CodeGenScope.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
import androidx.room.writer.ClassWriter
import com.google.common.annotations.VisibleForTesting
import com.squareup.javapoet.CodeBlock
/**
* Defines a code generation scope where we can provide temporary variables, global variables etc
*/
class CodeGenScope(val writer: ClassWriter) {
private var tmpVarIndices = mutableMapOf<String, Int>()
private var builder: CodeBlock.Builder? = null
companion object {
const val TMP_VAR_DEFAULT_PREFIX = "_tmp"
const val CLASS_PROPERTY_PREFIX = "__"
@VisibleForTesting
fun _tmpVar(index: Int) = _tmpVar(TMP_VAR_DEFAULT_PREFIX, index)
fun _tmpVar(prefix: String, index: Int) = "$prefix${if (index == 0) "" else "_$index"}"
}
fun builder(): CodeBlock.Builder {
if (builder == null) {
builder = CodeBlock.builder()
}
return builder!!
}
fun getTmpVar(): String {
return getTmpVar(TMP_VAR_DEFAULT_PREFIX)
}
fun getTmpVar(prefix: String): String {
if (!prefix.startsWith("_")) {
throw IllegalArgumentException("tmp variable prefixes should start with _")
}
if (prefix.startsWith(CLASS_PROPERTY_PREFIX)) {
throw IllegalArgumentException("cannot use $CLASS_PROPERTY_PREFIX for tmp variables")
}
val index = tmpVarIndices.getOrElse(prefix) { 0 }
val result = _tmpVar(prefix, index)
tmpVarIndices.put(prefix, index + 1)
return result
}
fun generate(): CodeBlock = builder().build()
/**
* copies all variable indices but excludes generated code.
*/
fun fork(): CodeGenScope {
val forked = CodeGenScope(writer)
forked.tmpVarIndices.putAll(tmpVarIndices)
return forked
}
}