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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.spark.sql.catalyst.parser
import scala.collection.mutable.StringBuilder
import org.antlr.v4.runtime.{CharStream, ParserRuleContext, Token}
import org.antlr.v4.runtime.misc.Interval
import org.antlr.v4.runtime.tree.TerminalNode
import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan
import org.apache.spark.sql.catalyst.trees.{CurrentOrigin, Origin}
/**
* A collection of utility methods for use during the parsing process.
*/
object ParserUtils {
/** Get the command which created the token. */
def command(ctx: ParserRuleContext): String = {
command(ctx.getStart.getInputStream)
}
/** Get the command which created the token. */
def command(stream: CharStream): String = {
stream.getText(Interval.of(0, stream.size()))
}
/** Get the code that creates the given node. */
def source(ctx: ParserRuleContext): String = {
val stream = ctx.getStart.getInputStream
stream.getText(Interval.of(ctx.getStart.getStartIndex, ctx.getStop.getStopIndex))
}
/** Get all the text which comes after the given rule. */
def remainder(ctx: ParserRuleContext): String = remainder(ctx.getStop)
/** Get all the text which comes after the given token. */
def remainder(token: Token): String = {
val stream = token.getInputStream
val interval = Interval.of(token.getStopIndex + 1, stream.size())
stream.getText(interval)
}
/** Convert a string token into a string. */
def string(token: Token): String = unescapeSQLString(token.getText)
/** Convert a string node into a string. */
def string(node: TerminalNode): String = unescapeSQLString(node.getText)
/** Get the origin (line and position) of the token. */
def position(token: Token): Origin = {
Origin(Option(token.getLine), Option(token.getCharPositionInLine))
}
/** Assert if a condition holds. If it doesn't throw a parse exception. */
def assert(f: => Boolean, message: String, ctx: ParserRuleContext): Unit = {
if (!f) {
throw new ParseException(message, ctx)
}
}
/**
* Register the origin of the context. Any TreeNode created in the closure will be assigned the
* registered origin. This method restores the previously set origin after completion of the
* closure.
*/
def withOrigin[T](ctx: ParserRuleContext)(f: => T): T = {
val current = CurrentOrigin.get
CurrentOrigin.set(position(ctx.getStart))
try {
f
} finally {
CurrentOrigin.set(current)
}
}
/** Unescape baskslash-escaped string enclosed by quotes. */
def unescapeSQLString(b: String): String = {
var enclosure: Character = null
val sb = new StringBuilder(b.length())
def appendEscapedChar(n: Char) {
n match {
case '0' => sb.append('\u0000')
case '\'' => sb.append('\'')
case '"' => sb.append('\"')
case 'b' => sb.append('\b')
case 'n' => sb.append('\n')
case 'r' => sb.append('\r')
case 't' => sb.append('\t')
case 'Z' => sb.append('\u001A')
case '\\' => sb.append('\\')
// The following 2 lines are exactly what MySQL does TODO: why do we do this?
case '%' => sb.append("\\%")
case '_' => sb.append("\\_")
case _ => sb.append(n)
}
}
var i = 0
val strLength = b.length
while (i < strLength) {
val currentChar = b.charAt(i)
if (enclosure == null) {
if (currentChar == '\'' || currentChar == '\"') {
enclosure = currentChar
}
} else if (enclosure == currentChar) {
enclosure = null
} else if (currentChar == '\\') {
if ((i + 6 < strLength) && b.charAt(i + 1) == 'u') {
// \u0000 style character literals.
val base = i + 2
val code = (0 until 4).foldLeft(0) { (mid, j) =>
val digit = Character.digit(b.charAt(j + base), 16)
(mid << 4) + digit
}
sb.append(code.asInstanceOf[Char])
i += 5
} else if (i + 4 < strLength) {
// \000 style character literals.
val i1 = b.charAt(i + 1)
val i2 = b.charAt(i + 2)
val i3 = b.charAt(i + 3)
if ((i1 >= '0' && i1 <= '1') && (i2 >= '0' && i2 <= '7') && (i3 >= '0' && i3 <= '7')) {
val tmp = ((i3 - '0') + ((i2 - '0') << 3) + ((i1 - '0') << 6)).asInstanceOf[Char]
sb.append(tmp)
i += 3
} else {
appendEscapedChar(i1)
i += 1
}
} else if (i + 2 < strLength) {
// escaped character literals.
val n = b.charAt(i + 1)
appendEscapedChar(n)
i += 1
}
} else {
// non-escaped character literals.
sb.append(currentChar)
}
i += 1
}
sb.toString()
}
/** Some syntactic sugar which makes it easier to work with optional clauses for LogicalPlans. */
implicit class EnhancedLogicalPlan(val plan: LogicalPlan) extends AnyVal {
/**
* Create a plan using the block of code when the given context exists. Otherwise return the
* original plan.
*/
def optional(ctx: AnyRef)(f: => LogicalPlan): LogicalPlan = {
if (ctx != null) {
f
} else {
plan
}
}
/**
* Map a [[LogicalPlan]] to another [[LogicalPlan]] if the passed context exists using the
* passed function. The original plan is returned when the context does not exist.
*/
def optionalMap[C <: ParserRuleContext](
ctx: C)(
f: (C, LogicalPlan) => LogicalPlan): LogicalPlan = {
if (ctx != null) {
f(ctx, plan)
} else {
plan
}
}
}
}
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