Remove `const` qualifier from the argument of `free()` and `realloc()`,

[helenos.git] / uspace / app / bdsh / compl.c

/*
 * Copyright (c) 2011 Jiri Svoboda
 * Copyright (c) 2011 Martin Sucha
 * 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <stdbool.h>
#include <dirent.h>
#include <errno.h>
#include <macros.h>
#include <stdlib.h>
#include <vfs/vfs.h>
#include <str.h>

#include "cmds/cmds.h"
#include "compl.h"
#include "exec.h"
#include "tok.h"

static errno_t compl_init(wchar_t *text, size_t pos, size_t *cstart, void **state);
static errno_t compl_get_next(void *state, char **compl);
static void compl_fini(void *state);

/** Bdsh implementation of completion ops. */
tinput_compl_ops_t compl_ops = {
        .init = compl_init,
        .get_next = compl_get_next,
        .fini = compl_fini
};

/** Completion state object.
 *
 * The state object contains 'iterators' for modules, builtins and
 * executables in directories.
 */
typedef struct {
        /** String prefix which we are trying to complete. */
        char *prefix;
        /** Length of string prefix (number of characters) */
        size_t prefix_len;

        /** Pointer inside list of modules */
        module_t *module;
        /** Pointer inside list of builtins */
        builtin_t *builtin;

        /** Pointer inside list of directories */
        const char *const *path;
        /** If not @c NULL, should be freed in the end. */
        char **path_list;
        /** Current open directory */
        DIR *dir;

        char *last_compl;

        /**
         * @c true if we are completing a command, @c false if we are
         * completing an argument
         */
        bool is_command;
} compl_t;

/** Init completion.
 *
 * Set up iterators in completion object, based on current token.
 */
static errno_t compl_init(wchar_t *text, size_t pos, size_t *cstart, void **state)
{
        compl_t *cs = NULL;
        char *stext = NULL;
        char *prefix = NULL;
        char *dirname = NULL;
        errno_t retval;
        
        token_t *tokens = calloc(WORD_MAX, sizeof(token_t));
        if (tokens == NULL) {
                retval = ENOMEM;
                goto error;
        }
        
        size_t pref_size;
        char *rpath_sep;
        static const char *dirlist_arg[] = { ".", NULL };
        tokenizer_t tok;
        ssize_t current_token;
        size_t tokens_length;
        
        cs = calloc(1, sizeof(compl_t));
        if (!cs) {
                retval = ENOMEM;
                goto error;
        }
        
        /* Convert text buffer to string */
        stext = wstr_to_astr(text);
        if (stext == NULL) {
                retval = ENOMEM;
                goto error;
        }
        
        /* Tokenize the input string */
        retval = tok_init(&tok, stext, tokens, WORD_MAX);
        if (retval != EOK) {
                goto error;
        }
        
        retval = tok_tokenize(&tok, &tokens_length);
        if (retval != EOK) {
                goto error;
        }
        
        /* Find the current token */
        for (current_token = 0; current_token < (ssize_t) tokens_length;
            current_token++) {
                token_t *t = &tokens[current_token];
                size_t end = t->char_start + t->char_length;
                
                /*
                 * Check if the caret lies inside the token or immediately
                 * after it
                 */
                if (t->char_start <= pos && pos <= end) {
                        break;
                }
        }
        
        if (tokens_length == 0)
                current_token = -1;
        
        if ((current_token >= 0) && (tokens[current_token].type != TOKTYPE_SPACE))
                *cstart = tokens[current_token].char_start;
        else
                *cstart = pos;
        
        /*
         * Extract the prefix being completed
         * XXX: handle strings, etc.
         */
        pref_size = str_lsize(stext, pos - *cstart);
        prefix = malloc(pref_size + 1);
        if (prefix == NULL) {
                retval = ENOMEM;
                goto error;
        }
        prefix[pref_size] = 0;

        if (current_token >= 0) {
                str_ncpy(prefix, pref_size + 1, stext +
                    tokens[current_token].byte_start, pref_size);
        }

        /*
         * Determine if the token being completed is a command or argument.
         * We look at the previous token. If there is none or it is a pipe
         * ('|'), it is a command, otherwise it is an argument.
         */

        /* Skip any whitespace before current token */
        ssize_t prev_token = current_token - 1;
        if ((prev_token >= 0) && (tokens[prev_token].type == TOKTYPE_SPACE))
                prev_token--;
        
        /*
         * It is a command if it is the first token or if it immediately
         * follows a pipe token.
         */
        if ((prev_token < 0) || (tokens[prev_token].type == TOKTYPE_SPACE))
                cs->is_command = true;
        else
                cs->is_command = false;

        rpath_sep = str_rchr(prefix, '/');
        if (rpath_sep != NULL) {
                /* Extract path. For path beginning with '/' keep the '/'. */
                dirname = str_ndup(prefix, max(1, rpath_sep - prefix));
                if (dirname == NULL) {
                        retval = ENOMEM;
                        goto error;
                }

                /* Extract name prefix */
                cs->prefix = str_dup(rpath_sep + 1);
                if (cs->prefix == NULL) {
                        retval = ENOMEM;
                        goto error;
                }
                *cstart += rpath_sep + 1 - prefix;
                free(prefix);
                prefix = NULL;

                cs->path_list = malloc(sizeof(char *) * 2);
                if (cs->path_list == NULL) {
                        retval = ENOMEM;
                        goto error;
                }
                cs->path_list[0] = dirname;
                cs->path_list[1] = NULL;
                /* The second const ensures that we can't assign a const
                 * string to the non-const array. */
                cs->path = (const char *const *) cs->path_list;

        } else if (cs->is_command) {
                /* Command without path */
                cs->module = modules;
                cs->builtin = builtins;
                cs->prefix = prefix;
                cs->path = &search_dir[0];
        } else {
                /* Argument without path */
                cs->prefix = prefix;
                cs->path = &dirlist_arg[0];
        }

        cs->prefix_len = str_length(cs->prefix);
        
        tok_fini(&tok);

        *state = cs;
        return EOK;

error:
        /* Error cleanup */
        
        tok_fini(&tok);

        if (cs != NULL && cs->path_list != NULL) {
                size_t i = 0;
                while (cs->path_list[i] != NULL) {
                        free(cs->path_list[i]);
                        ++i;
                }
                free(cs->path_list);
        }

        if ((cs != NULL) && (cs->prefix != NULL))
                free(cs->prefix);
        
        if (dirname != NULL)
                free(dirname);
        
        if (prefix != NULL)
                free(prefix);
        
        if (stext != NULL)
                free(stext);
        
        if (cs != NULL)
                free(cs);
        
        if (tokens != NULL)
                free(tokens);

        return retval;
}

/** Determine if completion matches the required prefix.
 *
 * Required prefix is stored in @a cs->prefix.
 *
 * @param cs    Completion state object
 * @param compl Completion string
 * @return      @c true when @a compl matches, @c false otherwise
 */
static bool compl_match_prefix(compl_t *cs, const char *compl)
{
        return str_lcmp(compl, cs->prefix, cs->prefix_len) == 0;
}

/** Get next match. */
static errno_t compl_get_next(void *state, char **compl)
{
        compl_t *cs = (compl_t *) state;
        struct dirent *dent;

        *compl = NULL;

        if (cs->last_compl != NULL) {
                free(cs->last_compl);
                cs->last_compl = NULL;
        }

        /* Modules */
        if (cs->module != NULL) {
                while (*compl == NULL && cs->module->name != NULL) {
                        if (compl_match_prefix(cs, cs->module->name)) {
                                asprintf(compl, "%s ", cs->module->name);
                                cs->last_compl = *compl;
                                if (*compl == NULL)
                                        return ENOMEM;
                        }
                        cs->module++;
                }
        }

        /* Builtins */
        if (cs->builtin != NULL) {
                while (*compl == NULL && cs->builtin->name != NULL) {
                        if (compl_match_prefix(cs, cs->builtin->name)) {
                                asprintf(compl, "%s ", cs->builtin->name);
                                cs->last_compl = *compl;
                                if (*compl == NULL)
                                        return ENOMEM;
                        }
                        cs->builtin++;
                }
        }

        /* Files and directories. We scan entries from a set of directories. */
        if (cs->path != NULL) {
                while (*compl == NULL) {
                        /* Open next directory */
                        while (cs->dir == NULL) {
                                if (*cs->path == NULL)
                                        break;

                                cs->dir = opendir(*cs->path);

                                /* Skip directories that we fail to open. */
                                if (cs->dir == NULL)
                                        cs->path++;
                        }

                        /* If it was the last one, we are done */
                        if (cs->dir == NULL)
                                break;

                        /* Read next directory entry */
                        dent = readdir(cs->dir);
                        if (dent == NULL) {
                                /* Error. Close directory, go to next one */
                                closedir(cs->dir);
                                cs->dir = NULL;
                                cs->path++;
                                continue;
                        }

                        if (compl_match_prefix(cs, dent->d_name)) {
                                /* Construct pathname */
                                char *ent_path;
                                asprintf(&ent_path, "%s/%s", *cs->path, dent->d_name);
                                vfs_stat_t ent_stat;
                                if (vfs_stat_path(ent_path, &ent_stat) != EOK) {
                                        /* Error */
                                        free(ent_path);
                                        continue;
                                }

                                free(ent_path);

                                /* If completing command, do not match directories. */
                                if (!ent_stat.is_directory || !cs->is_command) {
                                        asprintf(compl, "%s%c", dent->d_name,
                                            ent_stat.is_directory ? '/' : ' ');
                                        cs->last_compl = *compl;
                                        if (*compl == NULL)
                                                return ENOMEM;
                                }
                        }
                }
        }

        if (*compl == NULL)
                return ENOENT;

        return EOK;
}

/** Finish completion operation. */
static void compl_fini(void *state)
{
        compl_t *cs = (compl_t *) state;

        if (cs->path_list != NULL) {
                size_t i = 0;
                while (cs->path_list[i] != NULL) {
                        free(cs->path_list[i]);
                        ++i;
                }
                free(cs->path_list);
        }

        if (cs->last_compl != NULL)
                free(cs->last_compl);
        if (cs->dir != NULL)
                closedir(cs->dir);

        free(cs->prefix);
        free(cs);
}