Support extension (#83)

* init implementation for extension

only get_extension/put_extension without encoding/decoding and protoc

* support decoding and encoding for extension

* generate code for extensions

* finish extension

* ci: fix integration test

* improve docs

* mix format

* update README and CLI doc

* filter extension module by name first

* regenerate protos

* doc: add custom options to README

Author: tony612

.formatter.exs

@@ -1,8 +1,8 @@
 
 [
   inputs: ["mix.exs", "{config,lib,test}/**/*.{ex,exs}"],
-  locals_without_parens: [field: 2, field: 3, oneof: 2],
+  locals_without_parens: [field: 2, field: 3, oneof: 2, extend: 4, extensions: 1],
   export: [
-    locals_without_parens: [field: 2, field: 3, oneof: 2]
+    locals_without_parens: [field: 2, field: 3, oneof: 2, extend: 4, extensions: 1]
   ]
 ]

.travis.yml

@@ -3,7 +3,6 @@ language: elixir
 git:
   depth: 3
 elixir:
-  - 1.6
   - 1.7
   - 1.8
   - 1.9
@@ -12,9 +11,8 @@ otp_release:
   - 21.3
   - 22.0
 matrix:
-  exclude:
-  - elixir: 1.6
-    otp_release: 22.0
+  allow_failures:
+  - otp_release: 20.3
 env:
   - MIX_ENV=test VERBOSE_TESTS=true
 install:
@@ -23,8 +21,8 @@ install:
   - mix deps.get
   - mix eqc.install --mini --force
 before_script:
-  - wget https://github.com/google/protobuf/releases/download/v3.3.0/protoc-3.3.0-linux-x86_64.zip
-  - unzip protoc-3.3.0-linux-x86_64.zip
+  - wget https://github.com/protocolbuffers/protobuf/releases/download/v3.11.2/protoc-3.11.2-linux-x86_64.zip
+  - unzip protoc-3.11.2-linux-x86_64.zip
   - export PATH=$PATH:$PWD/bin/
 script:
   - mix test

Makefile

@@ -4,22 +4,16 @@ protoc-gen-elixir:
 	mix escript.build .
 
 clean:
-	rm protoc-gen-elixir
+	rm -f protoc-gen-elixir
 
 # PROTO_LIB should be your local path to https://github.com/google/protobuf/tree/master/src/google/protobuf
-gen_google_proto: protoc-gen-elixir
+gen-google-protos: protoc-gen-elixir
 	$(call ndef,PROTO_LIB)
-	protoc -I $(PROTO_LIB) --elixir_out=lib/google --plugin=./protoc-gen-elixir $(PROTO_LIB)/descriptor.proto
-	protoc -I $(PROTO_LIB) --elixir_out=lib/google --plugin=./protoc-gen-elixir $(PROTO_LIB)/compiler/plugin.proto
+	protoc -I $(PROTO_LIB) --elixir_out=lib/google --plugin=./protoc-gen-elixir descriptor.proto
+	protoc -I $(PROTO_LIB) --elixir_out=lib/google --plugin=./protoc-gen-elixir compiler/plugin.proto
 
-	# it's a hack until extension is implemented
-	# 1047 is allocated to this project by Google
-	sed -i "" '/field :ruby_package, 45/a \
-	\ \ field :elixir_module_prefix, 1047, optional: true, type: :string\
-	' lib/google/descriptor.pb.ex
+gen-protos: protoc-gen-elixir
+	protoc -I src -I test/protobuf/protoc/proto --elixir_out=test/protobuf/protoc/proto_gen --plugin=./protoc-gen-elixir test/protobuf/protoc/proto/*.proto
+	protoc -I src --elixir_out=lib --plugin=./protoc-gen-elixir elixirpb.proto
 
-	sed -i "" '/    :ruby_package,/a \
-	\ \ \ \ :elixir_module_prefix,\
-	' lib/google/descriptor.pb.ex
-
-.PHONY: clean gen_google_proto
+.PHONY: clean gen_google_proto gen_test_protos

README.md

@@ -22,9 +22,10 @@ The package can be installed by adding `protobuf` to your list of dependencies i
 ```elixir
 def deps do
   [
-    {:protobuf, "~> 0.5.3"},
+    {:protobuf, "~> 0.7.1"},
     # Only for files generated from Google's protos.
     # Can be ignored if you don't use Google's protos.
+    # Or you can generate the code by yourself.
     {:google_protos, "~> 0.1"}
   ]
 end
@@ -44,6 +45,7 @@ end
 * [x] Validate values
 * [x] Generate typespecs
 * [x] oneof
+* [x] (proto2) Extension (Experiment, see `Protobuf.Extension`)
 
 ## Usage
 
@@ -94,7 +96,6 @@ struct = Foo.decode(encoded)
 
 Note:
 - You should use `YourModule.new` instead of using the struct directly because default values will be set for all fields.
-- Default values will be set by default in `decode`, which can be changed by `:use_default` option.
 - Validation is done in `encode`. An error will be raised if the struct is invalid(like type is not matched).
 
 ### Descriptor support
@@ -126,6 +127,26 @@ $ protoc --elixir_out=./lib --plugin=./protoc-gen-elixir *.proto
 $ protoc -I protos --elixir_out=./lib protos/hello.proto
 ```
 
+### Custom options
+
+Since extensions(`Protobuf.Extension`) is supported now, some options are defined, like custom module_prefix.
+
+1. Copy src/elixirpb.proto to your protos path
+2. Import elixirpb.proto and use the options
+
+```proto
+syntax = "proto2";
+
+package your.pkg;
+
+import "elixirpb.proto";
+
+option (elixirpb.file).module_prefix = "Foo.Bar";
+```
+3. Generate code as before
+
+More options will be added in the future, see elixirpb.proto comments for details.
+
 ## Tests
 
 Before you can run the test suite, you must install `eqc_gen`:

lib/application.ex

@@ -0,0 +1,39 @@
+defmodule Protobuf.Application do
+  use Application
+
+  @moduledoc """
+  When extensions feature is enabled, all modules are scanned to fetch
+  runtime information for extensions, see `Protobuf.Extension` for details.
+
+  No children are created now.
+  """
+
+  @doc false
+  def start(_type, _args) do
+    if Application.get_env(:protobuf, :extensions, :disabled) == :enabled do
+      mods = get_all_modules()
+      Protobuf.Extension.cal_extensions(mods)
+    else
+      # Extensions in Protobuf should always be calculated for generating code
+      {:ok, mods} = :application.get_key(:protobuf, :modules)
+      Protobuf.Extension.cal_extensions(mods)
+    end
+
+    children = []
+    Supervisor.start_link(children, strategy: :one_for_one)
+  end
+
+  defp get_all_modules() do
+    case :code.get_mode() do
+      :embedded ->
+        :erlang.loaded()
+
+      :interactive ->
+        for {app, _, _} <- Application.loaded_applications() do
+          {:ok, modules} = :application.get_key(app, :modules)
+          modules
+        end
+        |> Enum.concat()
+    end
+  end
+end

lib/elixirpb.pb.ex

@@ -0,0 +1,18 @@
+defmodule Elixirpb.FileOptions do
+  @moduledoc false
+  use Protobuf, syntax: :proto2
+
+  @type t :: %__MODULE__{
+          module_prefix: String.t()
+        }
+  defstruct [:module_prefix]
+
+  field :module_prefix, 1, optional: true, type: :string
+end
+
+defmodule Elixirpb.PbExtension do
+  @moduledoc false
+  use Protobuf, syntax: :proto2
+
+  extend Google.Protobuf.FileOptions, :file, 1047, optional: true, type: Elixirpb.FileOptions
+end

lib/google/compiler/plugin.pb.ex

@@ -34,20 +34,6 @@ defmodule Google.Protobuf.Compiler.CodeGeneratorRequest do
   field :compiler_version, 3, optional: true, type: Google.Protobuf.Compiler.Version
 end
 
-defmodule Google.Protobuf.Compiler.CodeGeneratorResponse do
-  @moduledoc false
-  use Protobuf, syntax: :proto2
-
-  @type t :: %__MODULE__{
-          error: String.t(),
-          file: [Google.Protobuf.Compiler.CodeGeneratorResponse.File.t()]
-        }
-  defstruct [:error, :file]
-
-  field :error, 1, optional: true, type: :string
-  field :file, 15, repeated: true, type: Google.Protobuf.Compiler.CodeGeneratorResponse.File
-end
-
 defmodule Google.Protobuf.Compiler.CodeGeneratorResponse.File do
   @moduledoc false
   use Protobuf, syntax: :proto2
@@ -63,3 +49,17 @@ defmodule Google.Protobuf.Compiler.CodeGeneratorResponse.File do
   field :insertion_point, 2, optional: true, type: :string
   field :content, 15, optional: true, type: :string
 end
+
+defmodule Google.Protobuf.Compiler.CodeGeneratorResponse do
+  @moduledoc false
+  use Protobuf, syntax: :proto2
+
+  @type t :: %__MODULE__{
+          error: String.t(),
+          file: [Google.Protobuf.Compiler.CodeGeneratorResponse.File.t()]
+        }
+  defstruct [:error, :file]
+
+  field :error, 1, optional: true, type: :string
+  field :file, 15, repeated: true, type: Google.Protobuf.Compiler.CodeGeneratorResponse.File
+end