/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 2018 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.
*/
#ifndef DAVQLPARSER_H
#define DAVQLPARSER_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>
#include <cx/string.h>
#include <cx/list.h>
/**
* Enumeration of possible statement types.
*/
typedef enum {DAVQL_ERROR, DAVQL_SELECT, DAVQL_SET} davqltype_t;
/**
* Enumeration of possible token classes.
*/
typedef enum {
DAVQL_TOKEN_INVALID, DAVQL_TOKEN_KEYWORD,
DAVQL_TOKEN_IDENTIFIER, DAVQL_TOKEN_FMTSPEC,
DAVQL_TOKEN_STRING, DAVQL_TOKEN_NUMBER, DAVQL_TOKEN_TIMESTAMP,
DAVQL_TOKEN_COMMA, DAVQL_TOKEN_OPENP, DAVQL_TOKEN_CLOSEP,
DAVQL_TOKEN_OPERATOR, DAVQL_TOKEN_END
} davqltokenclass_t;
/**
* Enumeration of possible expression types.
*/
typedef enum {
DAVQL_UNDEFINED_TYPE,
DAVQL_NUMBER, DAVQL_STRING, DAVQL_TIMESTAMP, DAVQL_IDENTIFIER,
DAVQL_UNARY, DAVQL_BINARY, DAVQL_LOGICAL, DAVQL_FUNCCALL
} davqlexprtype_t;
/**
* Enumeration of possible expression operators.
*/
typedef enum {
DAVQL_NOOP, DAVQL_CALL, DAVQL_ARGLIST, // internal representations
DAVQL_ADD, DAVQL_SUB, DAVQL_MUL, DAVQL_DIV,
DAVQL_AND, DAVQL_OR, DAVQL_XOR, DAVQL_NEG, // airthmetic
DAVQL_NOT, DAVQL_LAND, DAVQL_LOR, DAVQL_LXOR, // logical
DAVQL_EQ, DAVQL_NEQ, DAVQL_LT, DAVQL_GT, DAVQL_LE, DAVQL_GE,
DAVQL_LIKE, DAVQL_UNLIKE // comparisons
} davqloperator_t;
typedef struct DavQLToken DavQLToken;
struct DavQLToken {
davqltokenclass_t tokenclass;
cxstring value;
DavQLToken *prev;
DavQLToken *next;
};
/**
* An expression within a DAVQL query.
*/
typedef struct _davqlexpr DavQLExpression;
/**
* The structure for type DavQLExpression.
*/
struct _davqlexpr {
/**
* The original expression text.
* Contains the literal value, if type is LITERAL.
*/
cxstring srctext;
/**
* The expression type.
*/
davqlexprtype_t type;
/**
* Operator.
*/
davqloperator_t op;
/**
* Left or single operand.
* <code>NULL</code> for literals or identifiers.
*/
DavQLExpression *left;
/**
* Right operand.
* <code>NULL</code> for literals, identifiers or unary expressions.
*/
DavQLExpression *right;
};
/**
* A tuple representing an order criterion.
*/
typedef struct {
/**
* The column.
*/
DavQLExpression *column;
/**
* True, if the result shall be sorted descending, false otherwise.
* Default is false (ascending).
*/
_Bool descending;
} DavQLOrderCriterion;
/**
* A tuple representing a field.
*/
typedef struct {
/**
* The field name.
* <ul>
* <li>SELECT: the identifier or an alias name</li>
* <li>SET: the identifier</li>
* </ul>
*/
cxstring name;
/**
* The field expression.
* <ul>
* <li>SELECT: the queried property (identifier) or an expression</li>
* <li>SET: the expression for the value to be set</li>
* </ul>
*/
DavQLExpression *expr;
} DavQLField;
/**
* Query statement object.
* Contains the binary information about the parsed query.
*
* The grammar for a DavQLStatement is:
*
* <pre>
* Keyword = "select" | "set" | "from" | "at" | "as"
* | "where" | "anywhere" | "like" | "unlike"
* | "and" | "or" | "not" | "xor" | "with" | "infinity"
* | "order" | "by" | "asc" | "desc";
*
* Expression = AddExpression;
* AddExpression = MultExpression, [AddOperator, AddExpression];
* MultExpression = BitwiseExpression, [MultOperator, MultExpression];
* BitwiseExpression = UnaryExpression, [BitwiseOperator, BitwiseExpression];
* UnaryExpression = [UnaryOperator], (ParExpression | AtomicExpression);
* AtomicExpression = FunctionCall | Identifier | Literal;
* ParExpression = "(", Expression, ")";
*
* BitwiseOperator = "&" | "|" | "^";
* MultOperator = "*" | "/";
* AddOperator = "+" | "-";
* UnaryOperator = "+" | "-" | "~";
*
* FunctionCall = Identifier, "(", [ArgumentList], ")";
* ArgumentList = Expression, {",", Expression};
* Identifier = IdentifierChar - ?Digit?, {IdentifierChar}
* | "`", ?Character? - "`", {?Character? - "`"}, "`";
* IdentifierChar = ?Character? - (" "|",");
* Literal = Number | String | Timestamp;
* Number = ?Digit?, {?Digit?} | "%d";
* String = "'", {?Character? - "'" | "'''"} , "'" | "%s";
* Timestamp = "%t"; // TODO: maybe introduce a real literal
*
* LogicalExpression = BooleanExpression, [LogicalOperator, LogicalExpression];
* BooleanExpression = "not ", BooleanExpression
* | "(", LogicalExpression, ")"
* | BooleanPrimary;
* BooleanPrimary = Expression, (" like " | " unlike "), String
* | Expression, Comparison, Expression
* | FunctionCall | Identifier;
*
* LogicalOperator = " and " | " or " | " xor ";
* Comparison = | "=" | "<" | ">" | "<=" | ">=" | "!=";
*
* FieldExpressions = "-"
* | "*", {",", NamedField}
* | FieldExpression, {",", FieldExpression};
* FieldExpression = NamedField | Identifier;
* NamedField = Expression, " as ", Identifier;
*
* Assignments = Assignment, {",", Assignment};
* Assignment = Identifier, "=", Expression;
*
* Path = String
* | "/", [PathNode, {"/", PathNode}], ["/"];
* PathNode = {{?Character? - "/"} - Keyword};
*
* WithClause = "depth", "=", (Number | "infinity");
*
* OrderByClause = OrderByCriterion, {",", OrderByCriterion};
* OrderByCriterion = (Identifier | Number), [" asc"|" desc"];
*
* </pre>
*
* Note: mandatory spaces are part of the grammar. But you may also insert an
* arbitrary amount of optional spaces between two symbols if they are not part
* of an literal, identifier or the path.
*
* <b>SELECT:</b>
* <pre>
* SelectStatement = "select ", FieldExpressions,
* " from ", Path,
* [" with ", WithClause],
* [(" where ", LogicalExpression) | " anywhere"],
* [" order by ", OrderByClause];
* </pre>
*
* <b>SET:</b>
* <pre>
* SetStatement = "set ",Assignments,
* " at ", Path,
* [" with ", WithClause],
* (" where ", LogicalExpression) | " anywhere";
* </pre>
*
*/
typedef struct {
/**
* The original query text.
*/
cxstring srctext;
/**
* The statement type.
*/
davqltype_t type;
/**
* Error code, if any error occurred. Zero otherwise.
*/
int errorcode;
/**
* Error message, if any error occurred.
*/
char* errormessage;
/**
* The list of DavQLFields.
*/
CxList* fields;
/**
* A string that denotes the queried path.
*/
cxstring path;
/**
* Logical expression for selection.
* <code>NULL</code>, if there is no where clause.
*/
DavQLExpression* where;
/**
* The list of DavQLOrderCriterions.
* This is <code>NULL</code> for SET queries and may be <code>NULL</code>
* if the result doesn't need to be sorted.
*/
CxList* orderby;
/**
* The recursion depth for the statement.
* Defaults to 1.
* Magic numbers are DAV_DEPTH_INFINITY for infinity and
* DAV_DEPTH_PLACEHOLDER for a placeholder.
*/
int depth;
/**
* A list of all required arguments
*/
CxList* args;
} DavQLStatement;
/** Infinity recursion depth for a DavQLStatement. */
#define DAV_DEPTH_INFINITY -1
/** Depth needs to be specified at runtime. */
#define DAV_DEPTH_PLACEHOLDER -2
/** Unexpected token. */
#define DAVQL_ERROR_UNEXPECTED_TOKEN 1
/** A token has been found, for which no token class is applicable. */
#define DAVQL_ERROR_INVALID_TOKEN 2
/** A token that has been expected was not found. */
#define DAVQL_ERROR_MISSING_TOKEN 11
/** An expression has been expected, but was not found. */
#define DAVQL_ERROR_MISSING_EXPR 12
/** A closed parenthesis ')' is missing. */
#define DAVQL_ERROR_MISSING_PAR 13
/** An assignment operator '=' is missing. */
#define DAVQL_ERROR_MISSING_ASSIGN 14
/** The type of the expression could not be determined. */
#define DAVQL_ERROR_INVALID_EXPR 21
/** An operator has been found for an unary expression, but it is invalid. */
#define DAVQL_ERROR_INVALID_UNARY_OP 22
/** An operator has been found for a logical expression, but it is invalid. */
#define DAVQL_ERROR_INVALID_LOGICAL_OP 23
/** Invalid format specifier. */
#define DAVQL_ERROR_INVALID_FMTSPEC 24
/** A string has been expected. */
#define DAVQL_ERROR_INVALID_STRING 25
/** The order criterion is invalid (must be an identifier or field index). */
#define DAVQL_ERROR_INVALID_ORDER_CRITERION 26
/** The depth is invalid. */
#define DAVQL_ERROR_INVALID_DEPTH 101
/** Nothing about the statement seems legit. */
#define DAVQL_ERROR_INVALID -1
/** A call to malloc or calloc failed. */
#define DAVQL_ERROR_OUT_OF_MEMORY -2
/**
* Starts an interactive debugger for a DavQLStatement.
*
* @param stmt the statement to debug
*/
void dav_debug_statement(DavQLStatement *stmt);
/**
* Parses a statement.
* @param stmt the sstr_t containing the statement
* @return a DavQLStatement object
*/
DavQLStatement* dav_parse_statement(cxstring stmt);
/**
* Implicitly converts a cstr to a sstr_t and calls dav_parse_statement.
*/
#define dav_parse_cstr_statement(stmt) dav_parse_statement(cx_str(stmt))
/**
* Frees a DavQLStatement.
* @param stmt the statement object to free
*/
void dav_free_statement(DavQLStatement *stmt);
#ifdef __cplusplus
}
#endif
#endif /* DAVQLPARSER_H */