Refactor Api extensions

src/main/kotlin/com/gabrielfeo/gradle/enterprise/api/GradleEnterpriseApiExtensions.kt

@@ -1,14 +1,15 @@
 package com.gabrielfeo.gradle.enterprise.api
 
+import com.gabrielfeo.gradle.enterprise.api.internal.API_MAX_BUILDS
+import com.gabrielfeo.gradle.enterprise.api.internal.operator.pagedUntilLastBuild
+import com.gabrielfeo.gradle.enterprise.api.internal.operator.withGradleAttributes
 import com.gabrielfeo.gradle.enterprise.api.model.*
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.DelicateCoroutinesApi
 import kotlinx.coroutines.GlobalScope
-import kotlinx.coroutines.async
 import kotlinx.coroutines.flow.*
 import retrofit2.await
 
-private const val API_MAX_BUILDS = 1000
-
 /**
  * Gets builds on demand from the API, in as many requests as necessary. It allows
  * for queries of any size, as opposed to [GradleEnterpriseApi.getBuilds] which is limited by the
@@ -24,43 +25,17 @@ fun GradleEnterpriseApi.getBuildsFlow(
     fromInstant: Long? = null,
     fromBuild: String? = null,
 ): Flow<Build> = flow {
-    var lastBuildId: String? = null
-    while (true) {
-        val call = when (lastBuildId) {
-            null -> getBuilds(
-                since = since, sinceBuild = sinceBuild,
-                fromInstant = fromInstant, fromBuild = fromBuild,
-                maxBuilds = API_MAX_BUILDS,
-            )
-            else -> getBuilds(fromBuild = lastBuildId, maxBuilds = API_MAX_BUILDS)
-        }
-        val builds = call.await()
-        emitAll(builds.asFlow())
-        when {
-            builds.isEmpty() || builds.size < API_MAX_BUILDS -> break
-            else -> lastBuildId = builds.last().id
-        }
-    }
+    val firstBuilds = getBuilds(
+        since = since,
+        sinceBuild = sinceBuild,
+        fromInstant = fromInstant,
+        fromBuild = fromBuild,
+        maxBuilds = API_MAX_BUILDS,
+    ).await()
+    val pagedBuilds = firstBuilds.asFlow().pagedUntilLastBuild(maxPerRequest = API_MAX_BUILDS)
+    emitAll(pagedBuilds)
 }
 
-/**
- * Joins builds with their [GradleAttributes], which comes from a different endpoint
- * ([GradleEnterpriseApi.getGradleAttributes]).
- *
- * Don't expect client-side filtering to be efficient. Does as many concurrent calls
- * as it can, requesting attributes in an eager coroutine, in [scope].
- */
-fun Flow<Build>.withGradleAttributes(
-    scope: CoroutineScope = GlobalScope,
-): Flow<Pair<Build, GradleAttributes>> =
-    map { build ->
-        build to scope.async {
-            api.getGradleAttributes(build.id).await()
-        }
-    }.buffer(Int.MAX_VALUE).map { (build, attrs) ->
-        build to attrs.await()
-    }
-
 /**
  * Gets [GradleAttributes] of all builds from a given date. Queries [GradleEnterpriseApi.getBuilds]
  * first, since it's the only endpoint providing a timeline of builds, then maps each to
@@ -69,7 +44,10 @@ fun Flow<Build>.withGradleAttributes(
  * Don't expect client-side filtering to be efficient. Does as many concurrent calls
  * as it can, requesting attributes in an eager coroutine, in [scope]. For other params,
  * see [getBuildsFlow] and [GradleEnterpriseApi.getBuilds].
+ *
+ * @param scope CoroutineScope in which to create coroutines. Defaults to [GlobalScope].
  */
+@OptIn(DelicateCoroutinesApi::class)
 fun GradleEnterpriseApi.getGradleAttributesFlow(
     since: Long = 0,
     sinceBuild: String? = null,

src/main/kotlin/com/gabrielfeo/gradle/enterprise/api/internal/ApiConstants.kt

@@ -0,0 +1,8 @@
+package com.gabrielfeo.gradle.enterprise.api.internal
+
+import com.gabrielfeo.gradle.enterprise.api.GradleEnterpriseApi
+
+/**
+ * Undocumented max value of `/api/builds?maxBuilds`. Last checked in 2022.4.
+ */
+internal const val API_MAX_BUILDS = 1000

src/main/kotlin/com/gabrielfeo/gradle/enterprise/api/internal/operator/pagedUntilLastBuild.kt

@@ -0,0 +1,34 @@
+package com.gabrielfeo.gradle.enterprise.api.internal.operator
+
+import com.gabrielfeo.gradle.enterprise.api.*
+import com.gabrielfeo.gradle.enterprise.api.internal.API_MAX_BUILDS
+import com.gabrielfeo.gradle.enterprise.api.model.*
+import kotlinx.coroutines.flow.*
+import retrofit2.await
+
+/**
+ * Emits all available builds starting from the upstream Flow builds until the last build available.
+ * Makes paged requests to the API using `fromBuild`, [maxPerRequest] at a time.
+ */
+internal fun Flow<Build>.pagedUntilLastBuild(
+    maxPerRequest: Int,
+): Flow<Build> {
+    val firstBuilds = this
+    return flow {
+        var lastBuildId = ""
+        firstBuilds.collect {
+            lastBuildId = it.id
+            emit(it)
+        }
+        if (lastBuildId.isEmpty()) {
+            return@flow
+        } else while (true) {
+            val builds = api.getBuilds(fromBuild = lastBuildId, maxBuilds = maxPerRequest).await()
+            emitAll(builds.asFlow())
+            when {
+                builds.isEmpty() || builds.size < API_MAX_BUILDS -> break
+                else -> lastBuildId = builds.last().id
+            }
+        }
+    }
+}

src/main/kotlin/com/gabrielfeo/gradle/enterprise/api/internal/operator/withGradleAttributes.kt

@@ -0,0 +1,25 @@
+package com.gabrielfeo.gradle.enterprise.api.internal.operator
+
+import com.gabrielfeo.gradle.enterprise.api.*
+import com.gabrielfeo.gradle.enterprise.api.model.*
+import kotlinx.coroutines.*
+import kotlinx.coroutines.flow.*
+import retrofit2.await
+
+/**
+ * Joins builds with their [GradleAttributes], which comes from a different endpoint
+ * ([GradleEnterpriseApi.getGradleAttributes]).
+ *
+ * Don't expect client-side filtering to be efficient. Does as many concurrent calls
+ * as it can, requesting attributes in an eager coroutine, in [scope].
+ */
+internal fun Flow<Build>.withGradleAttributes(
+    scope: CoroutineScope,
+): Flow<Pair<Build, GradleAttributes>> =
+    map { build ->
+        build to scope.async {
+            api.getGradleAttributes(build.id).await()
+        }
+    }.buffer(Int.MAX_VALUE).map { (build, attrs) ->
+        build to attrs.await()
+    }