surrealpatch/sql/exprs.go
2016-11-22 19:10:42 +00:00

842 lines
16 KiB
Go

// Copyright © 2016 Abcum Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package sql
import (
"fmt"
"regexp"
"time"
"golang.org/x/crypto/bcrypt"
"github.com/abcum/surreal/util/rand"
)
func (p *parser) parseWhat() (mul []Expr, err error) {
for {
tok, lit, err := p.shouldBe(IDENT, NUMBER, DOUBLE, THING, PARAM)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"table name or record id"}}
}
if p.is(tok, IDENT, NUMBER, DOUBLE) {
one, _ := p.declare(TABLE, lit)
mul = append(mul, one)
}
if p.is(tok, THING) {
one, _ := p.declare(THING, lit)
mul = append(mul, one)
}
if p.is(tok, PARAM) {
one, _ := p.declare(PARAM, lit)
mul = append(mul, one)
}
// Check to see if the next token is a comma
// and if not, then break out of the loop,
// otherwise repeat until we find no comma.
if _, _, exi := p.mightBe(COMMA); !exi {
break
}
}
return
}
func (p *parser) parseName() (string, error) {
_, lit, err := p.shouldBe(IDENT, STRING, NUMBER, DOUBLE)
if err != nil {
return string(""), &ParseError{Found: lit, Expected: []string{"name"}}
}
val, err := p.declare(STRING, lit)
return val.(string), err
}
func (p *parser) parseNames() (mul []string, err error) {
for {
one, err := p.parseName()
if err != nil {
return nil, err
}
mul = append(mul, one)
// Check to see if the next token is a comma
// and if not, then break out of the loop,
// otherwise repeat until we find no comma.
if _, _, exi := p.mightBe(COMMA); !exi {
break
}
}
return
}
// --------------------------------------------------
//
// --------------------------------------------------
func (p *parser) parseCond() (exp Expr, err error) {
// The next token that we expect to see is a
// WHERE token, and if we don't find one then
// return nil, with no error.
if _, _, exi := p.mightBe(WHERE); !exi {
return nil, nil
}
return p.parseExpr()
}
// --------------------------------------------------
//
// --------------------------------------------------
func (p *parser) parseRand() (exp []byte, err error) {
exp = rand.New(128)
return
}
// --------------------------------------------------
//
// --------------------------------------------------
func (p *parser) parseIdent() (*Ident, error) {
_, lit, err := p.shouldBe(IDENT)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"name"}}
}
val, err := p.declare(IDENT, lit)
return val.(*Ident), err
}
func (p *parser) parseTable() (*Table, error) {
_, lit, err := p.shouldBe(IDENT, NUMBER, DOUBLE)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"name"}}
}
val, err := p.declare(TABLE, lit)
return val.(*Table), err
}
func (p *parser) parseThing() (*Thing, error) {
_, lit, err := p.shouldBe(THING)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"record id"}}
}
val, err := p.declare(THING, lit)
return val.(*Thing), err
}
func (p *parser) parseArray() ([]interface{}, error) {
_, lit, err := p.shouldBe(ARRAY)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"array"}}
}
val, err := p.declare(ARRAY, lit)
return val.([]interface{}), err
}
func (p *parser) parseObject() (exp map[string]interface{}, err error) {
_, lit, err := p.shouldBe(JSON)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"object"}}
}
val, err := p.declare(JSON, lit)
return val.(map[string]interface{}), err
}
func (p *parser) parseNumber() (int64, error) {
_, lit, err := p.shouldBe(NUMBER)
if err != nil {
return int64(0), &ParseError{Found: lit, Expected: []string{"number"}}
}
val, err := p.declare(NUMBER, lit)
return val.(int64), err
}
func (p *parser) parseDouble() (float64, error) {
_, lit, err := p.shouldBe(NUMBER, DOUBLE)
if err != nil {
return float64(0), &ParseError{Found: lit, Expected: []string{"number"}}
}
val, err := p.declare(DOUBLE, lit)
return val.(float64), err
}
func (p *parser) parseString() (string, error) {
_, lit, err := p.shouldBe(STRING)
if err != nil {
return string(""), &ParseError{Found: lit, Expected: []string{"string"}}
}
val, err := p.declare(STRING, lit)
return val.(string), err
}
func (p *parser) parseRegion() (string, error) {
tok, lit, err := p.shouldBe(STRING, REGION)
if err != nil {
return string(""), &ParseError{Found: lit, Expected: []string{"string"}}
}
val, err := p.declare(tok, lit)
return val.(string), err
}
func (p *parser) parseBinary() ([]byte, error) {
tok, lit, err := p.shouldBe(STRING, REGION)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"string"}}
}
val, err := p.declare(tok, lit)
return []byte(val.(string)), err
}
func (p *parser) parseScript() (string, error) {
tok, lit, err := p.shouldBe(STRING, REGION)
if err != nil {
return string(""), &ParseError{Found: lit, Expected: []string{"js/lua script"}}
}
val, err := p.declare(tok, lit)
return val.(string), err
}
func (p *parser) parseRegexp() (string, error) {
tok, lit, err := p.shouldBe(REGEX)
if err != nil {
return string(""), &ParseError{Found: lit, Expected: []string{"regular expression"}}
}
val, err := p.declare(tok, lit)
return val.(*regexp.Regexp).String(), err
}
func (p *parser) parseBoolean() (bool, error) {
tok, lit, err := p.shouldBe(TRUE, FALSE)
if err != nil {
return bool(false), &ParseError{Found: lit, Expected: []string{"boolean"}}
}
val, err := p.declare(tok, lit)
return val.(bool), err
}
func (p *parser) parseDuration() (time.Duration, error) {
tok, lit, err := p.shouldBe(DURATION)
if err != nil {
return 0, &ParseError{Found: lit, Expected: []string{"duration"}}
}
val, err := p.declare(tok, lit)
return val.(time.Duration), err
}
func (p *parser) parseBcrypt() ([]byte, error) {
_, lit, err := p.shouldBe(STRING)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"string"}}
}
val, err := p.declare(STRING, lit)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"string"}}
}
return bcrypt.GenerateFromPassword([]byte(val.(string)), bcrypt.DefaultCost)
}
func (p *parser) parseAlgorithm() (string, error) {
expected := []string{
"ES256", "ES384", "ES512",
"HS256", "HS384", "HS512",
"PS256", "PS384", "PS512",
"RS256", "RS384", "RS512",
}
_, lit, err := p.shouldBe(IDENT, STRING)
if err != nil {
return string(""), &ParseError{Found: lit, Expected: expected}
}
switch lit {
case "ES256", "ES384", "ES512":
case "HS256", "HS384", "HS512":
case "PS256", "PS384", "PS512":
case "RS256", "RS384", "RS512":
default:
return string(""), &ParseError{Found: lit, Expected: expected}
}
val, err := p.declare(STRING, lit)
return val.(string), err
}
func (p *parser) parseExpr() (exp Expr, err error) {
// Create the root binary expression tree.
root := &BinaryExpression{}
// If the subsequent token is an in, out, or
// multi way path expression, then parse all
// following expressions as a path.
if tok, _, exi := p.mightBe(OEDGE, IEDGE, BEDGE); exi {
return p.parsePath(tok)
}
// Begin with parsing the first expression
// as the root of the tree to start with.
root.RHS, err = p.parsePart()
if err != nil {
return nil, err
}
// If the subsequent token is an in, out, or
// multi way path expression, then parse all
// following expressions as a path.
if tok, _, exi := p.mightBe(OEDGE, IEDGE, BEDGE); exi {
return p.parsePath(root.RHS, tok)
}
// Loop over the operations and expressions
// and build a binary expression tree based
// on the precedence of the operators.
for {
var rhs Expr
// Get the next token from the scanner and
// the literal value that it is scanned as.
tok, lit, _ := p.scan()
switch tok {
// If the token is an AND or OR expression
// then skip to the next expression without
// further checks.
case AND, OR:
// If the token is not an operator but can
// be converted into an operator based on
// logic, then convert it to an operator.
case IN:
tok = INS
if _, _, exi := p.mightBe(NOT); exi {
tok = NIS
}
case CONTAINS:
tok = SIN
if _, _, exi := p.mightBe(NOT); exi {
tok = SNI
}
case IS:
tok = EQ
if _, _, exi := p.mightBe(NOT); exi {
tok = NEQ
}
if _, _, exi := p.mightBe(IN); exi {
switch tok {
case EQ:
tok = INS
case NEQ:
tok = NIS
}
}
// If the token is a keyword which is also
// actually an operator, then skip to the
// next expression without further checks.
case CONTAINSALL, CONTAINSNONE, CONTAINSSOME:
case ALLCONTAINEDIN, NONECONTAINEDIN, SOMECONTAINEDIN:
// If the token is an int64 or a float64 then
// check to see whether the first rune is a
// + or a - and use it as a token instead.
case NUMBER, DOUBLE:
switch lit[0] {
case '-':
rhs, err = p.declare(tok, lit[1:])
tok = SUB
case '+':
rhs, err = p.declare(tok, lit[1:])
tok = ADD
default:
p.unscan()
return root.RHS, nil
}
// Check to see if the token is an operator
// expression. If it is none of those then
// unscan and break out of the loop.
default:
if !tok.isOperator() {
p.unscan()
return root.RHS, nil
}
}
// If the token was not an int64 or float64
// signed value then retrieve the next part
// of the expression and add it to the right.
if rhs == nil {
rhs, err = p.parsePart()
if err != nil {
return nil, err
}
}
// Find the right place in the tree to add the
// new expression, by descending the right side
// of the tree until we reach the last binary
// expression, or until we reach an expression
// whose operator precendence >= this precedence.
for node := root; ; {
r, ok := node.RHS.(*BinaryExpression)
if !ok || r.Op.precedence() >= tok.precedence() {
node.RHS = &BinaryExpression{LHS: node.RHS, Op: tok, RHS: rhs}
break
}
node = r
}
}
return root, err
}
func (p *parser) parsePart() (exp Expr, err error) {
toks := []Token{
MUL, ID, IDENT, THING,
NULL, VOID, EMPTY, MISSING,
TRUE, FALSE, STRING, REGION, NUMBER, DOUBLE,
NOW, DATE, TIME, DURATION, JSON, ARRAY, PARAM, LPAREN,
}
tok, lit, _ := p.scan()
// We need to declare the type up here instead
// of at the bottom, as the held value might
// be overwritten by the next token scan.
exp, err = p.declare(tok, lit)
if err != nil {
return nil, err
}
// If the current token is a left parenthesis
// bracket, then we will parse this complete
// expression part as a subquery.
if p.is(tok, LPAREN) {
return p.parseSubq()
}
// If the next token is a left parenthesis
// bracket, then we will parse this complete
// expression part as a function call.
if _, _, exi := p.mightBe(LPAREN); exi {
return p.parseCall(lit)
}
// If this expression is not a subquery or a
// function call, then check to see if the
// token is in the list of allowed tokens.
if !p.in(tok, toks) {
err = &ParseError{Found: lit, Expected: []string{"expression"}}
}
return
}
func (p *parser) parseSubq() (sub *SubExpression, err error) {
var exp Expr
var tok Token
tok, _, _ = p.mightBe(SELECT, CREATE, UPDATE, DELETE, RELATE)
switch tok {
default:
exp, err = p.parseExpr()
case SELECT:
exp, err = p.parseSelectStatement()
case CREATE:
exp, err = p.parseCreateStatement()
case UPDATE:
exp, err = p.parseUpdateStatement()
case DELETE:
exp, err = p.parseDeleteStatement()
case RELATE:
exp, err = p.parseRelateStatement()
}
p.mightBe(RPAREN)
return &SubExpression{Expr: exp}, err
}
func (p *parser) parseCall(name string) (fnc *FuncExpression, err error) {
fnc = &FuncExpression{Name: name}
// Check to see if the immediate token
// is a right parenthesis bracket, and if
// it is then this function has no args.
if _, _, exi := p.mightBe(RPAREN); !exi {
for {
var arg Expr
arg, err = p.parseExpr()
if err != nil {
return nil, err
}
// Append the single expression to the array
// of function argument expressions.
fnc.Args = append(fnc.Args, arg)
// Check to see if the next token is a comma
// and if not, then break out of the loop,
// otherwise repeat until we find no comma.
if _, _, exi := p.mightBe(COMMA); !exi {
break
}
}
_, _, err = p.shouldBe(RPAREN)
}
// Check to see if the used function name is
// valid according to the currently supported
// functions. If not then return an error.
if _, ok := funcs[fnc.Name]; !ok {
return nil, &ParseError{
Found: fmt.Sprintf("%s()", name),
Expected: []string{"valid function name"},
}
}
// Check to see if the number of arguments
// is correct for the specified function name,
// and if not, then return an error.
if _, ok := funcs[fnc.Name][len(fnc.Args)]; !ok {
s, t := "", len(funcs[fnc.Name])
for i := 0; i < t; i++ {
switch {
case i > 0 && i == t-1:
s = s + " or "
case i > 0:
s = s + ", "
}
s = s + fmt.Sprintf("%d", i)
}
switch {
case t == 1:
s = s + " argument"
case t >= 2:
s = s + " arguments"
}
return nil, &ParseError{
Found: fmt.Sprintf("%s() with %d arguments", fnc.Name, len(fnc.Args)),
Expected: []string{s},
}
}
return
}
func (p *parser) parsePath(expr ...Expr) (path *PathExpression, err error) {
path = &PathExpression{}
// Take the previosuly scanned expression
// and append it to the path expression
// tree as the first item.
for _, e := range expr {
switch v := e.(type) {
case Token:
path.Expr = append(path.Expr, &JoinExpression{Join: v})
default:
path.Expr = append(path.Expr, &PartExpression{Part: v})
}
}
// If the last expression passed in was a
// path joiner (->, <-, or <->), then we
// need to process a path part first.
if _, ok := expr[len(expr)-1].(Token); ok {
var part Expr
part, err = p.parseStep()
if err != nil {
return nil, err
}
if part == nil {
return
}
path.Expr = append(path.Expr, &PartExpression{Part: part})
}
for {
var join Expr
var part Expr
// We expect the next token to be a join
// operator (->, <-, or <->), otherwise we
// are at the end of the path and will
// ignore it and return.
join, err = p.parseJoin()
if err != nil {
return nil, err
}
if join == nil {
return
}
path.Expr = append(path.Expr, &JoinExpression{Join: join.(Token)})
// We expect the next token to be a path
// part identifier, otherwise we are at
// the end of the path and will ignore it
// and return.
part, err = p.parseStep()
if err != nil {
return nil, err
}
if part == nil {
return
}
path.Expr = append(path.Expr, &PartExpression{Part: part})
}
return
}
func (p *parser) parseJoin() (exp Expr, err error) {
toks := []Token{
OEDGE, IEDGE, BEDGE,
}
tok, _, _ := p.scan()
if !p.in(tok, toks) {
p.unscan()
return
}
return tok, err
}
func (p *parser) parseStep() (exp Expr, err error) {
toks := []Token{
QMARK, IDENT, THING, PARAM, LPAREN,
}
tok, lit, _ := p.scan()
// We need to declare the type up here instead
// of at the bottom, as the held value might
// be overwritten by the next token scan.
exp, err = p.declare(tok, lit)
if err != nil {
return nil, err
}
// If the current token is a left parenthesis
// bracket, then we will parse this complete
// expression part as a subquery.
if p.is(tok, LPAREN) {
return p.parseSubp()
}
// If this expression is not a sub-path
// expression, then check to see if the
// token is in the list of allowed tokens.
if !p.in(tok, toks) {
p.unscan()
exp = nil
}
return
}
func (p *parser) parseSubp() (stmt *SubpExpression, err error) {
stmt = &SubpExpression{}
if stmt.What, err = p.parseWhat(); err != nil {
return nil, err
}
if _, _, exi := p.mightBe(AS); exi {
if stmt.Name, err = p.parseName(); err != nil {
return nil, err
}
}
if stmt.Cond, err = p.parseCond(); err != nil {
return nil, err
}
if _, _, err = p.shouldBe(RPAREN); err != nil {
return nil, err
}
return
}