409 lines
11 KiB
Go
409 lines
11 KiB
Go
/*
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*
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* Query Generator Library
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* WIP Under Construction
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* Copyright Azareal 2017 - 2018
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*
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*/
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package qgen
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//import "fmt"
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import (
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"os"
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"strings"
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)
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func processColumns(colstr string) (columns []DBColumn) {
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if colstr == "" {
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return columns
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}
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colstr = strings.Replace(colstr, " as ", " AS ", -1)
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for _, segment := range strings.Split(colstr, ",") {
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var outcol DBColumn
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dotHalves := strings.Split(strings.TrimSpace(segment), ".")
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var halves []string
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if len(dotHalves) == 2 {
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outcol.Table = dotHalves[0]
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halves = strings.Split(dotHalves[1], " AS ")
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} else {
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halves = strings.Split(dotHalves[0], " AS ")
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}
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halves[0] = strings.TrimSpace(halves[0])
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if len(halves) == 2 {
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outcol.Alias = strings.TrimSpace(halves[1])
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}
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if halves[0][len(halves[0])-1] == ')' {
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outcol.Type = "function"
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} else if halves[0] == "?" {
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outcol.Type = "substitute"
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} else {
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outcol.Type = "column"
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}
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outcol.Left = halves[0]
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columns = append(columns, outcol)
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}
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return columns
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}
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// TODO: Allow order by statements without a direction
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func processOrderby(orderstr string) (order []DBOrder) {
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if orderstr == "" {
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return order
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}
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for _, segment := range strings.Split(orderstr, ",") {
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var outorder DBOrder
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halves := strings.Split(strings.TrimSpace(segment), " ")
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if len(halves) != 2 {
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continue
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}
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outorder.Column = halves[0]
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outorder.Order = strings.ToLower(halves[1])
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order = append(order, outorder)
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}
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return order
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}
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func processJoiner(joinstr string) (joiner []DBJoiner) {
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if joinstr == "" {
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return joiner
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}
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joinstr = strings.Replace(joinstr, " on ", " ON ", -1)
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joinstr = strings.Replace(joinstr, " and ", " AND ", -1)
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for _, segment := range strings.Split(joinstr, " AND ") {
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var outjoin DBJoiner
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var parseOffset int
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var left, right string
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left, parseOffset = getIdentifier(segment, parseOffset)
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outjoin.Operator, parseOffset = getOperator(segment, parseOffset+1)
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right, parseOffset = getIdentifier(segment, parseOffset+1)
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leftColumn := strings.Split(left, ".")
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rightColumn := strings.Split(right, ".")
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outjoin.LeftTable = strings.TrimSpace(leftColumn[0])
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outjoin.RightTable = strings.TrimSpace(rightColumn[0])
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outjoin.LeftColumn = strings.TrimSpace(leftColumn[1])
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outjoin.RightColumn = strings.TrimSpace(rightColumn[1])
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joiner = append(joiner, outjoin)
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}
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return joiner
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}
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func parseNumber(tmpWhere *DBWhere, segment string, i int) int {
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var buffer string
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for ; i < len(segment); i++ {
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char := segment[i]
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if '0' <= char && char <= '9' {
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buffer += string(char)
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} else {
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i--
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tmpWhere.Expr = append(tmpWhere.Expr, DBToken{buffer, "number"})
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return i
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}
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}
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return i
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}
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func parseColumn(tmpWhere *DBWhere, segment string, i int) int {
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var buffer string
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for ; i < len(segment); i++ {
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char := segment[i]
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if ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '.' || char == '_' {
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buffer += string(char)
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} else if char == '(' {
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return parseFunction(tmpWhere, segment, buffer, i)
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} else {
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i--
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tmpWhere.Expr = append(tmpWhere.Expr, DBToken{buffer, "column"})
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return i
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}
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}
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return i
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}
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func parseFunction(tmpWhere *DBWhere, segment string, buffer string, i int) int {
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var preI = i
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i = skipFunctionCall(segment, i-1)
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buffer += segment[preI:i] + string(segment[i])
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tmpWhere.Expr = append(tmpWhere.Expr, DBToken{buffer, "function"})
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return i
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}
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func processWhere(wherestr string) (where []DBWhere) {
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if wherestr == "" {
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return where
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}
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wherestr = strings.Replace(wherestr, " and ", " AND ", -1)
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var buffer string
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var optype int // 0: None, 1: Number, 2: Column, 3: Function, 4: String, 5: Operator
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for _, segment := range strings.Split(wherestr, " AND ") {
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var tmpWhere = &DBWhere{[]DBToken{}}
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segment += ")"
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for i := 0; i < len(segment); i++ {
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char := segment[i]
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switch optype {
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case 0: // unknown
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if '0' <= char && char <= '9' {
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i = parseNumber(tmpWhere, segment, i)
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} else if ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '_' {
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i = parseColumn(tmpWhere, segment, i)
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} else if char == '\'' {
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optype = 4
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buffer = ""
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} else if isOpByte(char) {
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optype = 5
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buffer = string(char)
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} else if char == '?' {
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tmpWhere.Expr = append(tmpWhere.Expr, DBToken{"?", "substitute"})
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}
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case 4: // string
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if char != '\'' {
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buffer += string(char)
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} else {
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optype = 0
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tmpWhere.Expr = append(tmpWhere.Expr, DBToken{buffer, "string"})
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}
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case 5: // operator
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if isOpByte(char) {
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buffer += string(char)
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} else {
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optype = 0
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i--
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tmpWhere.Expr = append(tmpWhere.Expr, DBToken{buffer, "operator"})
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}
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default:
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panic("Bad optype in processWhere")
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}
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}
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where = append(where, *tmpWhere)
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}
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return where
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}
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func processSet(setstr string) (setter []DBSetter) {
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if setstr == "" {
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return setter
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}
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// First pass, splitting the string by commas while ignoring the innards of functions
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var setset []string
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var buffer string
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var lastItem int
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setstr += ","
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for i := 0; i < len(setstr); i++ {
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if setstr[i] == '(' {
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i = skipFunctionCall(setstr, i-1)
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setset = append(setset, setstr[lastItem:i+1])
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buffer = ""
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lastItem = i + 2
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} else if setstr[i] == ',' && buffer != "" {
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setset = append(setset, buffer)
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buffer = ""
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lastItem = i + 1
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} else if (setstr[i] > 32) && setstr[i] != ',' && setstr[i] != ')' {
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buffer += string(setstr[i])
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}
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}
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// Second pass. Break this setitem into manageable chunks
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buffer = ""
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for _, setitem := range setset {
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var tmpSetter DBSetter
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halves := strings.Split(setitem, "=")
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if len(halves) != 2 {
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continue
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}
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tmpSetter.Column = strings.TrimSpace(halves[0])
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segment := halves[1] + ")"
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var optype int // 0: None, 1: Number, 2: Column, 3: Function, 4: String, 5: Operator
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//fmt.Println("segment", segment)
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for i := 0; i < len(segment); i++ {
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char := segment[i]
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//fmt.Println("optype",optype)
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//fmt.Println("Expr:",buffer)
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switch optype {
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case 0: // unknown
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if '0' <= char && char <= '9' {
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optype = 1
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buffer = string(char)
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} else if ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '_' {
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optype = 2
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buffer = string(char)
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} else if char == '\'' {
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optype = 4
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buffer = ""
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} else if isOpByte(char) {
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optype = 5
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buffer = string(char)
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} else if char == '?' {
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tmpSetter.Expr = append(tmpSetter.Expr, DBToken{"?", "substitute"})
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}
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case 1: // number
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if '0' <= char && char <= '9' {
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buffer += string(char)
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} else {
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optype = 0
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i--
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tmpSetter.Expr = append(tmpSetter.Expr, DBToken{buffer, "number"})
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}
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case 2: // column
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if ('a' <= char && char <= 'z') || ('A' <= char && char <= 'Z') || char == '_' {
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buffer += string(char)
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} else if char == '(' {
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optype = 3
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i--
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} else {
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optype = 0
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i--
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tmpSetter.Expr = append(tmpSetter.Expr, DBToken{buffer, "column"})
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}
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case 3: // function
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var preI = i
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i = skipFunctionCall(segment, i-1)
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buffer += segment[preI:i] + string(segment[i])
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tmpSetter.Expr = append(tmpSetter.Expr, DBToken{buffer, "function"})
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optype = 0
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case 4: // string
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if char != '\'' {
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buffer += string(char)
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} else {
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optype = 0
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tmpSetter.Expr = append(tmpSetter.Expr, DBToken{buffer, "string"})
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}
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case 5: // operator
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if isOpByte(char) {
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buffer += string(char)
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} else {
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optype = 0
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i--
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tmpSetter.Expr = append(tmpSetter.Expr, DBToken{buffer, "operator"})
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}
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default:
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panic("Bad optype in processSet")
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}
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}
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setter = append(setter, tmpSetter)
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}
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return setter
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}
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func processLimit(limitstr string) (limiter DBLimit) {
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halves := strings.Split(limitstr, ",")
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if len(halves) == 2 {
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limiter.Offset = halves[0]
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limiter.MaxCount = halves[1]
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} else {
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limiter.MaxCount = halves[0]
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}
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return limiter
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}
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func isOpByte(char byte) bool {
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return char == '<' || char == '>' || char == '=' || char == '!' || char == '*' || char == '%' || char == '+' || char == '-' || char == '/'
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}
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func isOpRune(char rune) bool {
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return char == '<' || char == '>' || char == '=' || char == '!' || char == '*' || char == '%' || char == '+' || char == '-' || char == '/'
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}
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func processFields(fieldstr string) (fields []DBField) {
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if fieldstr == "" {
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return fields
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}
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var buffer string
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var lastItem int
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fieldstr += ","
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for i := 0; i < len(fieldstr); i++ {
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if fieldstr[i] == '(' {
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i = skipFunctionCall(fieldstr, i-1)
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fields = append(fields, DBField{Name: fieldstr[lastItem : i+1], Type: getIdentifierType(fieldstr[lastItem : i+1])})
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buffer = ""
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lastItem = i + 2
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} else if fieldstr[i] == ',' && buffer != "" {
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fields = append(fields, DBField{Name: buffer, Type: getIdentifierType(buffer)})
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buffer = ""
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lastItem = i + 1
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} else if (fieldstr[i] > 32) && fieldstr[i] != ',' && fieldstr[i] != ')' {
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buffer += string(fieldstr[i])
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}
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}
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return fields
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}
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func getIdentifierType(identifier string) string {
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if ('a' <= identifier[0] && identifier[0] <= 'z') || ('A' <= identifier[0] && identifier[0] <= 'Z') {
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if identifier[len(identifier)-1] == ')' {
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return "function"
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}
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return "column"
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}
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if identifier[0] == '\'' || identifier[0] == '"' {
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return "string"
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}
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return "literal"
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}
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func getIdentifier(segment string, startOffset int) (out string, i int) {
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segment = strings.TrimSpace(segment)
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segment += " " // Avoid overflow bugs with slicing
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for i = startOffset; i < len(segment); i++ {
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if segment[i] == '(' {
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i = skipFunctionCall(segment, i)
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return strings.TrimSpace(segment[startOffset:i]), (i - 1)
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}
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if (segment[i] == ' ' || isOpByte(segment[i])) && i != startOffset {
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return strings.TrimSpace(segment[startOffset:i]), (i - 1)
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}
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}
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return strings.TrimSpace(segment[startOffset:]), (i - 1)
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}
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func getOperator(segment string, startOffset int) (out string, i int) {
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segment = strings.TrimSpace(segment)
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segment += " " // Avoid overflow bugs with slicing
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for i = startOffset; i < len(segment); i++ {
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if !isOpByte(segment[i]) && i != startOffset {
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return strings.TrimSpace(segment[startOffset:i]), (i - 1)
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}
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}
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return strings.TrimSpace(segment[startOffset:]), (i - 1)
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}
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func skipFunctionCall(data string, index int) int {
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var braceCount int
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for ; index < len(data); index++ {
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char := data[index]
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if char == '(' {
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braceCount++
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} else if char == ')' {
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braceCount--
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if braceCount == 0 {
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return index
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}
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}
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}
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return index
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}
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func writeFile(name string, content string) (err error) {
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f, err := os.Create(name)
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if err != nil {
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return err
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}
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_, err = f.WriteString(content)
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if err != nil {
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return err
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}
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err = f.Sync()
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if err != nil {
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return err
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}
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return f.Close()
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}
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