io.sentry.android.gradle.instrumentation.AbstractSpanAddingMethodVisitor.kt Maven / Gradle / Ivy

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package io.sentry.android.gradle.instrumentation

import io.sentry.android.gradle.instrumentation.util.Types
import java.util.concurrent.atomic.AtomicBoolean
import kotlin.properties.Delegates
import org.objectweb.asm.Label
import org.objectweb.asm.MethodVisitor
import org.objectweb.asm.Opcodes
import org.objectweb.asm.Type
import org.objectweb.asm.commons.LocalVariablesSorter

/**
 * Base class for all [MethodVisitor] that inject spans bytecode into existing methods. Abstracts
 * away most of the logic like creating a span, setting span status, finishing a span, etc.
 *
 * Since it inherits from [LocalVariablesSorter] for introducing new local variables, all child classes
 * **must** use [originalVisitor] for all visiting operations, otherwise all variables visits will be always remapped,
 * even those that we don't want to.
 */
abstract class AbstractSpanAddingMethodVisitor(
    api: Int,
    originalVisitor: MethodVisitor,
    access: Int,
    descriptor: String?
) : LocalVariablesSorter(api, access, descriptor, originalVisitor) {

    protected val instrumenting = AtomicBoolean(false)
    protected var childIndex by Delegates.notNull()

    protected val label0 = Label()
    protected val label1 = Label()
    protected val label2 = Label()
    protected val label3 = Label()
    protected val label4 = Label()

    // bytecode preparations for try-catch blocks
    protected open fun MethodVisitor.visitTryCatchBlocks(expectedException: String) {
        visitTryCatchBlock(label0, label1, label2, expectedException)
        visitTryCatchBlock(label0, label1, label3, null)
        visitTryCatchBlock(label2, label4, label3, null)
    }

    /*
    ISpan span = Sentry.getSpan()
    ISpan child = null;
    if (span != null) {
      child = span.startChild("db", );
    }
    */
    protected fun MethodVisitor.visitStartSpan(
        gotoIfNull: Label,
        descriptionVisitor: MethodVisitor.() -> Unit
    ) {
        visitMethodInsn(
            Opcodes.INVOKESTATIC,
            "io/sentry/Sentry",
            "getSpan",
            "()Lio/sentry/ISpan;",
            /* isInterface = */ false
        )
        val spanIndex = newLocal(Types.SPAN)
        childIndex = newLocal(Types.SPAN)
        visitVarInsn(Opcodes.ASTORE, spanIndex) // span
        visitInsn(Opcodes.ACONST_NULL)
        visitVarInsn(Opcodes.ASTORE, childIndex) // child
        visitVarInsn(Opcodes.ALOAD, spanIndex) // span
        visitJumpInsn(Opcodes.IFNULL, gotoIfNull)
        visitVarInsn(Opcodes.ALOAD, spanIndex) // span
        descriptionVisitor()
        visitMethodInsn(
            Opcodes.INVOKEINTERFACE,
            "io/sentry/ISpan",
            "startChild",
            "(Ljava/lang/String;Ljava/lang/String;)Lio/sentry/ISpan;",
            /* isInterface = */ true
        )
        visitVarInsn(Opcodes.ASTORE, childIndex) // child = ...
    }

    /*
    if (child != null) {
      child.setStatus(SpanStatus.OK|SpanStatus.INTERNAL_ERROR);
    }
     */
    protected fun MethodVisitor.visitSetStatus(status: String, gotoIfNull: Label) {
        visitVarInsn(Opcodes.ALOAD, childIndex) // child
        visitJumpInsn(Opcodes.IFNULL, gotoIfNull)
        visitVarInsn(Opcodes.ALOAD, childIndex)
        visitFieldInsn(
            Opcodes.GETSTATIC,
            "io/sentry/SpanStatus",
            status,
            "Lio/sentry/SpanStatus;"
        )
        visitMethodInsn(
            Opcodes.INVOKEINTERFACE,
            "io/sentry/ISpan",
            "setStatus",
            "(Lio/sentry/SpanStatus;)V",
            /* isInterface = */true
        )
    }

    /*
    child.setThrowable(e);
     */
    private fun MethodVisitor.visitSetThrowable(varToLoad: Int) {
        visitVarInsn(Opcodes.ALOAD, childIndex) // child

        visitVarInsn(Opcodes.ALOAD, varToLoad) // Exception e
        visitMethodInsn(
            Opcodes.INVOKEINTERFACE,
            "io/sentry/ISpan",
            "setThrowable",
            "(Ljava/lang/Throwable;)V",
            /* isInterface = */true
        )
    }

    /*
    finally {
       if (child != null) {
         child.finish();
       }
     }
     */
    protected fun MethodVisitor.visitFinallyBlock(gotoIfNull: Label, status: String? = null) {
        visitVarInsn(Opcodes.ALOAD, childIndex)
        visitJumpInsn(Opcodes.IFNULL, gotoIfNull)
        visitVarInsn(Opcodes.ALOAD, childIndex)
        if (status != null) {
            visitFieldInsn(
                Opcodes.GETSTATIC,
                "io/sentry/SpanStatus",
                status,
                "Lio/sentry/SpanStatus;"
            )
        }
        visitMethodInsn(
            Opcodes.INVOKEINTERFACE,
            "io/sentry/ISpan",
            "finish",
            if (status == null) "()V" else "(Lio/sentry/SpanStatus;)V",
            /* isInterface = */true
        )
    }

    /*
    catch (Exception e) {
      if (child != null) {
        child.setStatus(SpanStatus.INTERNAL_ERROR);
        child.setThrowable(e);
      }
      throw e;
     }
     */
    protected fun MethodVisitor.visitCatchBlock(
        catchLabel: Label,
        throwLabel: Label,
        exceptionType: Type = Types.EXCEPTION
    ) {
        val exceptionIndex = newLocal(exceptionType)
        visitLabel(catchLabel)
        visitVarInsn(Opcodes.ASTORE, exceptionIndex) // Exception e
        visitSetStatus(status = "INTERNAL_ERROR", gotoIfNull = throwLabel)
        visitSetThrowable(varToLoad = exceptionIndex)

        visitLabel(throwLabel)
        visitThrow(varToLoad = exceptionIndex)
    }

    /*
    throw e;
     */
    protected fun MethodVisitor.visitThrow(varToLoad: Int) {
        visitVarInsn(Opcodes.ALOAD, varToLoad) // Exception e
        visitInsn(Opcodes.ATHROW)
    }
}