refactor: run now return stdout or stderr with status

with Exec::IO::MultiWriter
we can print and get output both

Author: initdc

shard.yml

@@ -1,5 +1,5 @@
 name: exec
-version: 0.1.1
+version: 0.2.0
 
 authors:
   - initdc <initd@outlook.com>

src/exec.cr

@@ -1,11 +1,47 @@
 class Exec < Process
-  VERSION = "0.1.1"
+  VERSION = "0.2.0"
+
+  class IO
+    class MultiWriter < ::IO::MultiWriter
+      alias IO = ::IO | ::IO::FileDescriptor | ::String::Builder
+
+      def read(slice : Bytes) : NoReturn
+        raise ::IO::Error.new("Can't read from IO::MultiWriter")
+      end
+    end
+  end
 
   def self.run(command : String, args = nil, env : Env = nil, clear_env : Bool = false, shell : Bool = true,
-               input : Stdio = Redirect::Inherit, output : Stdio = Redirect::Inherit, error : Stdio = Redirect::Inherit, chdir : Path | String? = nil) : Process::Status
-    status = new(command, args, env, clear_env, shell, input, output, error, chdir).wait
+               input : Stdio = Redirect::Inherit, output : Stdio = Redirect::Inherit, error : Stdio = Redirect::Inherit, chdir : Path | String? = nil) : String | {String, Process::Status}
+    output_strio = String::Builder.new
+    error_strio = String::Builder.new
+
+    output_writer = if output.is_a?(Redirect)
+                      output == Redirect::Close ? output : Exec::IO::MultiWriter.new(STDOUT, output_strio)
+                    else
+                      Exec::IO::MultiWriter.new(STDOUT, output, output_strio)
+                    end
+
+    error_writer = if error.is_a?(Redirect)
+                     error == Redirect::Close ? error : Exec::IO::MultiWriter.new(STDOUT, error_strio)
+                   else
+                     Exec::IO::MultiWriter.new(STDOUT, error, error_strio)
+                   end
+
+    status = new(command, args, env, clear_env, shell, input, output_writer, error_writer, chdir).wait
     $? = status
-    status
+
+    output.close unless output.is_a?(Redirect)
+    error.close unless error.is_a?(Redirect)
+    output_strio.close
+    error_strio.close
+
+    case status.success?
+    when true
+      output_strio.to_s
+    else
+      {error_strio.to_s, status}
+    end
   end
 
   def self.code(command : String, args = nil, env : Env = nil, clear_env : Bool = false, shell : Bool = true,