src/server/config/serverconfig.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2020 Olaf Wintermann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
 */


#include "serverconfig.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include <ucx/buffer.h>
#include <ucx/utils.h>

ServerConfig* serverconfig_load(const char *file) {
    FILE *in = fopen(file, "r");
    if(in == NULL) {
        return NULL;
    }
    
    UcxBuffer *buf = ucx_buffer_new(NULL, 4096, UCX_BUFFER_AUTOEXTEND);
    if(!buf) {
        fclose(in);
        return NULL;
    }
    
    ucx_stream_copy(in, buf, (read_func)fread, (write_func)ucx_buffer_write);
    fclose(in);
    
    ServerConfig *scfg = serverconfig_parse(scstrn(buf->space, buf->size));
    
    ucx_buffer_free(buf);
    return scfg;
}


static CFGToken get_next_token(scstr_t content, int *pos) {
    CFGToken token = { {NULL, 0}, CFG_NO_TOKEN };
    CFGTokenType type = CFG_TOKEN;
    
    int start = *pos;
    
    int token_begin = -1;
    int token_end = content.length-1;
    
    int quote = 0;
    int comment = 0;
    
    int i;
    char prev = 0;
    for(i=start;i<content.length;i++) {
        char c = content.ptr[i];
        if(c == '\n') {
            if(quote) {
                *pos = i;
                return token; // error
            } else if(start == i) {
                // single newline char token
                type = CFG_TOKEN_NEWLINE;
                token_begin = i;
                token_end = i+1;
                break;
            }
            
            token_end = i;
            if(token_begin < 0) {
                // only space/comment token
                token_begin = start;
                type = comment ? CFG_TOKEN_COMMENT : CFG_TOKEN_SPACE;
            }
            // make sure next run will return current newline char as token
            i--;
            break;
        } else if(quote) {
            if(c == '"' && prev != '\\') {
                quote = 0;
            }
        } else if(comment) {
            // ignore
            if(c == '\n') {
                comment = 0;
            }
        } else if(c == '#') {
            comment = 1;
        } else if(isspace(c)) {
            if(token_begin >= 0) {
                token_end = i;
                break;
            }
        } else if(c == '"') {
            quote = 1;
            if(token_begin < 0) {
                token_begin = i;
            }
        } else if(token_begin < 0) {
            token_begin = i;
        }
        prev = c;
    }
    
    *pos = i + 1;
    
    if(token_begin < 0) {
        return token; // error
    }
    
    token.type = type;
    token.content = scstrsubsl(content, token_begin, token_end - token_begin);
    return token;
}


static void test_print_config(ConfigNode *parent) {
    UCX_FOREACH(elm, parent->children) {
        ConfigNode *node = elm->data;
        
        if(node->type == CONFIG_NODE_SPACE) {
            printf("sp: %s", node->text_begin.ptr);
        } else if(node->type == CONFIG_NODE_COMMENT) {
            printf("cm: %s", node->text_begin.ptr);
        } else if(node->type == CONFIG_NODE_OBJECT) {
            printf("o{: %s : %s", node->name.ptr, node->text_begin.ptr);
            test_print_config(node);
            printf("o}: %s", node->text_end.ptr);
        } else if(node->type == CONFIG_NODE_DIRECTIVE) {
            printf("di: %s", node->text_begin.ptr);
        } else {
            printf("fk: %s", node->text_begin.ptr);
        }
    }
}

ServerConfig* serverconfig_parse(scstr_t content) {
    UcxMempool *mp = ucx_mempool_new(512);
    if(!mp) return NULL;
    UcxAllocator *a = mp->allocator;
    
    ServerConfig *config = ucx_mempool_malloc(mp, sizeof(ServerConfig));
    if(!config) {
        ucx_mempool_destroy(mp);
        return NULL;
    }
    config->mp = mp;
    
    // PARSE:
    // first non space/comment token is directive/object name
    // following tokens are arguments
    // newline starts new directive
    // '{' converts directive to object and following directives will
    // be placed into the object
    int pos = 0; // needed for tokenizer
    CFGToken token;
    
    ConfigNode *root_obj = ucx_mempool_calloc(mp, 1, sizeof(ConfigNode));
    root_obj->type = CONFIG_NODE_OBJECT;
    
    UcxList *node_stack = ucx_list_prepend(NULL, root_obj);
    
    ConfigNode *current = ucx_mempool_calloc(mp, 1, sizeof(ConfigNode));
    current->type = CONFIG_NODE_SPACE;
    ConfigNode *obj = NULL;
    int obj_closed = 0;
    
    int text_start = 0;
    int err = 0;
    while((token = get_next_token(content, &pos)).type != CFG_NO_TOKEN) {
        //printf("%s [%.*s]\n", token_type_str(token.type), (int)token.content.length, token.content.ptr);
        
        switch(token.type) {
            CFG_NO_TOKEN: break;
            case CFG_TOKEN_COMMENT: {
                if(current->type == CONFIG_NODE_SPACE) {
                    current->type = CONFIG_NODE_COMMENT;
                }
                break;
            }
            case CFG_TOKEN_SPACE: break;
            case CFG_TOKEN_NEWLINE: {
                scstr_t line = scstrsubsl(content, text_start, pos - text_start);
                text_start = pos;
                
                sstr_t line_cp = sstrdup_a(a, line);

                ConfigNode *parent = node_stack->data;
                if(current->type == CONFIG_NODE_CLOSE_OBJECT) {
                    parent->text_end = line_cp;
                    node_stack = ucx_list_remove_a(a, node_stack, node_stack);
                } else if(current->type == CONFIG_NODE_OPEN_OBJECT) {
                    sstr_t new_textbegin = sstrcat_a(a, 2, obj->text_begin, line_cp);
                    alfree(a, obj->text_begin.ptr);
                    alfree(a, line_cp.ptr);
                    obj->text_begin = new_textbegin;
                } else {
                    current->text_begin = line_cp;
                    ConfigNode *parent = node_stack->data;
                    parent->children = ucx_list_append_a(a, parent->children, current);
                }
                
                if(obj && obj->type == CONFIG_NODE_OBJECT) {
                    node_stack = ucx_list_prepend_a(a, node_stack, obj);
                    obj = NULL;
                }

                current = ucx_mempool_calloc(mp, 1, sizeof(ConfigNode));
                current->type = CONFIG_NODE_SPACE;
                
                obj_closed = 0;
                break;
            }
            case CFG_TOKEN: {
                if(!sstrcmp(token.content, S("{"))) {
                    if(!obj) {
                        err = 1;
                        break;
                    }
                    obj->type = CONFIG_NODE_OBJECT;
                    if(current != obj) {
                        current->type = CONFIG_NODE_OPEN_OBJECT;
                    }
                } else if(!sstrcmp(token.content, S("}"))) {
                    obj_closed = 1; // force newline before next directive
                    obj = NULL;
                    current->type = CONFIG_NODE_CLOSE_OBJECT;
                } else {
                    if(obj_closed) {
                        err = 1;
                        break;
                    }
                    
                    if(!current->name.ptr) {
                        current->name = sstrdup_a(a, token.content);
                        current->type = CONFIG_NODE_DIRECTIVE;
                        obj = current;
                    } else {
                        ConfigArg *arg = ucx_mempool_calloc(mp, 1, sizeof(ConfigArg));
                        // TODO: add support for key/value
                        arg->value = sstrdup_a(a, token.content);
                        current->args = ucx_list_append_a(a, current->args, arg);
                    }
                }
                break;
            }
        }
        
        if(err) {
            break;
        }
    }
    
    if(pos < content.length || err) {
        // content not fully parsed because of an error
        ucx_mempool_destroy(mp);
        return NULL;
    }
    
    //test_print_config(&root_obj);
    config->root = root_obj;
    config->tab = sstrdup_a(a, SC("\t"));
    
    return config;
}

void serverconfig_free(ServerConfig *cfg) {
    ucx_mempool_destroy(cfg->mp);
}

ConfigNode* serverconfig_get_node(ConfigNode *parent, ConfigNodeType type, scstr_t name) {
    UCX_FOREACH(elm, parent->children) {
        ConfigNode *node = elm->data;
        if(node->type == type && !sstrcmp(node->name, name)) {
            return node;
        }
    }
    return NULL;
}

UcxList* serverconfig_get_node_list(ConfigNode *parent, ConfigNodeType type, scstr_t name) {
    UcxList *nodes = NULL;
    
    UCX_FOREACH(elm, parent->children) {
        ConfigNode *node = elm->data;
        if(node->type == type && !sstrcmp(node->name, name)) {
            nodes = ucx_list_append(nodes, node);
        }
    }
    
    return nodes;
}

scstr_t serverconfig_directive_value(ConfigNode *obj, scstr_t name) {
    ConfigNode *node = serverconfig_get_node(obj, CONFIG_NODE_DIRECTIVE, name);
    if(node && ucx_list_size(node->args) == 1) {
        ConfigArg *arg = node->args->data;
        return SCSTR(arg->value);
    }
    return scstrn(NULL, 0);
}