rvalue.h
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 /* 
  * Copyright (C) 2008 iptelorg GmbH
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
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 /**
  * @file 
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  * @brief Kamailio core :: rvalue expressions
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  * @ingroup core
  * Module: \ref core
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  * @author andrei
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  */
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 #ifndef _rvalue_h_
 #define _rvalue_h_
 
 #include "str.h"
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 #include "ut.h"
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 #include "usr_avp.h"
 #include "select.h"
 #include "pvar.h"
 #include "route.h"
 #include "parser/msg_parser.h"
 #include "action.h"
 
 enum rval_type{
 	RV_NONE, RV_INT, RV_STR, /* basic types */
 	RV_BEXPR, RV_ACTION_ST,  /* special values */
 	RV_SEL, RV_AVP, RV_PVAR
 };
 
 enum rval_expr_op{
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 	RVE_NONE_OP,  /**< uninit / empty */
 	RVE_RVAL_OP,  /**< special op, means that the expr. is in fact a rval */
 	RVE_UMINUS_OP, /**< one member expression, returns -(val) */
 	RVE_BOOL_OP,  /**< one member evaluate as bool. : (val!=0)*/
 	RVE_LNOT_OP,  /**< one member evaluate as bool. : (!val)*/
 	RVE_BNOT_OP,  /**< one member evaluate as binary : (~ val)*/
 	RVE_MUL_OP,   /**< 2 members, returns left * right */
 	RVE_DIV_OP,   /**< 2 members, returns left / right */
 	RVE_MOD_OP,   /**< 2 members, returns left % right */
 	RVE_MINUS_OP, /**< 2 members, returns left - right */
 	RVE_BAND_OP,  /**< 2 members, returns left | right */
 	RVE_BOR_OP,   /**< 2 members, returns left & right */
 	RVE_BXOR_OP,   /**< 2 members, returns left XOR right */
 	RVE_BLSHIFT_OP, /**< 2 members, returns left << right */
 	RVE_BRSHIFT_OP, /**< 2 members, returns left >> right */
 	RVE_LAND_OP,  /**< 2 members, returns left && right */
 	RVE_LOR_OP,   /**< 2 members, returns left || right */
 	RVE_GT_OP,    /**<  2 members, returns left > right */
 	RVE_GTE_OP,   /**<  2 members, returns left >= right */
 	RVE_LT_OP,    /**<  2 members, returns left  < right */
 	RVE_LTE_OP,   /**<  2 members, returns left <= right */
 	RVE_IEQ_OP,   /**<  2 members, int == version, returns left == right */
 	RVE_IDIFF_OP, /**< 2 members, int != version, returns left != right */
 	RVE_IPLUS_OP, /**< 2 members, integer +, returns int(a)+int(b) */
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 	/* common int & str */
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 	RVE_PLUS_OP,  /**< generic plus (int or str) returns left + right */
 	RVE_EQ_OP,    /**<  2 members, returns left == right  (int)*/
 	RVE_DIFF_OP,  /**<  2 members, returns left != right  (int)*/
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 	/* str only */
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 	RVE_CONCAT_OP, /**< 2 members, string concat, returns left . right (str)*/
 	RVE_STRLEN_OP, /**< one member, string length:, returns strlen(val) (int)*/
 	RVE_STREMPTY_OP, /**< one member, returns val=="" (bool) */
 	RVE_STREQ_OP,  /**< 2 members, string == , returns left == right (bool)*/
 	RVE_STRDIFF_OP,/**< 2 members, string != , returns left != right (bool)*/
 	RVE_MATCH_OP,  /**< 2 members, string ~),  returns left matches re(right) */
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 	/* avp, pvars a.s.o */
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 	RVE_DEFINED_OP, /**< one member, returns is_defined(val) (bool) */
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 	RVE_NOTDEFINED_OP, /**< one member, returns is_not_defined(val) (bool) */
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 	RVE_INT_OP,   /**< one member, returns (int)val  (int) */
 	RVE_STR_OP    /**< one member, returns (str)val  (str) */
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 };
 
 
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 struct str_re{
 	str s;
 	regex_t* regex;
 };
 
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 union rval_val{
 	void* p;
 	long  l;
 	str s;
 	avp_spec_t avps;
 	select_t sel;
 	pv_spec_t pvs;
 	struct action* action;
 	struct expr* bexpr;
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 	struct str_re re;
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 };
 
 
 struct rvalue{
 	enum rval_type type;
 	int refcnt; /**< refcnt, on 0 the structure is destroyed */
 	union rval_val v;
 	int bsize; /**< extra data size */
 	short flags;
 	char buf[1]; /**< extra data, like string contents can be stored here */
 };
 
 
 /* rvalue flags */
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 #define RV_CNT_ALLOCED_F  1  /**< free contents  (pkg mem allocated) */
 #define RV_RV_ALLOCED_F   2  /**< free rv itself (pkg_free(rv)) */
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 #define RV_ALL_ALLOCED_F  (RV_CNT_ALLOCED|RV_RV_ALLOCED)
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 #define RV_RE_F  4 /**< string is a RE with a valid v->re member */
 #define RV_RE_ALLOCED_F 8 /**< v->re.regex must be freed */
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 struct rval_expr{
 	enum rval_expr_op op;
 	union{
 		struct rval_expr* rve;
 		struct rvalue rval;
 	}left;
 	union{
 		struct rval_expr* rve;
 		struct rvalue rval;
 	}right;
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 	struct cfg_pos fpos;
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 };
 
 
 enum rval_cache_type{
 	RV_CACHE_EMPTY,
 	RV_CACHE_PVAR,
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 	RV_CACHE_AVP,
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 	RV_CACHE_SELECT,
 	RV_CACHE_INT2STR
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 };
 
 /** value cache for a rvalue struct.
   * Used to optimize functions that would need to 
   * get the value repeatedly (e.g. rval_get_btype() and then rval_get_int())
   */
 struct rval_cache{
 	enum rval_cache_type cache_type;
 	enum rval_type val_type;
 	union{
 		int_str avp_val; /**< avp value */
 		pv_value_t pval; /**< pvar value */
 	}c;
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 	char i2s[INT2STR_MAX_LEN]; /**< space for converting an int to string*/
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 };
 
 
 
 /** allocates a new rval (should be freed by rval_destroy()). */
 struct rvalue* rval_new_empty(int extra_size);
 struct rvalue* rval_new_str(str* s, int extra_size);
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 /**
  * @brief create a new pk_malloc'ed rvalue from a rval_val union
  * @param t rvalue type
  * @param v rvalue value
  * @param extra_size extra space to allocate
  * (so that future string operation can reuse the space)
  * @return new rv or 0 on error
  */
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 struct rvalue* rval_new(enum rval_type t, union rval_val* v, int extra_size);
 
 /** inits a rvalue structure- */
 void rval_init(struct rvalue* rv, enum rval_type t, union rval_val* v,
 					int flags);
 /** frees a rval_new(), rval_convert() or rval_expr_eval() returned rval. */
 void rval_destroy(struct rvalue* rv);
 
 /** frees a rval contents */
 void rval_clean(struct rvalue* rv);
 
 /** init a rval_cache struct */
 #define rval_cache_init(rvc) \
 	do{ (rvc)->cache_type=RV_CACHE_EMPTY; (rvc)->val_type=RV_NONE; }while(0)
 
 /** destroy a rval_cache struct contents */
 void rval_cache_clean(struct rval_cache* rvc);
 
 
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 /**
  * @brief Convert a rvalue to another rvalue, of a specific type
  *
  * Convert a rvalue to another rvalue, of a specific type.
  * The result is read-only in most cases (can be a reference
  * to another rvalue, can be checked by using rv_chg_in_place()) and
  * _must_ be rval_destroy()'ed.
  *
  * @param h run action context
  * @param msg SIP mesasge
  * @param type - type to convert to
  * @param v - rvalue to convert
  * @param c - rval_cache (cached v value if known/filled by another
  *            function), can be 0 (unknown/not needed)
  * @return pointer to a rvalue (reference to an existing one or a new
  * one, @see rv_chg_in_place() and the above comment), or 0 on error.
  */
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 struct rvalue* rval_convert(struct run_act_ctx* h, struct sip_msg* msg, 
 							enum rval_type type, struct rvalue* v,
 							struct rval_cache* c);
 
 /** get the integer value of an rvalue. */
 int rval_get_int(struct run_act_ctx* h, struct sip_msg* msg, int* i, 
 				struct rvalue* rv, struct rval_cache* cache);
 /** get the string value of an rv. */
 int rval_get_str(struct run_act_ctx* h, struct sip_msg* msg,
 								str* s, struct rvalue* rv,
 								struct rval_cache* cache);
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 /** get the string value of an rv in a tmp variable */
 int rval_get_tmp_str(struct run_act_ctx* h, struct sip_msg* msg,
 								str* tmpv, struct rvalue* rv,
 								struct rval_cache* cache,
 								struct rval_cache* tmp_cache);
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 /** evals an integer expr  to an int. */
 int rval_expr_eval_int( struct run_act_ctx* h, struct sip_msg* msg,
 						int* res, struct rval_expr* rve);
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 /**
  * @brief Evals a rval expression
  * @warning result must be rval_destroy()'ed if non-null (it might be
  * a reference to another rval). The result can be modified only
  * if rv_chg_in_place() returns true.
  * @param h run action context
  * @param msg SIP message
  * @param rve rvalue expression
  * @return rvalue on success, 0 on error
  */
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 struct rvalue* rval_expr_eval(struct run_act_ctx* h, struct sip_msg* msg,
 								struct rval_expr* rve);
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 /**
  * @brief Evals a rval expression into an int or another rv(str)
  * @warning rv result (rv_res) must be rval_destroy()'ed if non-null
  * (it might be a reference to another rval). The result can be
  * modified only if rv_chg_in_place() returns true.
  * @param h run action context
  * @param msg SIP message
  * @param res_rv pointer to rvalue result, if non-null it means the 
  * expression evaluated to a non-int (str), which will be stored here.
  * @param res_i pointer to int result, if res_rv==0 and the function
  * returns success => the result is an int which will be stored here.
  * @param rve expression that will be evaluated.
  * @param cache write-only value cache, it might be filled if non-null and
  * empty (rval_cache_init()). If non-null, it _must_ be rval_cache_clean()'ed
  * when done. 
  * @return 0 on success, -1 on error, sets *res_rv or *res_i.
  */
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 int rval_expr_eval_rvint( struct run_act_ctx* h, struct sip_msg* msg,
 						 struct rvalue** rv_res, int* i_res,
 						 struct rval_expr* rve, struct rval_cache* cache);
 
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 /** guess the type of an expression.  */
 enum rval_type rve_guess_type(struct rval_expr* rve);
 /** returns true if expression is constant. */
 int rve_is_constant(struct rval_expr* rve);
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 /** returns true if the expression can have side-effect */
 int rve_has_side_effects(struct rval_expr* rve);
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 /**
  * @brief Returns 1 if expression is valid (type-wise)
  * @param type filled with the type of the expression (RV_INT, RV_STR or
  *                RV_NONE if it's dynamic)
  * @param rve  checked expression
  * @param bad_rve set on failure to the subexpression for which the 
  * type check failed
  * @param bad_t set on failure to the type of the bad subexpression
  * @param exp_t set on failure to the expected type for the bad
  * subexpression
  * @return 0 or 1 and sets *type to the resulting type
  * (RV_INT, RV_STR or RV_NONE if it can be found only at runtime)
  */
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 int rve_check_type(enum rval_type* type, struct rval_expr* rve,
 					struct rval_expr** bad_rve, enum rval_type* bad_type,
 					enum rval_type* exp_type);
 /** returns a string name for type (debugging).*/
 char* rval_type_name(enum rval_type type);
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 /** create a RVE_RVAL_OP rval_expr, containing a single rval of the given type
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   */
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 struct rval_expr* mk_rval_expr_v(enum rval_type rv_type, void* val,
 									struct cfg_pos* pos);
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 /**
  * @brief Create a unary op. rval_expr
  * ret= op rve1
  * @param op   - rval expr. unary operator
  * @param rve1 - rval expr. on which the operator will act.
  * @param pos configuration position
  * @return new pkg_malloc'ed rval_expr or 0 on error.
  */
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 struct rval_expr* mk_rval_expr1(enum rval_expr_op op, struct rval_expr* rve1,
 									struct cfg_pos* pos);
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 /**
  * @brief Create a rval_expr. from 2 other rval exprs, using op
  * ret = rve1 op rve2
  * @param op   - rval expr. operator
  * @param rve1 - rval expr. on which the operator will act.
  * @param rve2 - rval expr. on which the operator will act.
  * @param pos configuration position
  * @return new pkg_malloc'ed rval_expr or 0 on error.
  */
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 struct rval_expr* mk_rval_expr2(enum rval_expr_op op, struct rval_expr* rve1,
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 													  struct rval_expr* rve2,
 													  struct cfg_pos* pos);
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 /** destroys a pkg_malloc'ed rve. */
 void rve_destroy(struct rval_expr* rve);
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 /** fix a rval_expr. */
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 int fix_rval_expr(void* p);
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 #endif /* _rvalue_h */