TypeConverter.kt
/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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 androidx.room.solver.types
import androidx.room.compiler.processing.XType
import androidx.room.ext.L
import androidx.room.ext.T
import androidx.room.solver.CodeGenScope
/**
* A code generator that can convert from 1 type to another
*/
abstract class TypeConverter(val from: XType, val to: XType) {
/**
* Should generate the code that will covert [inputVarName] of type [from] to [outputVarName]
* of type [to]. This method *should not* declare the [outputVarName] as it is already
* declared by the caller.
*/
protected abstract fun doConvert(
inputVarName: String,
outputVarName: String,
scope: CodeGenScope
)
/**
* A type converter can optionally override this method if they can handle the case where
* they don't need a temporary output variable (e.g. no op conversion or null checks).
*
* @return The variable name where the result is saved.
*/
protected open fun doConvert(
inputVarName: String,
scope: CodeGenScope
): String {
val outVarName = scope.getTmpVar()
scope.builder().apply {
addStatement("final $T $L", to.typeName, outVarName)
}
doConvert(
inputVarName = inputVarName,
outputVarName = outVarName,
scope = scope
)
return outVarName
}
fun convert(
inputVarName: String,
scope: CodeGenScope
): String = doConvert(inputVarName, scope)
fun convert(
inputVarName: String,
outputVarName: String,
scope: CodeGenScope
) {
doConvert(inputVarName, outputVarName, scope)
}
}