java based subprocess_run from matlab-subprocess-stdin

testSys: update env test for new subprocess_run

Author: scivision

+stdlib/+sys/subprocess_run.m

@@ -1,55 +1,73 @@
-function [status, msg] = subprocess_run(cmd_array, opt)
-
+function [status, stdout, stderr] = subprocess_run(cmd, opt)
+% SUBPROCESS_RUN run a program with arguments and options
+% uses Matlab Java ProcessBuilder interface to run subprocess and use stdin/stdout pipes
 arguments
-  cmd_array (1,:) string
+  cmd (1,:) string
   opt.env struct {mustBeScalarOrEmpty} = struct.empty
   opt.cwd string {mustBeScalarOrEmpty} = string.empty
+  opt.stdin string {mustBeScalarOrEmpty} = string.empty
 end
 
-exe = space_quote(cmd_array(1));
+%% process instantiation
+proc = java.lang.ProcessBuilder("");
 
-if length(cmd_array) > 1
-  cmd = append(exe, " ", join(cmd_array(2:end), " "));
-else
-  cmd = exe;
+if ~isempty(opt.env)
+  % requires Parallel Computing Toolbox
+  env = proc.environment();
+  fields = fieldnames(opt.env);
+  for i = 1:length(fields)
+    env.put(fields{i}, opt.env.(fields{i}));
+  end
 end
 
 if ~isempty(opt.cwd)
   mustBeFolder(opt.cwd)
-  cwd = stdlib.fileio.absolute_path(opt.cwd);
-  oldcwd = pwd;
-  cd(cwd)
+  proc.directory(java.io.File(opt.cwd));
 end
 
-old = isMATLABReleaseOlderThan('R2022b');
-if old && ~isempty(opt.env)
-  warning("Matlab >= R2022b required for 'env' option of subprocess_run()")
+proc.command(cmd);
+%% start process
+h = proc.start();
+
+%% stdin pipe
+if ~isempty(opt.stdin)
+  writer = java.io.BufferedWriter(java.io.OutputStreamWriter(h.getOutputStream()));
+  writer.write(opt.stdin);
+  writer.flush()
+  writer.close()
 end
 
-if isempty(opt.env) || old
-  [status, msg] = system(cmd);
-else
-  envCell = namedargs2cell(opt.env);
-  % https://www.mathworks.com/help/matlab/ref/system.html
-  [status, msg] = system(cmd, envCell{:});
+%% wait for process to complete
+% https://docs.oracle.com/javase/9/docs/api/java/lang/Process.html#waitFor--
+status = h.waitFor();
+
+%% read stdout, stderr pipes
+stdout = read_stream(h.getInputStream());
+stderr = read_stream(h.getErrorStream());
+
+%% close process
+h.destroy()
+
+if nargout < 2 && strlength(stdout) > 0
+  disp(stdout)
 end
-if ~isempty(opt.cwd)
-  cd(oldcwd)
+if nargout < 3 && strlength(stderr) > 0
+  warning(stderr)
 end
 
-end
+end % function subprocess_run
 
 
-function q = space_quote(p)
-arguments
-  p (1,1) string
-end
+function msg = read_stream(stream)
 
-if ~contains(p, " ")
-  q = p;
-  return
+reader = java.io.BufferedReader(java.io.InputStreamReader(stream));
+line = reader.readLine();
+msg = "";
+while ~isempty(line)
+  msg = append(msg, string(line), newline);
+  line = reader.readLine();
 end
-
-q = append('"', p, '"');
+msg = strip(msg);
+reader.close()
 
 end

+stdlib/+test/TestSys.m

@@ -19,27 +19,25 @@ function test_simple_run(tc)
 
 function test_env_run(tc)
 
-tc.assumeFalse(isMATLABReleaseOlderThan('R2022b'), "system(..., EnvName=, EnvVal=) requires Matlab R2022b+")
-
 names = ["TEST1", "TEST2"];
 vals = ["test123", "test321"];
 
 env = struct(names(1), vals(1), names(2), vals(2));
 
-% NOTE: test function cannot get specific variables without invoking a
-% subshell, as echo is evaluated in current shell before &&
-% Thus we just print the entire environment
-if ispc
-  c = "set";
-else
-  c = "env";
+for i = 1:length(names)
+  if ispc
+    % in ComSpec, echo is a special shell cmd like "dir" -- also doesn't
+    % work in python subprocess.run
+    cmd = ["pwsh", "-c" "(Get-ChildItem Env:" + names(i) + ").Value"];
+  else
+    cmd = ["sh", "-c", "echo $" + names(i)];
+  end
+
+  [ret, out] = stdlib.subprocess_run(cmd, env=env);
+  tc.verifyEqual(ret, 0)
+  tc.verifyTrue(contains(out, vals(i)))
 end
 
-[ret, msg] = stdlib.subprocess_run(c, env=env);
-tc.verifyEqual(ret, 0)
-tc.verifyTrue(contains(msg, names(1) + "=" + vals(1)))
-tc.verifyTrue(contains(msg, names(2) + "=" + vals(2)))
-
 end
 
 function test_find_fortran(tc)

+stdlib/subprocess_run.m

@@ -1,4 +1,4 @@
-function [status, msg] = subprocess_run(cmd_array, opt)
+function [status, stdout, stderr] = subprocess_run(cmd_array, opt)
 %% subprocess_run(cmd_array, opt)
 % handle command lines with spaces
 % input each segment of the command as an element in a string array
@@ -7,14 +7,16 @@
 % * cmd_array: vector of string to compose a command line
 % * opt.env: environment variable struct to set
 % * opt.cwd: working directory to use while running command
+% * opt.stdin: string to pass to subprocess stdin pipe
 %%% Outputs
 % * status: 0 is success
-% * msg: stderr + stdout from process
+% * stdout: stdout from process
+% * stderr: stderr from process
 %
 %% Example
 % subprocess_run(["mpiexec", "-help2"])
-% subprocess_run(["ls", "-l"])
-% subprocess_run(["dir", "/Q", "/L"])
+% subprocess_run(["sh", "-c", "ls", "-l"])
+% subprocess_run(["cmd", "/c", "dir", "/Q", "/L"])
 %
 % NOTE: if cwd option used, any paths must be absolute or relative to cwd.
 % otherwise, they are relative to pwd.
@@ -23,9 +25,10 @@
   cmd_array (1,:) string
   opt.env struct {mustBeScalarOrEmpty} = struct.empty
   opt.cwd string {mustBeScalarOrEmpty} = string.empty
+  opt.stdin string {mustBeScalarOrEmpty} = string.empty
 end
 
-[status, msg] = stdlib.sys.subprocess_run(cmd_array, ...
-'env', opt.env, 'cwd', opt.cwd);
+[status, stdout, stderr] = stdlib.sys.subprocess_run(cmd_array, ...
+'env', opt.env, 'cwd', opt.cwd, "stdin", opt.stdin);
 
 end