqlite3_result_null(context);
        return;
    }

    for (lpc = 0; lpc < argc; lpc++) {
        if (sqlite3_value_type(argv[lpc]) == SQLITE_NULL) {
            sqlite3_result_null(context);
            return;
        }
    }

    for (lpc = 0; lpc < argc; lpc++) {
        const char *path_in;

        path_in = (const char *)sqlite3_value_text(argv[lpc]);

        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;
    }

    sqlite3_result_text(context, full_path.c_str(), -1, SQLITE_TRANSIENT);
}

int fs_extension_functions(const struct FuncDef **basic_funcs,
                           const struct FuncDefAgg **agg_funcs)
{
    static const struct FuncDef fs_funcs[] = {

        sqlite_func_adapter<decltype(&sql_basename), sql_basename>::builder(
            "basename",
            "Extract the base portion of a pathname",
            {
                {"path", "The path"},
            }),

        sqlite_func_adapter<decltype(&sql_dirname), sql_dirname>::builder(
            "dirname",
            "Extract the directory portion of a pathname",
            {
                {"path", "The path"},
            }),

        { "joinpath", -1, 0, SQLITE_UTF8, 0, sql_joinpath },

        /*
         * TODO: add other functions like readlink, normpath, ... 
         */

        { NULL }
    };

    *basic_funcs = fs_funcs;
    *agg_funcs   = NULL;

    return SQLITE_OK;
}