1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package androidx.room.solver
18 
19 import androidx.room.writer.ClassWriter
20 import com.google.common.annotations.VisibleForTesting
21 import com.squareup.javapoet.CodeBlock
22 
23 /**
24  * Defines a code generation scope where we can provide temporary variables, global variables etc
25  */
26 class CodeGenScope(val writer: ClassWriter) {
27     private var tmpVarIndices = mutableMapOf<String, Int>()
28     private var builder: CodeBlock.Builder? = null
29     companion object {
30         const val TMP_VAR_DEFAULT_PREFIX = "_tmp"
31         const val CLASS_PROPERTY_PREFIX = "__"
32         @VisibleForTesting
_tmpVarnull33         fun _tmpVar(index: Int) = _tmpVar(TMP_VAR_DEFAULT_PREFIX, index)
34         fun _tmpVar(prefix: String, index: Int) = "$prefix${if (index == 0) "" else "_$index"}"
35     }
36 
37     fun builder(): CodeBlock.Builder {
38         if (builder == null) {
39             builder = CodeBlock.builder()
40         }
41         return builder!!
42     }
43 
getTmpVarnull44     fun getTmpVar(): String {
45         return getTmpVar(TMP_VAR_DEFAULT_PREFIX)
46     }
47 
getTmpVarnull48     fun getTmpVar(prefix: String): String {
49         if (!prefix.startsWith("_")) {
50             throw IllegalArgumentException("tmp variable prefixes should start with _")
51         }
52         if (prefix.startsWith(CLASS_PROPERTY_PREFIX)) {
53             throw IllegalArgumentException("cannot use $CLASS_PROPERTY_PREFIX for tmp variables")
54         }
55         val index = tmpVarIndices.getOrElse(prefix) { 0 }
56         val result = _tmpVar(prefix, index)
57         tmpVarIndices.put(prefix, index + 1)
58         return result
59     }
60 
generatenull61     fun generate() = builder().build().toString()
62 
63     /**
64      * copies all variable indices but excludes generated code.
65      */
66     fun fork(): CodeGenScope {
67         val forked = CodeGenScope(writer)
68         forked.tmpVarIndices.putAll(tmpVarIndices)
69         return forked
70     }
71 }
72