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parse_tree.go
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/
parse_tree.go
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package influxql
import (
"fmt"
)
var Language = &ParseTree{}
type ParseTree struct {
Handlers map[Token]func(*Parser) (Statement, error)
Tokens map[Token]*ParseTree
Keys []string
}
// With passes the current parse tree to a function to allow nested functions.
func (t *ParseTree) With(fn func(*ParseTree)) {
fn(t)
}
// Group groups together a set of related handlers with a common token prefix.
func (t *ParseTree) Group(tokens ...Token) *ParseTree {
for _, tok := range tokens {
// Look for the parse tree for this token.
if subtree := t.Tokens[tok]; subtree != nil {
t = subtree
continue
}
// No subtree exists yet. Verify that we don't have a conflicting
// statement.
if _, conflict := t.Handlers[tok]; conflict {
panic(fmt.Sprintf("conflict for token %s", tok))
}
// Create the new parse tree and register it inside of this one for
// later reference.
newT := &ParseTree{}
if t.Tokens == nil {
t.Tokens = make(map[Token]*ParseTree)
}
t.Tokens[tok] = newT
t.Keys = append(t.Keys, tok.String())
t = newT
}
return t
}
// Handle registers a handler to be invoked when seeing the given token.
func (t *ParseTree) Handle(tok Token, fn func(*Parser) (Statement, error)) {
// Verify that there is no conflict for this token in this parse tree.
if _, conflict := t.Tokens[tok]; conflict {
panic(fmt.Sprintf("conflict for token %s", tok))
}
if _, conflict := t.Handlers[tok]; conflict {
panic(fmt.Sprintf("conflict for token %s", tok))
}
if t.Handlers == nil {
t.Handlers = make(map[Token]func(*Parser) (Statement, error))
}
t.Handlers[tok] = fn
t.Keys = append(t.Keys, tok.String())
}
// Parse parses a statement using the language defined in the parse tree.
func (t *ParseTree) Parse(p *Parser) (Statement, error) {
for {
tok, pos, lit := p.ScanIgnoreWhitespace()
if subtree := t.Tokens[tok]; subtree != nil {
t = subtree
continue
}
if stmt := t.Handlers[tok]; stmt != nil {
return stmt(p)
}
// There were no registered handlers. Return the valid tokens in the order they were added.
return nil, newParseError(tokstr(tok, lit), t.Keys, pos)
}
}
func (t *ParseTree) Clone() *ParseTree {
newT := &ParseTree{}
if t.Handlers != nil {
newT.Handlers = make(map[Token]func(*Parser) (Statement, error), len(t.Handlers))
for tok, handler := range t.Handlers {
newT.Handlers[tok] = handler
}
}
if t.Tokens != nil {
newT.Tokens = make(map[Token]*ParseTree, len(t.Tokens))
for tok, subtree := range t.Tokens {
newT.Tokens[tok] = subtree.Clone()
}
}
return newT
}
func init() {
Language.Handle(SELECT, func(p *Parser) (Statement, error) {
return p.parseSelectStatement(targetNotRequired)
})
Language.Handle(DELETE, func(p *Parser) (Statement, error) {
return p.parseDeleteStatement()
})
Language.Group(SHOW).With(func(show *ParseTree) {
show.Group(CONTINUOUS).Handle(QUERIES, func(p *Parser) (Statement, error) {
return p.parseShowContinuousQueriesStatement()
})
show.Handle(DATABASES, func(p *Parser) (Statement, error) {
return p.parseShowDatabasesStatement()
})
show.Handle(DIAGNOSTICS, func(p *Parser) (Statement, error) {
return p.parseShowDiagnosticsStatement()
})
show.Group(FIELD).With(func(field *ParseTree) {
field.Handle(KEY, func(p *Parser) (Statement, error) {
return p.parseShowFieldKeyCardinalityStatement()
})
field.Handle(KEYS, func(p *Parser) (Statement, error) {
return p.parseShowFieldKeysStatement()
})
})
show.Group(GRANTS).Handle(FOR, func(p *Parser) (Statement, error) {
return p.parseGrantsForUserStatement()
})
show.Group(MEASUREMENT).Handle(EXACT, func(p *Parser) (Statement, error) {
return p.parseShowMeasurementCardinalityStatement(true)
})
show.Group(MEASUREMENT).Handle(CARDINALITY, func(p *Parser) (Statement, error) {
return p.parseShowMeasurementCardinalityStatement(false)
})
show.Handle(MEASUREMENTS, func(p *Parser) (Statement, error) {
return p.parseShowMeasurementsStatement()
})
show.Handle(QUERIES, func(p *Parser) (Statement, error) {
return p.parseShowQueriesStatement()
})
show.Group(RETENTION).Handle(POLICIES, func(p *Parser) (Statement, error) {
return p.parseShowRetentionPoliciesStatement()
})
show.Handle(SERIES, func(p *Parser) (Statement, error) {
return p.parseShowSeriesStatement()
})
show.Handle(SERVERS, func(p *Parser) (Statement, error) {
return p.parseShowServersStatement()
})
show.Group(SHARD).Handle(GROUPS, func(p *Parser) (Statement, error) {
return p.parseShowShardGroupsStatement()
})
show.Handle(SHARDS, func(p *Parser) (Statement, error) {
return p.parseShowShardsStatement()
})
show.Handle(STATS, func(p *Parser) (Statement, error) {
return p.parseShowStatsStatement()
})
show.Handle(SUBSCRIPTIONS, func(p *Parser) (Statement, error) {
return p.parseShowSubscriptionsStatement()
})
show.Group(TAG).With(func(tag *ParseTree) {
tag.Handle(KEY, func(p *Parser) (Statement, error) {
return p.parseShowTagKeyCardinalityStatement()
})
tag.Handle(KEYS, func(p *Parser) (Statement, error) {
return p.parseShowTagKeysStatement()
})
tag.Handle(VALUES, func(p *Parser) (Statement, error) {
return p.parseShowTagValuesStatement()
})
})
show.Handle(USERS, func(p *Parser) (Statement, error) {
return p.parseShowUsersStatement()
})
})
Language.Group(CREATE).With(func(create *ParseTree) {
create.Group(CONTINUOUS).Handle(QUERY, func(p *Parser) (Statement, error) {
return p.parseCreateContinuousQueryStatement()
})
create.Handle(DATABASE, func(p *Parser) (Statement, error) {
return p.parseCreateDatabaseStatement()
})
create.Handle(USER, func(p *Parser) (Statement, error) {
return p.parseCreateUserStatement()
})
create.Group(RETENTION).Handle(POLICY, func(p *Parser) (Statement, error) {
return p.parseCreateRetentionPolicyStatement()
})
create.Handle(SUBSCRIPTION, func(p *Parser) (Statement, error) {
return p.parseCreateSubscriptionStatement()
})
})
Language.Group(DROP).With(func(drop *ParseTree) {
drop.Group(CONTINUOUS).Handle(QUERY, func(p *Parser) (Statement, error) {
return p.parseDropContinuousQueryStatement()
})
drop.Handle(DATABASE, func(p *Parser) (Statement, error) {
return p.parseDropDatabaseStatement()
})
drop.Handle(MEASUREMENT, func(p *Parser) (Statement, error) {
return p.parseDropMeasurementStatement()
})
drop.Group(RETENTION).Handle(POLICY, func(p *Parser) (Statement, error) {
return p.parseDropRetentionPolicyStatement()
})
drop.Handle(SERIES, func(p *Parser) (Statement, error) {
return p.parseDropSeriesStatement()
})
drop.Handle(SHARD, func(p *Parser) (Statement, error) {
return p.parseDropShardStatement()
})
drop.Handle(SUBSCRIPTION, func(p *Parser) (Statement, error) {
return p.parseDropSubscriptionStatement()
})
drop.Handle(USER, func(p *Parser) (Statement, error) {
return p.parseDropUserStatement()
})
})
Language.Handle(EXPLAIN, func(p *Parser) (Statement, error) {
return p.parseExplainStatement()
})
Language.Handle(GRANT, func(p *Parser) (Statement, error) {
return p.parseGrantStatement()
})
Language.Handle(REVOKE, func(p *Parser) (Statement, error) {
return p.parseRevokeStatement()
})
Language.Group(ALTER, RETENTION).Handle(POLICY, func(p *Parser) (Statement, error) {
return p.parseAlterRetentionPolicyStatement()
})
Language.Group(SET, PASSWORD).Handle(FOR, func(p *Parser) (Statement, error) {
return p.parseSetPasswordUserStatement()
})
Language.Group(KILL).Handle(QUERY, func(p *Parser) (Statement, error) {
return p.parseKillQueryStatement()
})
}