Introduce build listeners and build report contributors.

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/IBuildListener.kt

@@ -0,0 +1,9 @@
+package com.beust.kobalt.api
+
+/**
+ * Plug-ins that listen to build events.
+ */
+interface IBuildListener : IListener {
+    fun taskStart(project: Project, context: KobaltContext, taskName: String)
+    fun taskEnd(project: Project, context: KobaltContext, taskName: String)
+}

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/IBuildReportContributor.kt

@@ -0,0 +1,8 @@
+package com.beust.kobalt.api
+
+/**
+ * Plug-ins that produce build reports.
+ */
+interface IBuildReportContributor : IContributor {
+    fun generateReport(context: KobaltContext)
+}

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/IPluginActor.kt

@@ -10,3 +10,6 @@ interface IPluginActor {
 interface IContributor : IPluginActor
 
 interface IInterceptor : IPluginActor
+
+interface IListener : IPluginActor
+

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/BuildListeners.kt

@@ -0,0 +1,39 @@
+package com.beust.kobalt.internal
+
+import com.beust.kobalt.Args
+import com.beust.kobalt.AsciiArt
+import com.beust.kobalt.api.*
+import com.beust.kobalt.misc.log
+import java.util.concurrent.ConcurrentHashMap
+
+/**
+ * Record timings and display them at the end of the build.
+ */
+class BuildListeners : IBuildListener, IBuildReportContributor {
+    class ProfilerInfo(val taskName: String, val durationMillis: Long)
+
+    private val startTimes = ConcurrentHashMap<String, Long>()
+    private val timings = arrayListOf<ProfilerInfo>()
+
+    override fun taskStart(project: Project, context: KobaltContext, taskName: String) {
+        startTimes.put(taskName, System.currentTimeMillis())
+    }
+
+    override fun taskEnd(project: Project, context: KobaltContext, taskName: String) {
+        startTimes[taskName]?.let {
+            timings.add(ProfilerInfo(taskName, System.currentTimeMillis() - it))
+        }
+    }
+
+    override fun generateReport(context: KobaltContext) {
+        val profiling = Kobalt.INJECTOR.getInstance(Args::class.java).profiling
+        if (profiling) {
+            log(1, "\n" + AsciiArt.horizontalSingleLine + " Timings (in seconds)")
+            timings.sortedByDescending { it.durationMillis }.forEach {
+                log(1, String.format("%1$10.2f", it.durationMillis.toDouble() / 1000)
+                        + " " + it.taskName)
+            }
+            log(1, "\n")
+        }
+    }
+}

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/KobaltPluginXml.kt

@@ -96,6 +96,8 @@ class PluginInfo(val xml: KobaltPluginXml, val pluginClassLoader: ClassLoader?,
     val mavenIdInterceptors = arrayListOf<IMavenIdInterceptor>()
     val jvmFlagContributors = arrayListOf<IJvmFlagContributor>()
     val localMavenRepoPathInterceptors = arrayListOf<ILocalMavenRepoPathInterceptor>()
+    val buildListeners = arrayListOf<IBuildListener>()
+    val buildReportContributors = arrayListOf<IBuildReportContributor>()
 
     // Note: intentionally repeating them here even though they are defined by our base class so
     // that this class always contains the full list of contributors and interceptors
@@ -212,6 +214,8 @@ class PluginInfo(val xml: KobaltPluginXml, val pluginClassLoader: ClassLoader?,
                 if (this is ITestJvmFlagInterceptor) testJvmFlagInterceptors.add(this)
                 if (this is IJvmFlagContributor) jvmFlagContributors.add(this)
                 if (this is ILocalMavenRepoPathInterceptor) localMavenRepoPathInterceptors.add(this)
+                if (this is IBuildListener) buildListeners.add(this)
+                if (this is IBuildReportContributor) buildReportContributors.add(this)
             }
         }
     }
@@ -225,7 +229,8 @@ class PluginInfo(val xml: KobaltPluginXml, val pluginClassLoader: ClassLoader?,
                 testSourceDirContributors, buildConfigFieldContributors,
                 taskContributors, incrementalTaskContributors, assemblyContributors,
                 incrementalAssemblyContributors, testJvmFlagInterceptors,
-                jvmFlagContributors, localMavenRepoPathInterceptors
+                jvmFlagContributors, localMavenRepoPathInterceptors, buildListeners,
+                buildReportContributors
             ).forEach {
                 it.forEach {
                     it.cleanUpActors()
@@ -266,6 +271,8 @@ class PluginInfo(val xml: KobaltPluginXml, val pluginClassLoader: ClassLoader?,
         testJvmFlagInterceptors.addAll(pluginInfo.testJvmFlagInterceptors)
         jvmFlagContributors.addAll(pluginInfo.jvmFlagContributors)
         localMavenRepoPathInterceptors.addAll(pluginInfo.localMavenRepoPathInterceptors)
+        buildListeners.addAll(pluginInfo.buildListeners)
+        buildReportContributors.addAll(pluginInfo.buildReportContributors)
     }
 }
 

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/TaskManager.kt

@@ -17,7 +17,8 @@ import javax.inject.Singleton
 
 @Singleton
 class TaskManager @Inject constructor(val args: Args,
-        val incrementalManagerFactory: IncrementalManager.IFactory) {
+        val incrementalManagerFactory: IncrementalManager.IFactory,
+        val pluginInfo: PluginInfo) {
     private val dependsOn = TreeMultimap.create<String, String>()
     private val reverseDependsOn = TreeMultimap.create<String, String>()
     private val runBefore = TreeMultimap.create<String, String>()
@@ -168,7 +169,7 @@ class TaskManager @Inject constructor(val args: Args,
 
                 val factory = object : IThreadWorkerFactory<ITask> {
                     override fun createWorkers(nodes: Collection<ITask>)
-                            = nodes.map { TaskWorker(listOf(it), args.dryRun, messages) }
+                            = nodes.map { TaskWorker(listOf(it), args.dryRun, messages, pluginInfo) }
                 }
 
                 val executor = DynamicGraphExecutor(graph, factory)
@@ -534,8 +535,13 @@ class TaskManager @Inject constructor(val args: Args,
     /////
 }
 
-class TaskWorker(val tasks: List<ITask>, val dryRun: Boolean, val timings: MutableList<TaskManager.ProfilerInfo>)
-        : IWorker<ITask> {
+class TaskWorker(val tasks: List<ITask>, val dryRun: Boolean, val pluginInfo: PluginInfo) : IWorker<ITask> {
+
+    private fun runBuildListeners(project: Project, context: KobaltContext, taskName: String, start: Boolean) {
+        context.pluginInfo.buildListeners.forEach {
+            if (start) it.taskStart(project, context, taskName) else it.taskEnd(project, context, taskName)
+        }
+    }
 
     override fun call() : TaskResult2<ITask> {
         if (tasks.size > 0) {
@@ -545,14 +551,14 @@ class TaskWorker(val tasks: List<ITask>, val dryRun: Boolean, val timings: Mutab
         }
         var success = true
         val errorMessages = arrayListOf<String>()
+        val context = Kobalt.context!!
         tasks.forEach {
             val name = it.project.name + ":" + it.name
-            val time = benchmarkMillis {
-                val tr = if (dryRun) TaskResult() else it.call()
-                success = success and tr.success
-                if (tr.errorMessage != null) errorMessages.add(tr.errorMessage)
-            }
-            timings.add(TaskManager.ProfilerInfo(name, time.first))
+            runBuildListeners(it.project, context, name, start = true)
+            val tr = if (dryRun) TaskResult() else it.call()
+            runBuildListeners(it.project, context, name, start = false)
+            success = success and tr.success
+            if (tr.errorMessage != null) errorMessages.add(tr.errorMessage)
         }
         return TaskResult2(success, errorMessages.joinToString("\n"), tasks[0])
     }