Simple Elixir Port manager process

Author: GregMefford

Makefile

@@ -5,19 +5,15 @@
 # CFLAGS        compiler flags for compiling all C files
 # LDFLAGS       linker flags for linking all binaries
 
-# Initialize some variables if not set
-LDFLAGS ?=
-CFLAGS ?= -O2 -Wall -Wextra -Wno-unused-parameter -g
+LDFLAGS += -lzbar -ljpeg
+CFLAGS += -Wall -std=gnu99
 CC ?= $(CROSSCOMPILE)-gcc
 
-DEFAULT_TARGETS ?= priv priv/zbar_scanner
-
-# Link in all of the VideoCore libraries
-LDFLAGS +=-lzbar -ljpeg
-
 SRC=src/zbar_scanner.c
 OBJ=$(SRC:.c=.o)
 
+DEFAULT_TARGETS ?= priv priv/zbar_scanner
+
 .PHONY: all clean
 
 all: $(DEFAULT_TARGETS)

config/config.exs

@@ -1,30 +1 @@
-# This file is responsible for configuring your application
-# and its dependencies with the aid of the Mix.Config module.
 use Mix.Config
-
-# This configuration is loaded before any dependency and is restricted
-# to this project. If another project depends on this project, this
-# file won't be loaded nor affect the parent project. For this reason,
-# if you want to provide default values for your application for
-# 3rd-party users, it should be done in your "mix.exs" file.
-
-# You can configure for your application as:
-#
-#     config :zbar, key: :value
-#
-# And access this configuration in your application as:
-#
-#     Application.get_env(:zbar, :key)
-#
-# Or configure a 3rd-party app:
-#
-#     config :logger, level: :info
-#
-
-# It is also possible to import configuration files, relative to this
-# directory. For example, you can emulate configuration per environment
-# by uncommenting the line below and defining dev.exs, test.exs and such.
-# Configuration from the imported file will override the ones defined
-# here (which is why it is important to import them last).
-#
-#     import_config "#{Mix.env}.exs"

lib/zbar.ex

@@ -1,18 +1,35 @@
 defmodule Zbar do
   @moduledoc """
-  Documentation for Zbar.
+  Scan one or more barcodes found in a JPEG image using the zbar library.
   """
+  require Logger
 
   @doc """
-  Hello world.
+  Returns {exit_status, "binary output from zbar_scanner"}
+  """
+  def scan(filename) do
+    {:spawn_executable, zbar_binary()}
+    |> Port.open([
+      {:args, [filename]},
+      :binary,
+      :stream,
+      :exit_status,
+      :use_stdio,
+      :stderr_to_stdout
+    ])
+    |> handle_output()
+  end
 
-  ## Examples
+  defp handle_output(port, buffer \\ "") do
+    receive do
+      {^port, {:data, data}} ->
+        Logger.debug(buffer <> to_string(data))
+        handle_output(port, buffer <> to_string(data))
+      {^port, {:exit_status, status}} ->
+        {status, buffer}
+    end
+  end
 
-      iex> Zbar.hello
-      :world
+  defp zbar_binary, do: Path.join(:code.priv_dir(:zbar), "zbar_scanner")
 
-  """
-  def hello do
-    :world
-  end
 end

mix.exs

@@ -4,7 +4,10 @@ defmodule Zbar.Mixfile do
   def project do
     [app: :zbar,
      version: "0.1.0",
+     description: "Scan one or more barcodes from a JPEG image",
      elixir: "~> 1.4",
+     make_clean: ["clean"],
+     compilers: [:elixir_make | Mix.compilers()],
      build_embedded: Mix.env == :prod,
      start_permanent: Mix.env == :prod,
      compilers: [:elixir_make] ++ Mix.compilers,
@@ -29,6 +32,6 @@ defmodule Zbar.Mixfile do
   #
   # Type "mix help deps" for more examples and options
   defp deps do
-    []
+    [{:elixir_make, "~> 0.4", runtime: false}]
   end
 end

mix.lock

@@ -0,0 +1 @@
+%{"elixir_make": {:hex, :elixir_make, "0.4.0", "992f38fabe705bb45821a728f20914c554b276838433349d4f2341f7a687cddf", [], [], "hexpm"}}

src/zbar_scanner.c

@@ -1,6 +1,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <err.h>
 
 #include <jpeglib.h>