1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2018 Olaf Wintermann. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #ifndef DAVQLPARSER_H
30 #define DAVQLPARSER_H
31
32 #ifdef __cplusplus
33 extern "C" {
34 #endif
35
36 #include <stdint.h>
37 #include <cx/string.h>
38 #include <cx/list.h>
39
40 /**
41 * Enumeration of possible statement types.
42 */
43 typedef enum {DAVQL_ERROR, DAVQL_SELECT, DAVQL_SET} davqltype_t;
44
45 /**
46 * Enumeration of possible token classes.
47 */
48 typedef enum {
49 DAVQL_TOKEN_INVALID, DAVQL_TOKEN_KEYWORD,
50 DAVQL_TOKEN_IDENTIFIER, DAVQL_TOKEN_FMTSPEC,
51 DAVQL_TOKEN_STRING, DAVQL_TOKEN_NUMBER, DAVQL_TOKEN_TIMESTAMP,
52 DAVQL_TOKEN_COMMA, DAVQL_TOKEN_OPENP, DAVQL_TOKEN_CLOSEP,
53 DAVQL_TOKEN_OPERATOR, DAVQL_TOKEN_END
54 } davqltokenclass_t;
55
56 /**
57 * Enumeration of possible expression types.
58 */
59 typedef enum {
60 DAVQL_UNDEFINED_TYPE,
61 DAVQL_NUMBER, DAVQL_STRING, DAVQL_TIMESTAMP, DAVQL_IDENTIFIER,
62 DAVQL_UNARY, DAVQL_BINARY, DAVQL_LOGICAL, DAVQL_FUNCCALL
63 } davqlexprtype_t;
64
65 /**
66 * Enumeration of possible expression operators.
67 */
68 typedef enum {
69 DAVQL_NOOP, DAVQL_CALL, DAVQL_ARGLIST, // internal representations
70 DAVQL_ADD, DAVQL_SUB, DAVQL_MUL, DAVQL_DIV,
71 DAVQL_AND, DAVQL_OR, DAVQL_XOR, DAVQL_NEG, // airthmetic
72 DAVQL_NOT, DAVQL_LAND, DAVQL_LOR, DAVQL_LXOR, // logical
73 DAVQL_EQ, DAVQL_NEQ, DAVQL_LT, DAVQL_GT, DAVQL_LE, DAVQL_GE,
74 DAVQL_LIKE, DAVQL_UNLIKE // comparisons
75 } davqloperator_t;
76
77 typedef struct DavQLToken DavQLToken;
78 struct DavQLToken {
79 davqltokenclass_t tokenclass;
80 cxstring value;
81 DavQLToken *prev;
82 DavQLToken *next;
83 };
84
85 /**
86 * An expression within a DAVQL query.
87 */
88 typedef struct _davqlexpr DavQLExpression;
89
90 /**
91 * The structure for type DavQLExpression.
92 */
93 struct _davqlexpr {
94 /**
95 * The original expression text.
96 * Contains the literal value, if type is LITERAL.
97 */
98 cxstring srctext;
99 /**
100 * The expression type.
101 */
102 davqlexprtype_t type;
103 /**
104 * Operator.
105 */
106 davqloperator_t op;
107 /**
108 * Left or single operand.
109 * <code>NULL</code> for literals or identifiers.
110 */
111 DavQLExpression *left;
112 /**
113 * Right operand.
114 * <code>NULL</code> for literals, identifiers or unary expressions.
115 */
116 DavQLExpression *right;
117 };
118
119 /**
120 * A tuple representing an order criterion.
121 */
122 typedef struct {
123 /**
124 * The column.
125 */
126 DavQLExpression *column;
127 /**
128 * True, if the result shall be sorted descending, false otherwise.
129 * Default is false (ascending).
130 */
131 _Bool descending;
132 } DavQLOrderCriterion;
133
134 /**
135 * A tuple representing a field.
136 */
137 typedef struct {
138 /**
139 * The field name.
140 * <ul>
141 * <li>SELECT: the identifier or an alias name</li>
142 * <li>SET: the identifier</li>
143 * </ul>
144 */
145 cxstring name;
146 /**
147 * The field expression.
148 * <ul>
149 * <li>SELECT: the queried property (identifier) or an expression</li>
150 * <li>SET: the expression for the value to be set</li>
151 * </ul>
152 */
153 DavQLExpression *expr;
154 } DavQLField;
155
156 /**
157 * Query statement object.
158 * Contains the binary information about the parsed query.
159 *
160 * The grammar for a DavQLStatement is:
161 *
162 * <pre>
163 * Keyword = "select" | "set" | "from" | "at" | "as"
164 * | "where" | "anywhere" | "like" | "unlike"
165 * | "and" | "or" | "not" | "xor" | "with" | "infinity"
166 * | "order" | "by" | "asc" | "desc";
167 *
168 * Expression = AddExpression;
169 * AddExpression = MultExpression, [AddOperator, AddExpression];
170 * MultExpression = BitwiseExpression, [MultOperator, MultExpression];
171 * BitwiseExpression = UnaryExpression, [BitwiseOperator, BitwiseExpression];
172 * UnaryExpression = [UnaryOperator], (ParExpression | AtomicExpression);
173 * AtomicExpression = FunctionCall | Identifier | Literal;
174 * ParExpression = "(", Expression, ")";
175 *
176 * BitwiseOperator = "&" | "|" | "^";
177 * MultOperator = "*" | "/";
178 * AddOperator = "+" | "-";
179 * UnaryOperator = "+" | "-" | "~";
180 *
181 * FunctionCall = Identifier, "(", [ArgumentList], ")";
182 * ArgumentList = Expression, {",", Expression};
183 * Identifier = IdentifierChar - ?Digit?, {IdentifierChar}
184 * | "`", ?Character? - "`", {?Character? - "`"}, "`";
185 * IdentifierChar = ?Character? - (" "|",");
186 * Literal = Number | String | Timestamp;
187 * Number = ?Digit?, {?Digit?} | "%d";
188 * String = "'", {?Character? - "'" | "'''"} , "'" | "%s";
189 * Timestamp = "%t"; // TODO: maybe introduce a real literal
190 *
191 * LogicalExpression = BooleanExpression, [LogicalOperator, LogicalExpression];
192 * BooleanExpression = "not ", BooleanExpression
193 * | "(", LogicalExpression, ")"
194 * | BooleanPrimary;
195 * BooleanPrimary = Expression, (" like " | " unlike "), String
196 * | Expression, Comparison, Expression
197 * | FunctionCall | Identifier;
198 *
199 * LogicalOperator = " and " | " or " | " xor ";
200 * Comparison = | "=" | "<" | ">" | "<=" | ">=" | "!=";
201 *
202 * FieldExpressions = "-"
203 * | "*", {",", NamedField}
204 * | FieldExpression, {",", FieldExpression};
205 * FieldExpression = NamedField | Identifier;
206 * NamedField = Expression, " as ", Identifier;
207 *
208 * Assignments = Assignment, {",", Assignment};
209 * Assignment = Identifier, "=", Expression;
210 *
211 * Path = String
212 * | "/", [PathNode, {"/", PathNode}], ["/"];
213 * PathNode = {{?Character? - "/"} - Keyword};
214 *
215 * WithClause = "depth", "=", (Number | "infinity");
216 *
217 * OrderByClause = OrderByCriterion, {",", OrderByCriterion};
218 * OrderByCriterion = (Identifier | Number), [" asc"|" desc"];
219 *
220 * </pre>
221 *
222 * Note: mandatory spaces are part of the grammar. But you may also insert an
223 * arbitrary amount of optional spaces between two symbols if they are not part
224 * of an literal, identifier or the path.
225 *
226 * <b>SELECT:</b>
227 * <pre>
228 * SelectStatement = "select ", FieldExpressions,
229 * " from ", Path,
230 * [" with ", WithClause],
231 * [(" where ", LogicalExpression) | " anywhere"],
232 * [" order by ", OrderByClause];
233 * </pre>
234 *
235 * <b>SET:</b>
236 * <pre>
237 * SetStatement = "set ",Assignments,
238 * " at ", Path,
239 * [" with ", WithClause],
240 * (" where ", LogicalExpression) | " anywhere";
241 * </pre>
242 *
243 */
244 typedef struct {
245 /**
246 * The original query text.
247 */
248 cxstring srctext;
249 /**
250 * The statement type.
251 */
252 davqltype_t type;
253 /**
254 * Error code, if any error occurred. Zero otherwise.
255 */
256 int errorcode;
257 /**
258 * Error message, if any error occurred.
259 */
260 char* errormessage;
261 /**
262 * The list of DavQLFields.
263 */
264 CxList* fields;
265 /**
266 * A string that denotes the queried path.
267 */
268 cxstring path;
269 /**
270 * Logical expression for selection.
271 * <code>NULL</code>, if there is no where clause.
272 */
273 DavQLExpression* where;
274 /**
275 * The list of DavQLOrderCriterions.
276 * This is <code>NULL</code> for SET queries and may be <code>NULL</code>
277 * if the result doesn't need to be sorted.
278 */
279 CxList* orderby;
280 /**
281 * The recursion depth for the statement.
282 * Defaults to 1.
283 * Magic numbers are DAV_DEPTH_INFINITY for infinity and
284 * DAV_DEPTH_PLACEHOLDER for a placeholder.
285 */
286 int depth;
287 /**
288 * A list of all required arguments
289 */
290 CxList* args;
291 } DavQLStatement;
292
293 /** Infinity recursion depth for a DavQLStatement. */
294 #define DAV_DEPTH_INFINITY -1
295
296 /** Depth needs to be specified at runtime. */
297 #define DAV_DEPTH_PLACEHOLDER -2
298
299 /** Unexpected token. */
300 #define DAVQL_ERROR_UNEXPECTED_TOKEN 1
301
302 /** A token has been found, for which no token class is applicable. */
303 #define DAVQL_ERROR_INVALID_TOKEN 2
304
305 /** A token that has been expected was not found. */
306 #define DAVQL_ERROR_MISSING_TOKEN 11
307
308 /** An expression has been expected, but was not found. */
309 #define DAVQL_ERROR_MISSING_EXPR 12
310
311 /** A closed parenthesis ')' is missing. */
312 #define DAVQL_ERROR_MISSING_PAR 13
313
314 /** An assignment operator '=' is missing. */
315 #define DAVQL_ERROR_MISSING_ASSIGN 14
316
317 /** The type of the expression could not be determined. */
318 #define DAVQL_ERROR_INVALID_EXPR 21
319
320 /** An operator has been found for an unary expression, but it is invalid. */
321 #define DAVQL_ERROR_INVALID_UNARY_OP 22
322
323 /** An operator has been found for a logical expression, but it is invalid. */
324 #define DAVQL_ERROR_INVALID_LOGICAL_OP 23
325
326 /** Invalid format specifier. */
327 #define DAVQL_ERROR_INVALID_FMTSPEC 24
328
329 /** A string has been expected. */
330 #define DAVQL_ERROR_INVALID_STRING 25
331
332 /** The order criterion is invalid (must be an identifier or field index). */
333 #define DAVQL_ERROR_INVALID_ORDER_CRITERION 26
334
335 /** The depth is invalid. */
336 #define DAVQL_ERROR_INVALID_DEPTH 101
337
338 /** Nothing about the statement seems legit. */
339 #define DAVQL_ERROR_INVALID -1
340
341 /** A call to malloc or calloc failed. */
342 #define DAVQL_ERROR_OUT_OF_MEMORY -2
343
344 /**
345 * Starts an interactive debugger for a DavQLStatement.
346 *
347 * @param stmt the statement to debug
348 */
349 void dav_debug_statement(DavQLStatement *stmt);
350
351 /**
352 * Parses a statement.
353 * @param stmt the sstr_t containing the statement
354 * @return a DavQLStatement object
355 */
356 DavQLStatement* dav_parse_statement(cxstring stmt);
357
358 /**
359 * Implicitly converts a cstr to a sstr_t and calls dav_parse_statement.
360 */
361 #define dav_parse_cstr_statement(stmt) dav_parse_statement(cx_str(stmt))
362
363 /**
364 * Frees a DavQLStatement.
365 * @param stmt the statement object to free
366 */
367 void dav_free_statement(DavQLStatement *stmt);
368
369 #ifdef __cplusplus
370 }
371 #endif
372
373 #endif /* DAVQLPARSER_H */
374
375