Improve stream rendering performances

benchmarks/src/main/scala/fs2/data/benchmarks/PrinterBenchmarks.scala

@@ -0,0 +1,85 @@
+package fs2.data.benchmarks
+
+import cats.effect.SyncIO
+import cats.effect.IO
+import fs2.data.json.Token
+import fs2.data.json.circe.*
+import fs2.{Fallible, Stream}
+import io.circe.Json
+import org.openjdk.jmh.annotations.*
+import org.openjdk.jmh.infra.Blackhole
+import cats.effect.unsafe.implicits.global
+
+import java.util.concurrent.TimeUnit
+
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@BenchmarkMode(Array(Mode.AverageTime))
+@State(org.openjdk.jmh.annotations.Scope.Benchmark)
+@Fork(value = 1)
+@Warmup(iterations = 15, time = 5)
+@Measurement(iterations = 10, time = 5)
+class PrinterBenchmarks {
+
+  val intArrayStream =
+    Stream.emits(
+      Token.StartArray ::
+        (List
+          .range(0, 1000000)
+          .map(i => Token.NumberValue(i.toString())) :+ Token.EndArray))
+
+  val objectStream =
+    Stream.emits(
+      Token.StartObject ::
+        (List
+          .range(0, 1000000)
+          .flatMap(i => List(Token.Key(s"key:$i"), Token.NumberValue(i.toString()))) :+ Token.EndObject))
+
+  @Benchmark
+  def intArrayCompact(bh: Blackhole) =
+    bh.consume(
+      intArrayStream
+        .through(fs2.data.json.render.compact)
+        .compile
+        .drain)
+
+  @Benchmark
+  def objectCompact(bh: Blackhole) =
+    bh.consume(
+      objectStream
+        .through(fs2.data.json.render.compact)
+        .compile
+        .drain)
+
+  @Benchmark
+  def intArrayPretty(bh: Blackhole) =
+    bh.consume(
+      intArrayStream
+        .through(fs2.data.json.render.prettyPrint())
+        .compile
+        .drain)
+
+  @Benchmark
+  def objectPretty(bh: Blackhole) =
+    bh.consume(
+      objectStream
+        .through(fs2.data.json.render.prettyPrint())
+        .compile
+        .drain)
+
+  @Benchmark
+  def intArrayPrettyLegacy(bh: Blackhole) =
+    bh.consume(
+      intArrayStream
+        .through(fs2.data.json.render.pretty())
+        .compile
+        .drain)
+
+  @Benchmark
+  def objectPrettyLegacy(bh: Blackhole) =
+    bh.consume(
+      objectStream
+        .through(fs2.data.json.render.pretty())
+        .compile
+        .drain)
+
+}

build.sbt

@@ -142,7 +142,46 @@ lazy val text = crossProject(JVMPlatform, JSPlatform, NativePlatform)
       ProblemFilters.exclude[IncompatibleMethTypeProblem]("fs2.data.text.CharLikeStringChunks.pullNext"),
       ProblemFilters.exclude[IncompatibleMethTypeProblem]("fs2.data.text.CharLikeStringChunks.advance"),
       ProblemFilters.exclude[IncompatibleMethTypeProblem]("fs2.data.text.CharLikeStringChunks.current"),
-      ProblemFilters.exclude[MissingClassProblem]("fs2.data.text.CharLikeStringChunks$StringContext")
+      ProblemFilters.exclude[MissingClassProblem]("fs2.data.text.CharLikeStringChunks$StringContext"),
+      ProblemFilters.exclude[MissingClassProblem]("fs2.data.text.render.internal.Annotated$AlignBegin"),
+      ProblemFilters.exclude[MissingTypesProblem]("fs2.data.text.render.internal.Annotated$AlignBegin$"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#AlignBegin.apply"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#AlignBegin.unapply"),
+      ProblemFilters.exclude[IncompatibleResultTypeProblem](
+        "fs2.data.text.render.internal.Annotated#AlignBegin.fromProduct"),
+      ProblemFilters.exclude[MissingClassProblem]("fs2.data.text.render.internal.Annotated$AlignEnd"),
+      ProblemFilters.exclude[MissingTypesProblem]("fs2.data.text.render.internal.Annotated$AlignEnd$"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#AlignEnd.apply"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#AlignEnd.unapply"),
+      ProblemFilters.exclude[IncompatibleResultTypeProblem](
+        "fs2.data.text.render.internal.Annotated#AlignEnd.fromProduct"),
+      ProblemFilters.exclude[MissingClassProblem]("fs2.data.text.render.internal.Annotated$GroupEnd"),
+      ProblemFilters.exclude[MissingTypesProblem]("fs2.data.text.render.internal.Annotated$GroupEnd$"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#GroupEnd.apply"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#GroupEnd.unapply"),
+      ProblemFilters.exclude[IncompatibleResultTypeProblem](
+        "fs2.data.text.render.internal.Annotated#GroupEnd.fromProduct"),
+      ProblemFilters.exclude[MissingClassProblem]("fs2.data.text.render.internal.Annotated$IndentBegin"),
+      ProblemFilters.exclude[MissingTypesProblem]("fs2.data.text.render.internal.Annotated$IndentBegin$"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#IndentBegin.apply"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#IndentBegin.unapply"),
+      ProblemFilters.exclude[IncompatibleResultTypeProblem](
+        "fs2.data.text.render.internal.Annotated#IndentBegin.fromProduct"),
+      ProblemFilters.exclude[MissingClassProblem]("fs2.data.text.render.internal.Annotated$IndentEnd"),
+      ProblemFilters.exclude[MissingTypesProblem]("fs2.data.text.render.internal.Annotated$IndentEnd$"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#IndentEnd.apply"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#IndentEnd.unapply"),
+      ProblemFilters.exclude[IncompatibleResultTypeProblem](
+        "fs2.data.text.render.internal.Annotated#IndentEnd.fromProduct"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#Line.hp"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#LineBreak.hp"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#Text.hp"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#Text.copy"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#Text.copy$default$2"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#Text.this"),
+      ProblemFilters.exclude[MissingTypesProblem]("fs2.data.text.render.internal.Annotated$Text$"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#Text.apply"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("fs2.data.text.render.internal.Annotated#Text._2")
     )
   )
   .nativeSettings(

json/src/main/scala/fs2/data/json/package.scala

@@ -154,7 +154,71 @@ package object json {
       * You can use this to write the Json stream to a file.
       */
     def compact[F[_]]: Pipe[F, Token, String] =
-      _.through(fs2.data.text.render.pretty(width = Int.MaxValue)(Token.compact))
+      _.scanChunks((0, false)) { case (state, chunk) =>
+        val builder = new StringBuilder
+        val state1 =
+          chunk.foldLeft(state) {
+            case ((level, comma), Token.StartObject) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append(('{'))
+              (level + 1, false)
+            case ((level, _), Token.EndObject) =>
+              builder.append('}')
+              (level - 1, level > 1)
+            case ((level, comma), Token.StartArray) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append(('['))
+              (level + 1, false)
+            case ((level, _), Token.EndArray) =>
+              builder.append(']')
+              (level - 1, level > 1)
+            case ((level, comma), Token.Key(key)) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append('"')
+              Token.renderString(key, 0, builder)
+              builder.append("\":")
+              (level, false)
+            case ((level, comma), Token.StringValue(key)) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append('"')
+              Token.renderString(key, 0, builder)
+              builder.append('"')
+              (level, level > 0)
+            case ((level, comma), Token.NumberValue(n)) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append(n)
+              (level, level > 0)
+            case ((level, comma), Token.TrueValue) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append("true")
+              (level, level > 0)
+            case ((level, comma), Token.FalseValue) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append("false")
+              (level, level > 0)
+            case ((level, comma), Token.NullValue) =>
+              if (comma) {
+                builder.append(',')
+              }
+              builder.append("null")
+              (level, level > 0)
+          }
+        (state1, Chunk.singleton(builder.result()))
+      }
 
     /** Renders a pretty-printed representation of the token stream with the given
       * indentation size.

text/shared/src/main/scala/fs2/data/text/render/internal/Annotated.scala

@@ -18,13 +18,13 @@ package fs2.data.text.render.internal
 
 private sealed trait Annotated
 private object Annotated {
-  case class Text(text: String, hp: Int) extends Annotated
-  case class Line(hp: Int) extends Annotated
-  case class LineBreak(hp: Int) extends Annotated
+  case class Text(text: String) extends Annotated
+  case class Line(pos: Int) extends Annotated
+  case class LineBreak(pos: Int) extends Annotated
   case class GroupBegin(hpl: Position) extends Annotated
-  case class GroupEnd(hp: Int) extends Annotated
-  case class IndentBegin(hp: Int) extends Annotated
-  case class IndentEnd(hp: Int) extends Annotated
-  case class AlignBegin(hp: Int) extends Annotated
-  case class AlignEnd(hp: Int) extends Annotated
+  case object GroupEnd extends Annotated
+  case object IndentBegin extends Annotated
+  case object IndentEnd extends Annotated
+  case object AlignBegin extends Annotated
+  case object AlignEnd extends Annotated
 }

text/shared/src/main/scala/fs2/data/text/render/internal/NonEmptyIntList.scala

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2024 fs2-data Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package fs2.data.text.render.internal
+
+private sealed trait NonEmptyIntList {
+  def head: Int
+  def ::(i: Int): NonEmptyIntList =
+    More(i, this)
+  def incHead: NonEmptyIntList
+  def decHead: NonEmptyIntList
+  def pop: NonEmptyIntList
+}
+private final case class One(head: Int) extends NonEmptyIntList {
+  override def incHead: NonEmptyIntList = One(head + 1)
+  override def decHead: NonEmptyIntList = One(head - 1)
+  override lazy val pop: NonEmptyIntList = One(0)
+}
+private final case class More(head: Int, tail: NonEmptyIntList) extends NonEmptyIntList {
+  override def incHead: NonEmptyIntList = More(head + 1, tail)
+  override def decHead: NonEmptyIntList = More(head - 1, tail)
+  override def pop: NonEmptyIntList = tail
+}