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      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 android.databinding.tool.expr
     18 
     19 import android.databinding.tool.reflection.Callable
     20 import android.databinding.tool.solver.ExecutionPath
     21 import android.databinding.tool.writer.KCode
     22 import android.databinding.tool.writer.fieldName
     23 import android.databinding.tool.writer.isForcedToLocalize
     24 import android.databinding.tool.writer.isVariable
     25 import android.databinding.tool.writer.kcode
     26 import android.databinding.tool.writer.scopedName
     27 
     28 fun Expr.shouldLocalizeInCallbacks() = canBeEvaluatedToAVariable() && !resolvedType.isVoid && (isDynamic || isForcedToLocalize())
     29 
     30 fun CallbackExprModel.localizeGlobalVariables(vararg ignore: Expr): KCode = kcode("// localize variables for thread safety") {
     31     // puts all variables in this model to local values.
     32     mExprMap.values.filter { it.shouldLocalizeInCallbacks() && !ignore.contains(it) }.forEach {
     33         nl("// ${it.toString()}")
     34         nl("${it.resolvedType.toJavaCode()} ${it.scopedName()} = ${if (it.isVariable()) it.fieldName else it.defaultValue};")
     35     }
     36 }
     37 
     38 fun ExecutionPath.toCode(): KCode = kcode("") {
     39     val myExpr = expr
     40     if (myExpr != null && !isAlreadyEvaluated) {
     41         // variables are read up top
     42         val localize = myExpr.shouldLocalizeInCallbacks() && !myExpr.isVariable()
     43         // if this is not a method call (or method call via field access, don't do anything
     44         val eligible = localize || (myExpr is MethodCallExpr || (myExpr is FieldAccessExpr && myExpr.getter.type == Callable.Type.METHOD))
     45         if (eligible) {
     46             val assign = if (localize) {
     47                 "${myExpr.scopedName()} = "
     48             } else {
     49                 ""
     50             }
     51             if (myExpr is TernaryExpr) {
     52                 // if i know the value, short circuit it
     53                 if (knownValues.containsKey(myExpr.pred)) {
     54                     val chosen = if (knownValues[myExpr.pred]!!) myExpr.ifTrue else myExpr.ifFalse
     55                     // fast read me
     56                     nl("$assign${chosen.toCode().generate()};")
     57                 } else {
     58                     // read me
     59                     nl("$assign${myExpr.toFullCode().generate()};")
     60                 }
     61             } else {
     62                 // read me
     63                 nl("$assign${myExpr.toFullCode().generate()};")
     64             }
     65         }
     66     }
     67     children.forEach {
     68         nl(it.toCode())
     69     }
     70     // if i have branches, execute them
     71     val myTrue = trueBranch
     72     val myFalse = falseBranch
     73     if (myTrue != null) {
     74         val condition = with(myTrue.conditional) {
     75             if (shouldLocalizeInCallbacks()) {
     76                 scopedName()
     77             } else {
     78                 toFullCode().generate()
     79             }
     80         }
     81         block("if ($condition)") {
     82             nl(myTrue.path.toCode())
     83         }
     84         if (myFalse != null) {
     85             block("else") {
     86                 nl(myFalse.path.toCode())
     87             }
     88         }
     89     }
     90 }