lava-oushudb-dt-sql-parser/lib/filter.js

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2018-07-02 18:01:01 +08:00
const replaceStrFormIndexArr=require("../utils").replaceStrFormIndexArr;
function filterComments(sql) {
let tmpArr = [];
const comments = [];
for (let i = 0; i < sql.length; i++) {
let char = sql[i];
//读取字符
if (char == "'" || char == "\"" || char == "-" || char == "\n") {
//推入数组
tmpArr.push({
index: i,
char: char
});
}
//校验数组是否有匹配语法
if (tmpArr.length < 2) {
if (tmpArr[0] && tmpArr[0].char == "\n") {
tmpArr = [];
}
continue;
}
let firstChar = tmpArr[0];
let lastChar = tmpArr[tmpArr.length - 1];
if (firstChar.char == "'" || firstChar.char == "\"") {
//引号匹配,则清空
if (lastChar.char == firstChar.char) {
tmpArr = [];
continue;
}
} else if (firstChar.char == "-") {
//假如第一个是横线,则开始校验注释规则
//判断是否为两个注释符号,不是,则清空
if (tmpArr[1].char != "-") {
tmpArr = [];
continue;
}
//为注释作用域,遇到换行符,则结束注释
else if (lastChar.char == "\n") {
comments.push({
begin: firstChar.index,
end: lastChar.index
})
tmpArr = [];
continue;
}
//解析结束
else if (i == sql.length - 1) {
comments.push({
begin: firstChar.index,
end: i
})
continue;
}
} else {
tmpArr = [];
}
}
sql = replaceStrFormIndexArr(sql, '', comments)
return sql;
}
function cleanSql(sql){
return filterComments(sql).trim();
}
exports.filterComments=filterComments;
exports.cleanSql=cleanSql;