From 5e45211a64149b3c659b90ff2de6fa982a5a93ed Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 14:17:33 +0200 Subject: Adding upstream version 15.5. Signed-off-by: Daniel Baumann --- src/include/fe_utils/conditional.h | 102 +++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 src/include/fe_utils/conditional.h (limited to 'src/include/fe_utils/conditional.h') diff --git a/src/include/fe_utils/conditional.h b/src/include/fe_utils/conditional.h new file mode 100644 index 0000000..fa53d86 --- /dev/null +++ b/src/include/fe_utils/conditional.h @@ -0,0 +1,102 @@ +/*------------------------------------------------------------------------- + * A stack of automaton states to handle nested conditionals. + * + * This file describes a stack of automaton states which + * allow a manage nested conditionals. + * + * It is used by: + * - "psql" interpreter for handling \if ... \endif + * - "pgbench" interpreter for handling \if ... \endif + * - "pgbench" syntax checker to test for proper nesting + * + * The stack holds the state of enclosing conditionals (are we in + * a true branch? in a false branch? have we already encountered + * a true branch?) so that the interpreter knows whether to execute + * code and whether to evaluate conditions. + * + * Copyright (c) 2000-2022, PostgreSQL Global Development Group + * + * src/include/fe_utils/conditional.h + * + *------------------------------------------------------------------------- + */ +#ifndef CONDITIONAL_H +#define CONDITIONAL_H + +/* + * Possible states of a single level of \if block. + */ +typedef enum ifState +{ + IFSTATE_NONE = 0, /* not currently in an \if block */ + IFSTATE_TRUE, /* currently in an \if or \elif that is true + * and all parent branches (if any) are true */ + IFSTATE_FALSE, /* currently in an \if or \elif that is false + * but no true branch has yet been seen, and + * all parent branches (if any) are true */ + IFSTATE_IGNORED, /* currently in an \elif that follows a true + * branch, or the whole \if is a child of a + * false parent branch */ + IFSTATE_ELSE_TRUE, /* currently in an \else that is true and all + * parent branches (if any) are true */ + IFSTATE_ELSE_FALSE /* currently in an \else that is false or + * ignored */ +} ifState; + +/* + * The state of nested \ifs is stored in a stack. + * + * query_len is used to determine what accumulated text to throw away at the + * end of an inactive branch. (We could, perhaps, teach the lexer to not add + * stuff to the query buffer in the first place when inside an inactive branch; + * but that would be very invasive.) We also need to save and restore the + * lexer's parenthesis nesting depth when throwing away text. (We don't need + * to save and restore any of its other state, such as comment nesting depth, + * because a backslash command could never appear inside a comment or SQL + * literal.) + */ +typedef struct IfStackElem +{ + ifState if_state; /* current state, see enum above */ + int query_len; /* length of query_buf at last branch start */ + int paren_depth; /* parenthesis depth at last branch start */ + struct IfStackElem *next; /* next surrounding \if, if any */ +} IfStackElem; + +typedef struct ConditionalStackData +{ + IfStackElem *head; +} ConditionalStackData; + +typedef struct ConditionalStackData *ConditionalStack; + + +extern ConditionalStack conditional_stack_create(void); + +extern void conditional_stack_reset(ConditionalStack cstack); + +extern void conditional_stack_destroy(ConditionalStack cstack); + +extern int conditional_stack_depth(ConditionalStack cstack); + +extern void conditional_stack_push(ConditionalStack cstack, ifState new_state); + +extern bool conditional_stack_pop(ConditionalStack cstack); + +extern ifState conditional_stack_peek(ConditionalStack cstack); + +extern bool conditional_stack_poke(ConditionalStack cstack, ifState new_state); + +extern bool conditional_stack_empty(ConditionalStack cstack); + +extern bool conditional_active(ConditionalStack cstack); + +extern void conditional_stack_set_query_len(ConditionalStack cstack, int len); + +extern int conditional_stack_get_query_len(ConditionalStack cstack); + +extern void conditional_stack_set_paren_depth(ConditionalStack cstack, int depth); + +extern int conditional_stack_get_paren_depth(ConditionalStack cstack); + +#endif /* CONDITIONAL_H */ -- cgit v1.2.3