Add cflamegraph schema

.gitignore

@@ -8,3 +8,4 @@ visualization/node_modules/
 /protobuf/src/main/gen/*
 /visualization/static/js/generated/*
 protobuf/generated/main/
+/src/gen/

build.gradle

@@ -1,3 +1,5 @@
+import io.netifi.flatbuffers.plugin.tasks.FlatBuffers
+
 buildscript {
     ext.kotlin_version = '1.2.51'
     repositories {
@@ -28,6 +30,8 @@ plugins {
     id 'com.google.protobuf' version '0.8.6' apply false
     id 'com.moowork.node' version '1.2.0'
     id 'com.liferay.soy' version '3.1.6'
+    id "io.netifi.flatbuffers" version "1.0.4"
+    id 'idea'
 }
 
 allprojects {
@@ -56,6 +60,7 @@ configurations {
 
 dependencies {
     compile group: 'com.google.code.gson', name: 'gson', version: '2.8.1'
+    compile group: 'com.github.davidmoten', name: 'flatbuffers-java', version: '1.9.0.1'
     compile fileTree(dir: 'lib', include: ['com.jrockit.mc.flightrecorder_5.5.1.172852.jar'])
     compile fileTree(dir: 'lib', include: ['com.jrockit.mc.common_5.5.1.172852.jar'])
     compile fileTree(dir: 'lib', include: ['flight-recorder-parser-for-java-9.jar'])
@@ -126,6 +131,23 @@ compileTestKotlin {
     }
 }
 
+flatbuffers {
+    flatcPath = '/usr/local/bin/flatc'
+    language = 'java'
+}
+
+task compileFlatBuffers(type: FlatBuffers) {
+    inputDir = file("src/main/flatbuffers")
+    outputDir = file("src/gen/java")
+}
+
+sourceSets.main.java.srcDir file('src/gen/java')
+idea {
+    module {
+        generatedSourceDirs += file('src/gen/java')
+    }
+}
+
 /* if have some problems with jmh - execute clean first */
 jmh {
     /* jmh Jar warns about duplicate dependencies

src/main/flatbuffers/cflamegraph_schema.fbs

@@ -0,0 +1,22 @@
+namespace com.github.kornilova_l.flamegraph.cflamegraph;
+
+table Names {
+  class_names:[string];
+  method_names:[string];
+  descriptions:[string];
+}
+
+struct Node {
+  class_name_id:int; // -1 if class name is not set
+  method_name_id:int;
+  description_id:int; // -1 if description is not set
+  width:int;
+  depth:int;
+}
+
+table Tree {
+  names:Names;
+  nodes:[Node];
+}
+
+root_type Tree;

src/main/java/com/github/kornilova_l/flamegraph/plugin/server/converters/file_to_call_traces/cflamegraph/CompressedFlamegraphToCallTracesConverter.kt

@@ -7,64 +7,48 @@ import java.io.File
 
 
 /**
- * Original flamegraph format consumes a lot of memory on disk and it takes more time to parse
- * because it has lots of duplicate parts of call traces.
+ * Original flamegraph format consumes a lot of memory on disk and it takes more
+ * time to parse because it has lots of duplicate parts of call traces.
  * cflamegraph (compressed flamegraph) solves this problem.
+ * It uses FlatBuffers for data serialization and does not duplicate
+ * class names, method names and descriptions.
  *
- * Header of file contains ids of class names, method names and descriptions.
- * For example:
- * C
- * ClassName1 0
- * ClassName2 1
- * M
- * method1 0
- * method2 1
- * D
- * () 0
- * (int)int 1
- *
- * Each line of cflamegraph contains information in following format:
- * C=<class name id> M=<method name id> D=<description id> w=<width> d=<depth>
- *
- * C and D are optional.
+ * See scheme in /src/main/flatbuffers/cflamegraph_schema.fbs
  *
  * Example:
  * ._ _
  * |c|d|___ _
  * |b()____|e|_______ _
  * |Class.a__________|f|
  *
- * --C-- 1
- * Class 0
- * --M-- 6
- * a 0
- * b 1
- * c 2
- * d 3
- * e 4
- * f 5
- * --D-- 1
- * () 0
- * C0M0w100d1
- * M1w40d2
- * M2w5d3
- * M3w5d3
- * M4w5d2
- * M5w5d1
- *
- * As you can see order of lines matters
- * because if a call has bigger depth than previous it means that
- * the call is a child of previous call.
- *
  * In original flamegraph format this example would look like this:
- * a;b;c 5
- * a;b;d 5
- * a;b 10
+ * a;b();c 5
+ * a;b();d 5
+ * a;b() 10
  * a;e 5
  * a 50
  * f 5
  *
- * In cflamegraph files strings are not duplicated and equal parts of stacktraces are also not duplicated.
+ * Serialized with flatbuffers tree will have following structure:
+ * Names: {
+ *   classNames: ["Class"],
+ *   methodNames: ["a", "b", "c", "d", "e", "f"],
+ *   descriptions: ["()"]
+ * }
+ * Tree: {
+ *   nodes: [
+ *     { class_name_id: 0, method_name_id: 0, width: 100, depth: 1 },
+ *     { method_name_id: 1, description_id: 0, width: 40, depth: 2 },
+ *     { method_name_id: 2, width: 5, depth: 3 },
+ *     { method_name_id: 3, width: 5, depth: 3 },
+ *     { method_name_id: 4, width: 5, depth: 2 },
+ *     { method_name_id: 5, width: 5, depth: 1 }
+ *   ]
+ * }
+ *
+ * Order of nodes matters.
+ * If a call has bigger depth than previous it means that the call is a child
+ * of previous call.
  *
  * Converter merges unmerged stacktraces.
  */