f67b113ac6
Patch adds \if to pgbench as it done for psql. Implementation shares condition stack code with psql, so, this code is moved to fe_utils directory. Author: Fabien COELHO with minor editorization by me Review by: Vik Fearing, Fedor Sigaev Discussion: https://www.postgresql.org/message-id/flat/alpine.DEB.2.20.1711252200190.28523@lancre
101 lines
3.6 KiB
C
101 lines
3.6 KiB
C
/*-------------------------------------------------------------------------
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* A stack of automaton states to handle nested conditionals.
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*
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* This file describes a stack of automaton states which
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* allow a manage nested conditionals.
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*
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* It is used by:
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* - "psql" interpretor for handling \if ... \endif
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* - "pgbench" interpretor for handling \if ... \endif
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* - "pgbench" syntax checker to test for proper nesting
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*
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* The stack holds the state of enclosing conditionals (are we in
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* a true branch? in a false branch? have we already encountered
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* a true branch?) so that the interpreter knows whether to execute
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* code and whether to evaluate conditions.
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*
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* Copyright (c) 2000-2018, PostgreSQL Global Development Group
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*
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* src/include/fe_utils/conditional.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef CONDITIONAL_H
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#define CONDITIONAL_H
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/*
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* Possible states of a single level of \if block.
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*/
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typedef enum ifState
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{
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IFSTATE_NONE = 0, /* not currently in an \if block */
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IFSTATE_TRUE, /* currently in an \if or \elif that is true
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* and all parent branches (if any) are true */
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IFSTATE_FALSE, /* currently in an \if or \elif that is false
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* but no true branch has yet been seen, and
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* all parent branches (if any) are true */
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IFSTATE_IGNORED, /* currently in an \elif that follows a true
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* branch, or the whole \if is a child of a
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* false parent branch */
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IFSTATE_ELSE_TRUE, /* currently in an \else that is true and all
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* parent branches (if any) are true */
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IFSTATE_ELSE_FALSE /* currently in an \else that is false or
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* ignored */
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} ifState;
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/*
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* The state of nested \ifs is stored in a stack.
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*
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* query_len is used to determine what accumulated text to throw away at the
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* end of an inactive branch. (We could, perhaps, teach the lexer to not add
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* stuff to the query buffer in the first place when inside an inactive branch;
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* but that would be very invasive.) We also need to save and restore the
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* lexer's parenthesis nesting depth when throwing away text. (We don't need
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* to save and restore any of its other state, such as comment nesting depth,
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* because a backslash command could never appear inside a comment or SQL
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* literal.)
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*/
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typedef struct IfStackElem
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{
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ifState if_state; /* current state, see enum above */
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int query_len; /* length of query_buf at last branch start */
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int paren_depth; /* parenthesis depth at last branch start */
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struct IfStackElem *next; /* next surrounding \if, if any */
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} IfStackElem;
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typedef struct ConditionalStackData
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{
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IfStackElem *head;
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} ConditionalStackData;
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typedef struct ConditionalStackData *ConditionalStack;
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extern ConditionalStack conditional_stack_create(void);
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extern void conditional_stack_destroy(ConditionalStack cstack);
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extern int conditional_stack_depth(ConditionalStack cstack);
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extern void conditional_stack_push(ConditionalStack cstack, ifState new_state);
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extern bool conditional_stack_pop(ConditionalStack cstack);
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extern ifState conditional_stack_peek(ConditionalStack cstack);
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extern bool conditional_stack_poke(ConditionalStack cstack, ifState new_state);
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extern bool conditional_stack_empty(ConditionalStack cstack);
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extern bool conditional_active(ConditionalStack cstack);
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extern void conditional_stack_set_query_len(ConditionalStack cstack, int len);
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extern int conditional_stack_get_query_len(ConditionalStack cstack);
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extern void conditional_stack_set_paren_depth(ConditionalStack cstack, int depth);
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extern int conditional_stack_get_paren_depth(ConditionalStack cstack);
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#endif /* CONDITIONAL_H */
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