gosora/query_gen/lib/utils.go

451 lines
12 KiB
Go

/*
*
* Query Generator Library
* WIP Under Construction
* Copyright Azareal 2017 - 2018
*
*/
package qgen
//import "fmt"
import (
"os"
"strings"
)
func processColumns(colstr string) (columns []DBColumn) {
if colstr == "" {
return columns
}
colstr = strings.Replace(colstr, " as ", " AS ", -1)
for _, segment := range strings.Split(colstr, ",") {
var outcol DBColumn
dotHalves := strings.Split(strings.TrimSpace(segment), ".")
var halves []string
if len(dotHalves) == 2 {
outcol.Table = dotHalves[0]
halves = strings.Split(dotHalves[1], " AS ")
} else {
halves = strings.Split(dotHalves[0], " AS ")
}
halves[0] = strings.TrimSpace(halves[0])
if len(halves) == 2 {
outcol.Alias = strings.TrimSpace(halves[1])
}
if halves[0][len(halves[0])-1] == ')' {
outcol.Type = "function"
} else if halves[0] == "?" {
outcol.Type = "substitute"
} else {
outcol.Type = "column"
}
outcol.Left = halves[0]
columns = append(columns, outcol)
}
return columns
}
// TODO: Allow order by statements without a direction
func processOrderby(orderstr string) (order []DBOrder) {
if orderstr == "" {
return order
}
for _, segment := range strings.Split(orderstr, ",") {
var outorder DBOrder
halves := strings.Split(strings.TrimSpace(segment), " ")
if len(halves) != 2 {
continue
}
outorder.Column = halves[0]
outorder.Order = strings.ToLower(halves[1])
order = append(order, outorder)
}
return order
}
func processJoiner(joinstr string) (joiner []DBJoiner) {
if joinstr == "" {
return joiner
}
joinstr = strings.Replace(joinstr, " on ", " ON ", -1)
joinstr = strings.Replace(joinstr, " and ", " AND ", -1)
for _, segment := range strings.Split(joinstr, " AND ") {
var outjoin DBJoiner
var parseOffset int
var left, right string
left, parseOffset = getIdentifier(segment, parseOffset)
outjoin.Operator, parseOffset = getOperator(segment, parseOffset+1)
right, parseOffset = getIdentifier(segment, parseOffset+1)
leftColumn := strings.Split(left, ".")
rightColumn := strings.Split(right, ".")
outjoin.LeftTable = strings.TrimSpace(leftColumn[0])
outjoin.RightTable = strings.TrimSpace(rightColumn[0])
outjoin.LeftColumn = strings.TrimSpace(leftColumn[1])
outjoin.RightColumn = strings.TrimSpace(rightColumn[1])
joiner = append(joiner, outjoin)
}
return joiner
}
func (where *DBWhere) parseNumber(segment string, i int) int {
var buffer string
for ; i < len(segment); i++ {
char := segment[i]
if '0' <= char && char <= '9' {
buffer += string(char)
} else {
i--
where.Expr = append(where.Expr, DBToken{buffer, "number"})
return i
}
}
return i
}
func (where *DBWhere) parseColumn(segment string, i int) int {
var buffer string
for ; i < len(segment); i++ {
char := segment[i]
switch {
case ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '.' || char == '_':
buffer += string(char)
case char == '(':
return where.parseFunction(segment, buffer, i)
default:
i--
where.Expr = append(where.Expr, DBToken{buffer, "column"})
return i
}
}
return i
}
func (where *DBWhere) parseFunction(segment string, buffer string, i int) int {
var preI = i
i = skipFunctionCall(segment, i-1)
buffer += segment[preI:i] + string(segment[i])
where.Expr = append(where.Expr, DBToken{buffer, "function"})
return i
}
func (where *DBWhere) parseString(segment string, i int) int {
var buffer string
i++
for ; i < len(segment); i++ {
char := segment[i]
if char != '\'' {
buffer += string(char)
} else {
where.Expr = append(where.Expr, DBToken{buffer, "string"})
return i
}
}
return i
}
func (where *DBWhere) parseOperator(segment string, i int) int {
var buffer string
for ; i < len(segment); i++ {
char := segment[i]
if isOpByte(char) {
buffer += string(char)
} else {
i--
where.Expr = append(where.Expr, DBToken{buffer, "operator"})
return i
}
}
return i
}
// TODO: Make this case insensitive
func normalizeAnd(in string) string {
in = strings.Replace(in, " and ", " AND ", -1)
return strings.Replace(in, " && ", " AND ", -1)
}
func normalizeOr(in string) string {
in = strings.Replace(in, " or ", " OR ", -1)
return strings.Replace(in, " || ", " OR ", -1)
}
// TODO: Write tests for this
func processWhere(wherestr string) (where []DBWhere) {
if wherestr == "" {
return where
}
wherestr = normalizeAnd(wherestr)
wherestr = normalizeOr(wherestr)
for _, segment := range strings.Split(wherestr, " AND ") {
var tmpWhere = &DBWhere{[]DBToken{}}
segment += ")"
for i := 0; i < len(segment); i++ {
char := segment[i]
switch {
case '0' <= char && char <= '9':
i = tmpWhere.parseNumber(segment, i)
// TODO: Sniff the third byte offset from char or it's non-existent to avoid matching uppercase strings which start with OR
case char == 'O' && (i+1) < len(segment) && segment[i+1] == 'R':
tmpWhere.Expr = append(tmpWhere.Expr, DBToken{"OR", "or"})
i += 1
case ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '_':
i = tmpWhere.parseColumn(segment, i)
case char == '\'':
i = tmpWhere.parseString(segment, i)
case char == ')' && i < (len(segment)-1):
tmpWhere.Expr = append(tmpWhere.Expr, DBToken{")", "operator"})
case isOpByte(char):
i = tmpWhere.parseOperator(segment, i)
case char == '?':
tmpWhere.Expr = append(tmpWhere.Expr, DBToken{"?", "substitute"})
}
}
where = append(where, *tmpWhere)
}
return where
}
func (setter *DBSetter) parseNumber(segment string, i int) int {
var buffer string
for ; i < len(segment); i++ {
char := segment[i]
if '0' <= char && char <= '9' {
buffer += string(char)
} else {
setter.Expr = append(setter.Expr, DBToken{buffer, "number"})
return i
}
}
return i
}
func (setter *DBSetter) parseColumn(segment string, i int) int {
var buffer string
for ; i < len(segment); i++ {
char := segment[i]
switch {
case ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '_':
buffer += string(char)
case char == '(':
return setter.parseFunction(segment, buffer, i)
default:
i--
setter.Expr = append(setter.Expr, DBToken{buffer, "column"})
return i
}
}
return i
}
func (setter *DBSetter) parseFunction(segment string, buffer string, i int) int {
var preI = i
i = skipFunctionCall(segment, i-1)
buffer += segment[preI:i] + string(segment[i])
setter.Expr = append(setter.Expr, DBToken{buffer, "function"})
return i
}
func (setter *DBSetter) parseString(segment string, i int) int {
var buffer string
i++
for ; i < len(segment); i++ {
char := segment[i]
if char != '\'' {
buffer += string(char)
} else {
setter.Expr = append(setter.Expr, DBToken{buffer, "string"})
return i
}
}
return i
}
func (setter *DBSetter) parseOperator(segment string, i int) int {
var buffer string
for ; i < len(segment); i++ {
char := segment[i]
if isOpByte(char) {
buffer += string(char)
} else {
i--
setter.Expr = append(setter.Expr, DBToken{buffer, "operator"})
return i
}
}
return i
}
func processSet(setstr string) (setter []DBSetter) {
if setstr == "" {
return setter
}
// First pass, splitting the string by commas while ignoring the innards of functions
var setset []string
var buffer string
var lastItem int
setstr += ","
for i := 0; i < len(setstr); i++ {
if setstr[i] == '(' {
i = skipFunctionCall(setstr, i-1)
setset = append(setset, setstr[lastItem:i+1])
buffer = ""
lastItem = i + 2
} else if setstr[i] == ',' && buffer != "" {
setset = append(setset, buffer)
buffer = ""
lastItem = i + 1
} else if (setstr[i] > 32) && setstr[i] != ',' && setstr[i] != ')' {
buffer += string(setstr[i])
}
}
// Second pass. Break this setitem into manageable chunks
for _, setitem := range setset {
halves := strings.Split(setitem, "=")
if len(halves) != 2 {
continue
}
tmpSetter := &DBSetter{Column: strings.TrimSpace(halves[0])}
segment := halves[1] + ")"
for i := 0; i < len(segment); i++ {
char := segment[i]
switch {
case '0' <= char && char <= '9':
i = tmpSetter.parseNumber(segment, i)
case ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '_':
i = tmpSetter.parseColumn(segment, i)
case char == '\'':
i = tmpSetter.parseString(segment, i)
case isOpByte(char):
i = tmpSetter.parseOperator(segment, i)
case char == '?':
tmpSetter.Expr = append(tmpSetter.Expr, DBToken{"?", "substitute"})
}
}
setter = append(setter, *tmpSetter)
}
return setter
}
func processLimit(limitstr string) (limiter DBLimit) {
halves := strings.Split(limitstr, ",")
if len(halves) == 2 {
limiter.Offset = halves[0]
limiter.MaxCount = halves[1]
} else {
limiter.MaxCount = halves[0]
}
return limiter
}
func isOpByte(char byte) bool {
return char == '<' || char == '>' || char == '=' || char == '!' || char == '*' || char == '%' || char == '+' || char == '-' || char == '/' || char == '(' || char == ')'
}
func isOpRune(char rune) bool {
return char == '<' || char == '>' || char == '=' || char == '!' || char == '*' || char == '%' || char == '+' || char == '-' || char == '/' || char == '(' || char == ')'
}
func processFields(fieldstr string) (fields []DBField) {
if fieldstr == "" {
return fields
}
var buffer string
var lastItem int
fieldstr += ","
for i := 0; i < len(fieldstr); i++ {
if fieldstr[i] == '(' {
i = skipFunctionCall(fieldstr, i-1)
fields = append(fields, DBField{Name: fieldstr[lastItem : i+1], Type: getIdentifierType(fieldstr[lastItem : i+1])})
buffer = ""
lastItem = i + 2
} else if fieldstr[i] == ',' && buffer != "" {
fields = append(fields, DBField{Name: buffer, Type: getIdentifierType(buffer)})
buffer = ""
lastItem = i + 1
} else if (fieldstr[i] > 32) && fieldstr[i] != ',' && fieldstr[i] != ')' {
buffer += string(fieldstr[i])
}
}
return fields
}
func getIdentifierType(identifier string) string {
if ('a' <= identifier[0] && identifier[0] <= 'z') || ('A' <= identifier[0] && identifier[0] <= 'Z') {
if identifier[len(identifier)-1] == ')' {
return "function"
}
return "column"
}
if identifier[0] == '\'' || identifier[0] == '"' {
return "string"
}
return "literal"
}
func getIdentifier(segment string, startOffset int) (out string, i int) {
segment = strings.TrimSpace(segment)
segment += " " // Avoid overflow bugs with slicing
for i = startOffset; i < len(segment); i++ {
if segment[i] == '(' {
i = skipFunctionCall(segment, i)
return strings.TrimSpace(segment[startOffset:i]), (i - 1)
}
if (segment[i] == ' ' || isOpByte(segment[i])) && i != startOffset {
return strings.TrimSpace(segment[startOffset:i]), (i - 1)
}
}
return strings.TrimSpace(segment[startOffset:]), (i - 1)
}
func getOperator(segment string, startOffset int) (out string, i int) {
segment = strings.TrimSpace(segment)
segment += " " // Avoid overflow bugs with slicing
for i = startOffset; i < len(segment); i++ {
if !isOpByte(segment[i]) && i != startOffset {
return strings.TrimSpace(segment[startOffset:i]), (i - 1)
}
}
return strings.TrimSpace(segment[startOffset:]), (i - 1)
}
func skipFunctionCall(data string, index int) int {
var braceCount int
for ; index < len(data); index++ {
char := data[index]
if char == '(' {
braceCount++
} else if char == ')' {
braceCount--
if braceCount == 0 {
return index
}
}
}
return index
}
func writeFile(name string, content string) (err error) {
f, err := os.Create(name)
if err != nil {
return err
}
_, err = f.WriteString(content)
if err != nil {
return err
}
err = f.Sync()
if err != nil {
return err
}
return f.Close()
}