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 "conf.h"

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

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

ServerConfig* serverconfig_load(const char *file) {
    CxMempool *mp = cxBasicMempoolCreate(512);
    if(!mp) {
        return NULL;
    }
    
    ConfigParser2 parser;
    memset(&parser, 0, sizeof(ConfigParser2));
    parser.mp = mp;
    parser.allow_hierarchy = true;
    ConfigNode *root = serverconfig_load_file(&parser, file);
    if(!root) {
        cxMempoolDestroy(mp);
        return NULL;
    }
    
    ServerConfig *scfg = cxMalloc(mp->allocator, sizeof(ServerConfig));
    if(!scfg) {
        cxMempoolDestroy(mp);
        return NULL;
    }
    scfg->root = root;
    scfg->mp = mp;
    scfg->tab = cx_str("\t");
    
    return scfg;
}

ConfigNode* serverconfig_load_file(ConfigParser2 *parser, const char *file) {
    FILE *in = fopen(file, "r");
    if(in == NULL) {
        parser->error = CONFIG_PARSER_IO_ERROR;
        parser->io_errno = errno;
        return NULL;
    }
    
    // temporary buffer to store the file content
    CxBuffer buf;
    if(cxBufferInit(&buf, NULL, 16384, cxDefaultAllocator, CX_BUFFER_AUTO_EXTEND|CX_BUFFER_FREE_CONTENTS)) {
        fclose(in);
        parser->error = CONFIG_PARSER_OOM;
        return NULL;
    }
    
    //ucx_stream_copy(in, buf, (read_func)fread, (write_func)ucx_buffer_write);
    char readbuf[2048];
    size_t r;
    while((r = fread(readbuf, 1, 2048, in)) > 0) {
        cxBufferWrite(readbuf, 1, r, &buf);
    }
    fclose(in);
    
    ConfigNode *root = serverconfig_parse(parser, cx_strn(buf.space, buf.size));
    cxBufferDestroy(&buf);
    return root;
}

static int scfg_char_is_delim(char c) {
    static const char *scfg_tokenizer_delim = "()/*%";
    for(int i=0;i<sizeof(scfg_tokenizer_delim)-1;i++) {
        if(c == scfg_tokenizer_delim[i]) {
            return 1;
        }
    }
    return 0;
}

static CFGToken get_next_token(cxstring 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(scfg_char_is_delim(c)) {
            if(token_begin >= 0) {
                token_end = i;
                i--;
                break;
            } else {
                token_begin = i;
                token_end = i+1;
                break;
            }
        } 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 = cx_strsubsl(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);
        }
    }
}
*/

static void config_arg_set_value(CxAllocator *a, ConfigParam *arg, CFGToken token) {
    cxstring nv = cx_strchr(token.content, '=');
    if(!nv.ptr) {
        arg->value = cx_strdup_a(a, token.content);
    } else {
        intptr_t eq = (intptr_t)(nv.ptr - token.content.ptr);
        cxstring name = token.content;
        name.length = (size_t)eq;
        
        cxstring value = nv;
        value.ptr++;
        value.length--;
        if(value.length > 1 && value.ptr[0] == '"' && value.ptr[value.length-1] == '"') {
            value.ptr++;
            value.length -= 2; // remove quote
        }
        
        arg->name = cx_strdup_a(a, name);
        arg->value = cx_strdup_a(a, value);
    }
}

static int nodestack_prepend(CxAllocator *a, ConfigNodeStack **stack, ConfigNode *node) {
    ConfigNodeStack *elm = cxMalloc(a, sizeof(ConfigNodeStack));
    if(!elm) return 1;
    elm->node = node;
    elm->next = NULL;
    cx_linked_list_prepend((void**)stack, NULL, -1, offsetof(ConfigNodeStack, next), elm);
    return 0;
}

ConfigNode* serverconfig_parse(ConfigParser2 *parser, cxstring content) {
    CxMempool *mp = parser->mp;
    CxAllocator *a = (CxAllocator*)mp->allocator;
    
    // 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 = cxCalloc(a, 1, sizeof(ConfigNode));
    root_obj->type = CONFIG_NODE_OBJECT;
    
    ConfigNodeStack *node_stack = cxMalloc(a, sizeof(ConfigNodeStack));
    node_stack->node = root_obj;
    node_stack->next = NULL;
    
    ConfigNode *current = cxCalloc(a, 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) {
            case 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: {
                cxstring line = cx_strsubsl(content, text_start, pos - text_start);
                text_start = pos;
                
                cxmutstr line_cp = cx_strdup_a(a, line);

                ConfigNode *parent = node_stack->node;
                if(current->type == CONFIG_NODE_CLOSE_OBJECT) {
                    // this is a newline after a object is closed with '}'
                    // the line containing "}\n" should be added to the object
                    parent->text_end = line_cp;
                    // validate
                    if(parser->validateObjEnd && parser->validateObjEnd(parser, parent)) {
                        // validation failed
                        err = 1;
                        break;
                    }
                    // done with this object, remove it from the stack
                    ConfigNodeStack *remove_item = node_stack;
                    node_stack = node_stack->next;
                    cxFree(a, remove_item);
                } else if(current->type == CONFIG_NODE_OPEN_OBJECT) {
                    // newline after a object is opened with '{'
                    // append '{' to the object text
                    cxmutstr new_textbegin = cx_strcat_a(a, 2, obj->text_begin, line_cp);
                    cxFree(a, obj->text_begin.ptr);
                    cxFree(a, line_cp.ptr);
                    obj->text_begin = new_textbegin;
                } else {
                    // normal line containing a directive, space or comment
                    
                    // add it to parent node
                    current->text_begin = line_cp;
                    CFG_NODE_ADD(&parent->children_begin, &parent->children_end, current);
                    
                    // validate after CFG_NODE_ADD, because now current->prev is set
                    if(current->type == CONFIG_NODE_DIRECTIVE &&
                       parser->validateDirective &&
                       parser->validateDirective(parser, current))
                    {
                        err = 1;
                        break;
                    }
                }
                
                // obj points to the previous node that started as a directive
                // the type is set to CONFIG_NODE_OBECT if it was followed by
                // a '{' character
                if(obj && obj->type == CONFIG_NODE_OBJECT) {
                    // new object started
                    if(parser->validateObjBegin && parser->validateObjBegin(parser, obj)) {
                        // validation callback failed
                        err = 1;
                        break;
                    }
                    
                    // add it to the stack
                    nodestack_prepend(a, &node_stack, obj);
                    obj = NULL;
                }

                current = cxCalloc(a, 1, sizeof(ConfigNode));
                current->type = CONFIG_NODE_SPACE;
                
                obj_closed = 0;
                break;
            }
            case CFG_TOKEN: {
                // normal text token
                // either a directive/obj name, parameter or { }
                
                if(!cx_strcmp(token.content, cx_str("{"))) {
                    // check if the parser allows an object hierarchy
                    if(!parser->allow_hierarchy) {
                        parser->error = CONFIG_PARSER_SYNTAX_ERROR;
                        err = 1;
                        break;
                    }
                    
                    // obj is pointing to the previous node that started
                    // a directive
                    if(!obj) {
                        err = 1;
                        break;
                    }
                    obj->type = CONFIG_NODE_OBJECT;
                    if(current != obj) {
                        current->type = CONFIG_NODE_OPEN_OBJECT;
                    }
                } else if(!cx_strcmp(token.content, cx_str("}"))) {
                    // check if the parser allows an object hierarchy
                    if(!parser->allow_hierarchy) {
                        parser->error = CONFIG_PARSER_SYNTAX_ERROR;
                        err = 1;
                        break;
                    }
                    
                    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) {
                        // currently this could be a directive or object
                        current->name = cx_strdup_a(a, token.content);
                        current->type = CONFIG_NODE_DIRECTIVE;
                        obj = current; // potential object
                    } else {
                        // name already set, therefore this token must
                        // be a parameter
                        ConfigParam *arg = cxCalloc(a, 1, sizeof(ConfigParam));
                        config_arg_set_value(a, arg, token);
                        CFG_PARAM_ADD(&current->args, NULL, arg);
                    }
                }
                break;
            }
        }
        
        if(err) {
            break;
        }
    }
    
    if(pos < content.length || err) {
        // content not fully parsed because of an error
        cxMempoolDestroy(mp);
        return NULL;
    }
    
    //test_print_config(&root_obj);
    return root_obj;
}

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

ConfigNode* serverconfig_get_node(ConfigNode *parent, ConfigNodeType type, cxstring name) {
    for(ConfigNode *node=parent->children_begin;node;node=node->next) {
        if(node->type == type && !cx_strcasecmp(cx_strcast(node->name), name)) {
            return node;
        }
    }
    return NULL;
}

CxList* serverconfig_get_node_list(ConfigNode *parent, ConfigNodeType type, cxstring name) {
    CxList *nodes = cxPointerLinkedListCreate(cxDefaultAllocator, cx_cmp_ptr);
    
    for(ConfigNode *node=parent->children_begin;node;node=node->next) {
        if(node->type == type && !cx_strcasecmp(cx_strcast(node->name), name)) {
            cxListAdd(nodes, node);
        }
    }
    
    return nodes;
}

cxstring serverconfig_object_directive_value(ConfigNode *obj, cxstring name) {
    ConfigNode *node = serverconfig_get_node(obj, CONFIG_NODE_DIRECTIVE, name);
    if(node && CFG_NUM_PARAMS(node->args) == 1) {
        ConfigParam *arg = node->args;
        return (cxstring){ arg->value.ptr, arg->value.length };
    }
    return (cxstring){ NULL, 0 };
}

cxstring serverconfig_directive_get_arg(ConfigNode *directive, cxstring arg_name) {
    cxstring ret = (cxstring){ NULL, 0 };
    ConfigParam *arg = directive->args;
    while(arg) {
        if(!cx_strcmp(arg_name, cx_strcast(arg->name))) {
            ret = cx_strcast(arg->value);
            break;
        }
        arg = arg->next;
    }
    
    return ret;
}


/* -------------------------- utility functions -------------------------- */

int serverconfig_validate_directive_name(
        ConfigNode *directive,
        const char *names[],
        size_t numnames,
        size_t *nameindex)
{
    for(size_t i=0;i<numnames;i++) {
        if(!cx_strcmp(cx_strcast(directive->name), cx_str(names[i]))) {
            *nameindex = i;
            return 0;
        }
    }
    return 1;
}

int serverconfig_check_param_names(ConfigNode *directive, ConfigParam **err) {
    ConfigParam *arg = directive->args;
    while(arg) {
        if(arg->name.length == 0) {
            *err = arg;
            return 1;
        }
        arg = arg->next;
    }
    return 0;
}

ConfigNode* serverconfig_previous_dir_or_obj(ConfigNode *node) {
    node = node->prev;
    while(node) {
        if(node->type == CONFIG_NODE_DIRECTIVE || node->type == CONFIG_NODE_OBJECT) {
            return node;
        }
        node = node->prev;
    }
    return NULL;
}

size_t serverconfig_children_count(ConfigNode *node, ConfigNodeType type) {
    size_t count = 0;
    node = node->children_begin;
    while(node) {
        if(node->type == type) {
            count++;
        }
        node = node->next;
    }
    return count;
}