lib/exec: intro `ProcessDuplex::write_and_read`

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/standard/exec.nit b/lib/standard/exec.nit
index 517edf3..3e0d97a 100644 (file)
--- a/lib/standard/exec.nit
+++ b/lib/standard/exec.nit
@@ -272,9 +272,49 @@ class ProcessDuplex
 
        redef fun pipeflags do return 3
 
-       redef fun execute
+       redef fun execute do super
+
+       # Write `input` to process and return its output
+       #
+       # Writing and reading are processed line by line,
+       # reading only when something is available.
+       #
+       # ~~~
+       # var proc = new ProcessDuplex("tr", "[:lower:]", "[:upper:]")
+       # assert proc.write_and_read("""
+       #     Alice
+       #     Bob
+       # """) == """
+       #     ALICE
+       #     BOB
+       # """
+       # ~~~
+       fun write_and_read(input: Text): String
        do
-               super
+               var read = new Buffer #new Array[String]
+
+               # Main loop, read and write line by line
+               var prev = 0
+               for delimiter in input.search_all('\n') do
+                       write input.substring(prev, delimiter.after-prev)
+                       prev = delimiter.after
+
+                       while stream_in.poll_in do
+                               read.append stream_in.read_line
+                       end
+               end
+
+               # Write the last line
+               write input.substring_from(prev)
+               stream_out.close
+
+               # Read the rest, may be everything for some programs
+               read.append stream_in.read_all
+               stream_in.close
+
+               # Clean up
+               wait
+               return read.to_s
        end
 end