Make scry faster and lightweight (#53)

* Implements lightweight features

* Avoid heavy compiler dependencies

* Use external process to free up memory

* Remove LLVM dependency

.travis.yml

@@ -15,7 +15,7 @@ matrix:
         - DEPLOY_DIR=bin/darwin
 
 install:
-  - bin/ci  prepare_build
+  - bin/ci prepare_build
 
 script:
   - bin/ci build

Dockerfile

@@ -1,7 +1,6 @@
 FROM crystallang/crystal:0.24.1
 
 RUN apt-get update
-RUN apt-get install -y llvm-4.0-dev
 RUN apt-get clean
 RUN rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 

README.md

@@ -17,7 +17,7 @@ The server is implemented in Crystal.
 
 To install scry download it from [releases page](https://github.com/crystal-lang-tools/scry/releases) or compile latest version using:
 
-> **Note:** crystal and LLVM are required in order to compile scry.
+> **Note:** crystal is required in order to compile scry.
 
 ```
 git clone https://github.com/crystal-lang-tools/scry.git
@@ -32,7 +32,7 @@ Then setup `scry` binary path on your LSP client.
 - Completion feature is still experimental.
 - Unexpected diagnostics can appear on files using implicit `require`, try using explicit `require` at top of your files.
 - Go to definition only work for some methods and variables. Go to classes or macros definition is not supported yet.
-- Symbol listing is per file, listing workspace symbols isn't supported yet.
+- Symbol listing works per file, searching for workspace symbols is not supported yet.
 
 ## Roadmap
 

bin/ci

@@ -65,8 +65,7 @@ prepare_build() {
   on_linux docker build -t crystal/scry-image .
 
   on_osx brew update
-  on_osx brew install llvm crystal-lang
-  on_osx brew link --overwrite --force llvm
+  on_osx brew install crystal-lang
 }
 
 
@@ -139,4 +138,4 @@ case $command in
       exit 1
     fi
     ;;
-esac
+esac

spec/scry/initialize_spec.cr

@@ -6,7 +6,7 @@ module Scry
       initer = Initializer.new(
         InitializeParams.from_json({
           processId:    1,
-          rootPath:     "/homa/main/Projects/Experiment",
+          rootPath:     "/home/main/Projects/Experiment",
           capabilities: {} of String => String,
           trace:        "off",
         }.to_json),

src/scry/analyzer.cr

@@ -1,4 +1,3 @@
-require "compiler/crystal/**"
 require "./workspace"
 require "./text_document"
 require "./publish_diagnostic"
@@ -26,17 +25,22 @@ module Scry
 
     # NOTE: compiler is a bit heavy in some projects.
     private def analyze(source)
-      source = Crystal::Compiler::Source.new(@text_document.filename, source)
-      compiler = Crystal::Compiler.new
-      compiler.color = false
-      compiler.no_codegen = true
-      compiler.debug = Crystal::Debug::None
-      compiler.compile(source, source.filename + ".out")
-      [@diagnostic.clean]
-    rescue ex : Crystal::Exception
-      @diagnostic.from(ex)
-    ensure
-      GC.collect
+      response = crystal_build(@text_document.filename, source)
+      if response.empty?
+        [@diagnostic.clean]
+      else
+        @diagnostic.from(response)
+      end
+    rescue ex
+      Log.logger.error("A error was found while searching diagnostics\n#{ex}")
+      nil
+    end
+
+    private def crystal_build(filename, source)
+      code = IO::Memory.new(source)
+      String.build do |io|
+        Process.run("crystal", ["build", "--no-codegen", "--no-color", "--error-trace", "-f", "json", "--stdin-filename", filename], output: io, error: io, input: code)
+      end
     end
   end
 end

src/scry/implementations.cr

@@ -1,5 +1,3 @@
-require "compiler/crystal/**"
-
 require "./log"
 require "./protocol/location"
 
@@ -21,29 +19,27 @@ module Scry
 
     # NOTE: compiler is a bit heavy in some projects.
     def search(filename, source, position)
-      source = Crystal::Compiler::Source.new(filename, source)
-      compiler = Crystal::Compiler.new
-      compiler.color = false
-      compiler.no_codegen = true
-      compiler.debug = Crystal::Debug::None
-      result = compiler.compile(source, filename + ".out")
-      loc = Crystal::Location.new(filename, position.line + 1, position.character + 1)
-      res = Crystal::ImplementationsVisitor.new(loc).process(result)
-      Log.logger.debug(res)
-      impls = res.implementations
-      if res.status == "ok" && impls
+      response = crystal_tool(filename, position)
+      parsed_response = JSON.parse(response)
+      impls = parsed_response["implementations"]?
+      if impls
         locations = impls.map do |impl|
-          pos = Position.new(impl.line, impl.column)
+          pos = Position.new(impl["line"].as_i, impl["column"].as_i)
           range = Range.new(pos, pos)
-          Location.new("file://" + impl.filename, range)
+          Location.new("file://" + impl["filename"].as_s, range)
         end
         ResponseMessage.new(@text_document.id, locations)
       end
     rescue ex
       Log.logger.error("A error was found while searching definitions\n#{ex}")
       nil
-    ensure
-      GC.collect
+    end
+
+    private def crystal_tool(filename, position)
+      location = "#{filename}:#{position.line + 1}:#{position.character + 1}"
+      String.build do |io|
+        Process.run("crystal", ["tool", "implementations", "--no-color", "--error-trace", "-f", "json", "-c", "#{location}", filename], output: io, error: io)
+      end
     end
   end
 end

src/scry/missing_methods.cr

@@ -0,0 +1,17 @@
+# HACK: to avoid requiring the whole compiler
+module Crystal
+  struct CrystalPath
+    class Error
+      def to_s_with_source(source, io)
+      end
+    end
+  end
+
+  class Exception
+    def to_json_single(json)
+      json.object do
+        json.field "message", @message
+      end
+    end
+  end
+end

src/scry/parse_analyzer.cr

@@ -1,8 +1,9 @@
-require "compiler/crystal/**"
-
+require "compiler/crystal/syntax"
+require "compiler/crystal/crystal_path"
 require "./workspace"
 require "./text_document"
 require "./publish_diagnostic"
+require "./missing_methods"
 
 module Scry
   struct ParseAnalyzer
@@ -20,7 +21,7 @@ module Scry
       parser.parse
       [@diagnostic.clean]
     rescue ex : Crystal::Exception
-      @diagnostic.from(ex)
+      @diagnostic.from(ex.to_json)
     end
   end
 end

src/scry/publish_diagnostic.cr

@@ -26,7 +26,7 @@ module Scry
     end
 
     def from(ex)
-      build_failures = Array(BuildFailure).from_json(ex.to_json)
+      build_failures = Array(BuildFailure).from_json(ex)
       build_failures
         .uniq
         .first(@workspace.max_number_of_problems)