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// SPDX-License-Identifier: BSD-3-Clause
package org.islandoftex.arara.model
import org.islandoftex.arara.Arara
import org.islandoftex.arara.configuration.AraraSpec
import org.islandoftex.arara.localization.LanguageController
import org.islandoftex.arara.localization.Messages
import org.islandoftex.arara.ruleset.Conditional
import org.islandoftex.arara.utils.Methods
import org.mvel2.templates.TemplateRuntime
/**
* Implements the evaluator model, on which a conditional can be analyzed and
* processed.
*
* @author Island of TeX
* @version 5.0
* @since 4.0
*/
class Evaluator {
// this attribute holds the maximum number of
// loops arara will accept; it's like
// reaching infinity
private val loops: Int = Arara.config[AraraSpec.Execution.maxLoops]
// the counter for the current execution, it
// helps us keep track of the number of times
// this evaluation has happened, and also to
// prevent potential infinite loops
private var counter: Int = 0
// a flag that indicates the
// evaluation to halt regardless
// of the the result
private var halt: Boolean = false
/**
* Check if a condition is of type if or unless and whether halt
* is set.
* @param type The type to check.
* @param haltCheck The value [halt] should have.
* @return `(type == if || type == unless) && haltCheck`
*/
private fun isIfUnlessAndHalt(
type: Conditional.ConditionalType,
haltCheck: Boolean = true
): Boolean =
(type == Conditional.ConditionalType.IF ||
type == Conditional.ConditionalType.UNLESS) &&
halt == haltCheck
/**
* Only run the evaluation of the conditional including a check whether
* the result needs to be inverted.
* @param conditional The conditional.
* @return The result of the evaluation.
*/
@Throws(AraraException::class, RuntimeException::class)
private fun evaluateCondition(conditional: Conditional): Boolean {
val result = TemplateRuntime.eval("@{ " + conditional.condition + " }",
Methods.getConditionalMethods())
return if (result is Boolean) {
if (conditional.type == Conditional.ConditionalType.UNLESS ||
conditional.type == Conditional.ConditionalType.UNTIL)
!result
else
result
} else {
throw AraraException(messages.getMessage(
Messages.ERROR_EVALUATE_NOT_BOOLEAN_VALUE))
}
}
/**
* Evaluate the provided conditional.
*
* @param conditional The conditional object.
* @return A boolean value indicating if the conditional holds.
* @throws AraraException Something wrong happened, to be caught in the
* higher levels.
*/
@Throws(AraraException::class)
@Suppress("TooGenericExceptionCaught")
fun evaluate(conditional: Conditional): Boolean {
// when in dry-run mode or not evaluating a
// conditional, arara always ignores conditional
// evaluations
if (conditional.type == Conditional.ConditionalType.NONE ||
Arara.config[AraraSpec.Execution.dryrun] ||
isIfUnlessAndHalt(conditional.type, true))
return false
else if (isIfUnlessAndHalt(conditional.type, false)) {
halt = true
}
// check counters and see if the execution
// has reached our concept of infinity,
// thus breaking the cycles
counter++
return when {
conditional.type === Conditional.ConditionalType.WHILE
&& counter > loops -> false
conditional.type === Conditional.ConditionalType.UNTIL
&& counter >= loops -> false
else -> {
try {
evaluateCondition(conditional)
} catch (exception: RuntimeException) {
throw AraraException(messages.getMessage(Messages
.ERROR_EVALUATE_COMPILATION_FAILED),
exception)
}
}
}
}
companion object {
// the application messages obtained from the
// language controller
private val messages = LanguageController
}
}
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