Implement concurrent_runner

2 files changed, 414 insertions, 2 deletions

diff --git a/build2/test/script/runner.cxx b/build2/test/script/runner.cxx
index 3a5eb76..051d0f8 100644
--- a/build2/test/script/runner.cxx
+++ b/build2/test/script/runner.cxx
@@ -2,9 +2,18 @@
 // copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
 // license   : MIT; see accompanying LICENSE file
 
+#ifndef _WIN32
+#  include <sys/wait.h>  // WIFEXITED(), WEXITSTATUS()
+#endif
+
+#include <iostream> // cerr
+
+#include <butl/filesystem> // auto_rm
+
 #include <build2/test/script/runner>
 
 using namespace std;
+using namespace butl;
 
 namespace build2
 {
@@ -29,11 +38,231 @@ namespace build2
         print_test (r, t);
       }
 
+      // Test command output cache. The usage is as follows:
+      //
+      // 1. Call wopen() to open the stream in write mode and register the file
+      //    for auto-removal by dtor.
+      //
+      // 2. Pass the file descriptor to the test command process ctor to
+      //    redirect it's output to the cache file.
+      //
+      // 3. Close the stream.
+      //
+      // 4. Call ropen() to open the file in read mode to match the content to
+      //    a pattern, cancel the file removal if the match fails (so the
+      //    output is available for troubleshooting).
+      //
+      class stream_cache: public ifdstream
+      {
+      public:
+        using path_type = butl::path;
+
+        stream_cache (const char* n): name (n) {}
+
+        // Open stream for writing. Return the file descriptor. Must not be
+        // called multiple times.
+        //
+        int
+        wopen ()
+        {
+          // Otherwise compiler gets confused with basic_ios::fail().
+          //
+          using build2::fail;
+
+          assert (!exists ());
+
+          try
+          {
+            // @@ Later it will make sense to create the file in the
+            //    test-specific temporary directory.
+            //
+            path = path_type::temp_path ("build2");
+          }
+          catch (const system_error& e)
+          {
+            fail << "unable to create temporary file: " << e.what ();
+          }
+
+          try
+          {
+            open (path, out | trunc);
+            cleanup = auto_rm<path_type> (path);
+          }
+          catch (const io_error& e)
+          {
+            fail << "unable to write " << path << ": " << e.what ();
+          }
+
+          return fd ();
+        }
+
+        // Open stream for reading. Return true if the file is not empty,
+        // false otherwise. Must not be called before wopen().
+        //
+        bool
+        ropen ()
+        {
+          // Otherwise compiler gets confused with basic_ios::fail().
+          //
+          using build2::fail;
+
+          assert (exists ());
+
+          try
+          {
+            open (path, in);
+            return peek () != ifdstream::traits_type::eof ();
+          }
+          catch (const io_error& e)
+          {
+            error << "unable to read " << path << ": " << e.what ();
+            throw failed ();
+          }
+        }
+
+        // Return true if wopen() was called, false otherwise.
+        //
+        bool
+        exists () const {return !path.empty ();}
+
+        ~stream_cache () override
+        {
+          close (); // Close the stream prior to the file deletion.
+        }
+
+      public:
+        string name;
+        path_type path;
+        auto_rm<path_type> cleanup;
+      };
+
+      // Check if the test command output matches the pattern (redirect value).
+      //
+      static void
+      check_output (const process_path& program,
+                    stream_cache& sc,
+                    const redirect& rd)
+      {
+        if (rd.type == redirect_type::none)
+        {
+          // Check that the cache file is empty.
+          //
+          if (sc.ropen ())
+          {
+            sc.cleanup.cancel ();
+
+            fail << program << " unexpectedly writes to " << sc.name <<
+                info << sc.name << " is saved to " << sc.path;
+          }
+        }
+        else if (rd.type == redirect_type::here_string ||
+                 rd.type == redirect_type::here_document)
+        {
+          // Use diff utility to compare the output with the pattern.
+          //
+          path dp ("diff");
+          process_path pp (run_search (dp, true));
+
+          cstrings args {
+            pp.recall_string (),
+            "--strip-trailing-cr",
+            "-u",
+            "-",
+            sc.path.string ().c_str (),
+            nullptr};
+
+          if (verb >= 2)
+            print_process (args);
+
+          try
+          {
+            // Diff utility prints the differences to stdout. But for the user
+            // it is a part of the test failure diagnostics so let's redirect
+            // stdout to stderr.
+            //
+            process pr (pp, args.data (), -1, 2);
+
+            try
+            {
+              ofdstream os (pr.out_fd);
+
+              auto write_value = [&os, &rd] ()
+              {
+                os << rd.value;
+
+                // Here-document is always endline-terminated.
+                //
+                if (rd.type == redirect_type::here_string)
+                  os << endl;
+
+                os.close ();
+              };
+
+              write_value ();
+
+              if (pr.wait ())
+                return;
+
+              // Output doesn't match the pattern string. Keep non-empty output
+              // and save the pattern for troubleshooting.
+              //
+              path p (sc.path + ".pattern");
+
+              try
+              {
+                os.open (p);
+                write_value ();
+              }
+              catch (const io_error& e)
+              {
+                fail << "unable to write " << p << ": " << e.what ();
+              }
+
+              diag_record d (error);
+              d << program << " " << sc.name
+                << " doesn't match the pattern";
+
+              if (sc.ropen ())
+              {
+                sc.cleanup.cancel ();
+                d << info << sc.name << " is saved to " << sc.path;
+              }
+              else
+                d << info << sc.name << " is empty";
+
+              // Pattern is never empty (contains at least newline).
+              //
+              d << info << sc.name << " pattern is saved to " << p;
+
+              // Fall through.
+              //
+            }
+            catch (const io_error& e)
+            {
+              // Child exit status doesn't matter. Assume the child process
+              // issued diagnostics. Just wait for the process completion.
+              //
+              pr.wait (); // Check throw.
+            }
+
+            // Fall through.
+            //
+          }
+          catch (const process_error& e)
+          {
+            error << "unable to execute " << args[0] << ": " << e.what ();
+
+            if (e.child ())
+              exit (1);
+          }
+
+          throw failed ();
+        }
+      }
+
       void concurrent_runner::
       run (const test& t)
       {
-        // @@ TODO
-
         // @@ When running multiple threads will need to synchronize printing
         // the diagnostics so it don't overlap for concurrent tests.
         // Alternatively we can not bother with that and expect a user to
@@ -42,6 +271,182 @@ namespace build2
 
         if (verb >= 3)
           print_test (t);
+
+        // Pre-search the program path so it is reflected in the failure
+        // diagnostics. The user can see the original path running the test
+        // operation with the verbosity level > 2.
+        //
+        process_path pp (run_search (t.program, true));
+        cstrings args {pp.recall_string ()};
+
+        for (const auto& a: t.arguments)
+          args.push_back (a.c_str ());
+
+        args.push_back (nullptr);
+
+        // Normally while handling child process failures (IO errors, non-zero
+        // exit status) we suppress the diagnostics supposing that the child
+        // issues it's own one. While this is reasonable to expect from known
+        // production-quality programs here it can result in the absense of any
+        // diagnostics at all. Also the child stderr (and so diagnostics) can
+        // be redirected to /dev/null and not be available for the user. This
+        // why we will always issue the diagnostics despite the fact sometimes
+        // it can look redundant.
+        //
+        try
+        {
+          // For stdin 'none' redirect type we somehow need to make sure that
+          // the child process doesn't read from stdin. That is tricky to do in
+          // a portable way. Here we suppose that the program which
+          // (erroneously) tries to read some data from stdin being redirected
+          // to /dev/null fails not being able to do read expected data, and so
+          // the test doesn't pass through.
+          //
+          // @@ Obviously doesn't cover the case when the process reads
+          //    whatever available.
+          // @@ Another approach could be not to redirect stdin and let the
+          //    process to hang which can be interpreted as a test failure.
+          // @@ Both ways are quite ugly. Is there some better way to do this?
+          //
+          int in (t.in.type == redirect_type::null ||
+                  t.in.type == redirect_type::none
+                  ? -2
+                  : -1);
+
+          // Dealing with stdout and stderr redirect types other than 'null'
+          // using pipes is tricky in the general case. Going this path we
+          // would need to read both streams in a non-blocking manner which we
+          // can't (easily) do in a portable way. Using diff utility to get a
+          // nice-looking stream/pattern difference would complicate things
+          // further.
+          //
+          // So the approach is the following. Child standard stream are
+          // redirected to files. When the child exits and the exit status is
+          // validated we just sequentially compare each file content with the
+          // corresponding pattern. The positive side-effect of this approach
+          // is that the output of a faulty test command can be provided for
+          // troubleshooting.
+          //
+          stream_cache osc ("stdout");
+          int out (t.out.type == redirect_type::null ? -2 : osc.wopen ());
+
+          stream_cache esc ("stderr");
+          int err (t.err.type == redirect_type::null ? -2 : esc.wopen ());
+
+          if (verb >= 2)
+            print_process (args);
+
+          process pr (pp, args.data (), in, out, err);
+
+          try
+          {
+            osc.close ();
+            esc.close ();
+
+            if (t.in.type == redirect_type::here_string ||
+                t.in.type == redirect_type::here_document)
+            {
+              ofdstream os (pr.out_fd);
+              os << t.in.value;
+
+              // Here-document is always endline-terminated.
+              //
+              if (t.in.type == redirect_type::here_string)
+                os << endl;
+
+              os.close ();
+            }
+
+            // Just wait. The program failure can mean the test success.
+            //
+            pr.wait ();
+
+            // Check if the process terminated normally and obtain the status
+            // if that's the case.
+            //
+            bool abnorm;
+            process::status_type status;
+
+            // @@ Shouldn't we incorporate means for checking for abnormal
+            //    termination and getting the real exit status into
+            //    libbutl::process?
+            //
+#ifndef _WIN32
+            abnorm = !WIFEXITED (pr.status);
+            status = abnorm ? 1 : WEXITSTATUS (pr.status);
+#else
+            // @@ Is there a reliable way to detect if the process terminated
+            //    abnormally on Windows?
+            //
+            abnorm = false;
+            status = pr.status;
+#endif
+            bool valid_status (!abnorm && status >= 0 && status < 256);
+
+            bool eq (t.exit.comparison == exit_comparison::eq);
+
+            bool correct_status (valid_status &&
+                                 (status == t.exit.status) == eq);
+
+            // If there is no correct exit status by whatever reason then dump
+            // stderr (if cached), keep both stdout and stderr (those which
+            // are cached) for troubleshooting, and finally fail.
+            //
+            if (!correct_status)
+            {
+              if (esc.exists () && esc.ropen ())
+                cerr << esc.rdbuf ();
+
+              // Keep non-empty cache files and fail with a proper diagnostics.
+              //
+              diag_record d (fail);
+
+              if (abnorm)
+                d << pp << " terminated abnormally";
+              else if (!valid_status)
+                d << pp << " exit status " << status << " is invalid" <<
+                  info << "must be an unsigned integer < 256";
+              else if (!correct_status)
+                d << pp << " exit status " << status
+                  << (eq ? " != " : " == ") << (int)t.exit.status;
+              else
+                assert (false);
+
+              auto keep_stream = [&d] (stream_cache& sc)
+              {
+                if (sc.exists () && sc.ropen ())
+                {
+                  sc.cleanup.cancel ();
+                  d << info << sc.name << " is saved to " << sc.path;
+                }
+              };
+
+              keep_stream (osc);
+              keep_stream (esc);
+            }
+
+            check_output (pp, osc, t.out);
+            check_output (pp, esc, t.err);
+          }
+          catch (const io_error& e)
+          {
+            // Child exit status doesn't matter. Just wait for the process
+            // completion.
+            //
+            pr.wait (); // Check throw.
+
+            fail << "IO operation failed for " << pp << ": " << e.what ();
+          }
+        }
+        catch (const process_error& e)
+        {
+          error << "unable to execute " << pp << ": " << e.what ();
+
+          if (e.child ())
+            exit (1);
+
+          throw failed ();
+        }
       }
     }
   }
diff --git a/build2/test/script/script b/build2/test/script/script
index 04b964f..236b025 100644
--- a/build2/test/script/script
+++ b/build2/test/script/script
@@ -97,6 +97,13 @@ namespace build2
         //
         exit_comparison comparison = exit_comparison::eq;
         uint8_t status = 0;
+
+        // Required by VC which fails to initialize as aggregate a class with
+        // default member initializers.
+        //
+        command_exit () = default;
+        command_exit (exit_comparison c, uint8_t s)
+            : comparison (c), status (s) {}
       };
 
       struct test: command