src/bin/psql/variables.h

   1 /*
   2  * psql - the PostgreSQL interactive terminal
   3  *
   4  * Copyright (c) 2000-2008, PostgreSQL Global Development Group
   5  *
   6  * $PostgreSQL$
   7  */
   8 #ifndef VARIABLES_H
   9 #define VARIABLES_H
  10
  11 /*
  12  * This implements a sort of variable repository. One could also think of it
  13  * as a cheap version of an associative array. In each one of these
  14  * datastructures you can store name/value pairs.  There can also be an
  15  * "assign hook" function that is called whenever the variable's value is
  16  * changed.
  17  *
  18  * An "unset" operation causes the hook to be called with newval == NULL.
  19  *
  20  * Note: if value == NULL then the variable is logically unset, but we are
  21  * keeping the struct around so as not to forget about its hook function.
  22  */
  23 typedef void (*VariableAssignHook) (const char *newval);
  24
  25 struct _variable
  26 {
  27         char       *name;
  28         char       *value;
  29         VariableAssignHook assign_hook;
  30         struct _variable *next;
  31 };
  32
  33 typedef struct _variable *VariableSpace;
  34
  35 /* Allowed chars in a variable's name */
  36 #define VALID_VARIABLE_CHARS "abcdefghijklmnopqrstuvwxyz"\
  37                                                          "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "0123456789_"
  38
  39 VariableSpace CreateVariableSpace(void);
  40 const char *GetVariable(VariableSpace space, const char *name);
  41
  42 bool            ParseVariableBool(const char *val);
  43 int ParseVariableNum(const char *val,
  44                                  int defaultval,
  45                                  int faultval,
  46                                  bool allowtrail);
  47 int GetVariableNum(VariableSpace space,
  48                            const char *name,
  49                            int defaultval,
  50                            int faultval,
  51                            bool allowtrail);
  52
  53 void            PrintVariables(VariableSpace space);
  54
  55 bool            SetVariable(VariableSpace space, const char *name, const char *value);
  56 bool            SetVariableAssignHook(VariableSpace space, const char *name, VariableAssignHook hook);
  57 bool            SetVariableBool(VariableSpace space, const char *name);
  58 bool            DeleteVariable(VariableSpace space, const char *name);
  59
  60 #endif   /* VARIABLES_H */