Add --cwd|-t option to env pseudo-builtin

5 files changed, 87 insertions, 17 deletions

diff --git a/libbuild2/script/parser.cxx b/libbuild2/script/parser.cxx
index ebfd5fc..f234d58 100644
--- a/libbuild2/script/parser.cxx
+++ b/libbuild2/script/parser.cxx
@@ -1028,8 +1028,9 @@ namespace build2
             if (prog && tt == type::word && t.value == "env")
             {
               parsed_env r (parse_env_builtin (t, tt));
+              c.cwd       = move (r.cwd);
               c.variables = move (r.variables);
-              c.timeout = r.timeout;
+              c.timeout   = r.timeout;
               env = true;
             }
 
@@ -1411,10 +1412,16 @@ namespace build2
           return r;
         };
 
+        auto bad = [&i, &o, this] (const string& v)
+        {
+          fail (i->second) << "env: invalid value '" << v << "' for option '"
+                           << o << "'";
+        };
+
         // As above but convert the option value to a number and fail on
         // error.
         //
-        auto num = [&i, &o, &str, this] (const char* ln, const char* sn)
+        auto num = [&str, &bad] (const char* ln, const char* sn)
         {
           optional<uint64_t> r;
           if (optional<string> s = str (ln, sn))
@@ -1422,8 +1429,29 @@ namespace build2
             r = parse_number (*s);
 
             if (!r)
-              fail (i->second) << "env: invalid value '" << *s
-                               << "' for option '" << o << "'";
+              bad (*s);
+          }
+
+          return r;
+        };
+
+        // As above but convert the option value to a directory path and fail
+        // on error.
+        //
+        auto dir = [&str, &bad] (const char* ln, const char* sn)
+        {
+          optional<dir_path> r;
+          if (optional<string> s = str (ln, sn))
+          try
+          {
+            // Note that we don't need to check that the path is not empty,
+            // since str() fails for empty values.
+            //
+            r = dir_path (move (*s));
+          }
+          catch (const invalid_path& e)
+          {
+            bad (e.path);
           }
 
           return r;
@@ -1435,6 +1463,10 @@ namespace build2
         {
           r.timeout = chrono::seconds (*v);
         }
+        else if (optional<dir_path> v = dir ("--cwd", "-c"))
+        {
+          r.cwd = move (*v);
+        }
         else if (optional<string> v = str ("--unset", "-u"))
         {
           verify_environment_var_name (*v, "env: ", i->second, o.c_str ());
diff --git a/libbuild2/script/parser.hxx b/libbuild2/script/parser.hxx
index 9098b3c..2a10311 100644
--- a/libbuild2/script/parser.hxx
+++ b/libbuild2/script/parser.hxx
@@ -130,15 +130,16 @@ namespace build2
       pre_parse_line_start (token&, token_type&, lexer_mode);
 
       // Parse the env pseudo-builtin arguments up to the program name. Return
-      // the program execution timeout, the list of the variables that should
-      // be unset ("name") and/or set ("name=value") in the command
+      // the program execution timeout, CWD, the list of the variables that
+      // should be unset ("name") and/or set ("name=value") in the command
       // environment, and the token/type that starts the program name. Note
       // that the variable unsets come first, if present.
       //
       struct parsed_env
       {
         optional<duration> timeout;
-        environment_vars variables;
+        optional<dir_path> cwd;
+        environment_vars   variables;
       };
 
       parsed_env
diff --git a/libbuild2/script/run.cxx b/libbuild2/script/run.cxx
index 91fc9ac..f3b5cad 100644
--- a/libbuild2/script/run.cxx
+++ b/libbuild2/script/run.cxx
@@ -1227,6 +1227,8 @@ namespace build2
       //
       const command& c (*bc);
 
+      const dir_path& wdir (*env.work_dir.path);
+
       // Register the command explicit cleanups. Verify that the path being
       // cleaned up is a sub-path of the script working directory. Fail if
       // this is not the case.
@@ -1234,7 +1236,7 @@ namespace build2
       for (const auto& cl: c.cleanups)
       {
         const path& p (cl.path);
-        path np (normalize (p, *env.work_dir.path, ll));
+        path np (normalize (p, wdir, ll));
 
         const string& ls (np.leaf ().string ());
         bool wc (ls == "*" || ls == "**" || ls == "***");
@@ -1320,6 +1322,10 @@ namespace build2
         if (!first || !last)
           fail (ll) << program << " builtin must be the only pipe command";
 
+        if (c.cwd)
+          fail (ll) << "current working directory cannot be specified for "
+                    << program << " builtin";
+
         if (!c.variables.empty ())
           fail (ll) << "environment variables cannot be (un)set for "
                     << program << " builtin";
@@ -1455,7 +1461,7 @@ namespace build2
           }
         case redirect_type::file:
           {
-            isp = normalize (in.file.path, *env.work_dir.path, ll);
+            isp = normalize (in.file.path, wdir, ll);
 
             open_stdin ();
             break;
@@ -1549,9 +1555,9 @@ namespace build2
       // or null-device descriptor for merge, pass or null redirects
       // respectively (not opening any file).
       //
-      auto open = [&env, &ll, &std_path] (const redirect& r,
-                                          int dfd,
-                                          path& p) -> auto_fd
+      auto open = [&env, &wdir, &ll, &std_path] (const redirect& r,
+                                                 int dfd,
+                                                 path& p) -> auto_fd
       {
         assert (dfd == 1 || dfd == 2);
         const char* what (dfd == 1 ? "stdout" : "stderr");
@@ -1592,7 +1598,7 @@ namespace build2
             //
             p = r.file.mode == redirect_fmode::compare
               ? std_path (what)
-              : normalize (r.file.path, *env.work_dir.path, ll);
+              : normalize (r.file.path, wdir, ll);
 
             m |= r.file.mode == redirect_fmode::append
               ? fdopen_mode::at_end
@@ -1810,6 +1816,28 @@ namespace build2
         }
       };
 
+      // Derive the process/builtin CWD.
+      //
+      // If the process/builtin CWD is specified via the env pseudo-builtin,
+      // then use that, completing it relative to the script environment work
+      // directory, if it is relative. Otherwise, use the script environment
+      // work directory.
+      //
+      dir_path completed_cwd;
+      if (c.cwd && c.cwd->relative ())
+        completed_cwd = wdir / *c.cwd;
+
+      const dir_path& cwd (!completed_cwd.empty () ? completed_cwd :
+                           c.cwd                   ? *c.cwd        :
+                                                     wdir);
+
+      // Unless CWD is the script environment work directory (which always
+      // exists), verify that it exists and fail if it doesn't.
+      //
+      if (&cwd != &wdir && !exists (cwd))
+        fail (ll) << "specified working directory " << cwd
+                  << " does not exist";
+
       // Absent if the process/builtin misses the "unsuccessful" deadline.
       //
       optional<process_exit> exit;
@@ -2069,7 +2097,7 @@ namespace build2
           builtin b (bi->function (r,
                                    c.arguments,
                                    move (ifd), move (ofd.out), move (efd),
-                                   *env.work_dir.path,
+                                   cwd,
                                    bcs));
 
           pipe_command pc (b, c, ll, prev_cmd);
@@ -2159,7 +2187,7 @@ namespace build2
                 program (path (s, 1, s.size () - 1));
             }
             else
-              program (*env.work_dir.path / p);
+              program (wdir / p);
           }
         }
         catch (const invalid_path& e)
@@ -2189,7 +2217,7 @@ namespace build2
             *pe.path,
             args.data (),
             {ifd.get (), -1}, process::pipe (ofd), {-1, efd.get ()},
-            env.work_dir.path->string ().c_str (),
+            cwd.string ().c_str (),
             pe.vars);
 
           // Can't throw.
diff --git a/libbuild2/script/script.cxx b/libbuild2/script/script.cxx
index 298d71f..9e6eeed 100644
--- a/libbuild2/script/script.cxx
+++ b/libbuild2/script/script.cxx
@@ -411,7 +411,7 @@ namespace build2
       {
         // Print the env builtin if any of its options/arguments are present.
         //
-        if (!c.variables.empty () || c.timeout)
+        if (c.timeout || c.cwd || !c.variables.empty ())
         {
           o << "env";
 
@@ -421,6 +421,14 @@ namespace build2
             o << " -t "
               << chrono::duration_cast<chrono::seconds> (*c.timeout).count ();
 
+          // CWD.
+          //
+          if (c.cwd)
+          {
+            o << " -c ";
+            print_path (*c.cwd);
+          }
+
           // Variable unsets/sets.
           //
           auto b (c.variables.begin ()), i (b), e (c.variables.end ());
diff --git a/libbuild2/script/script.hxx b/libbuild2/script/script.hxx
index dd31e33..d162900 100644
--- a/libbuild2/script/script.hxx
+++ b/libbuild2/script/script.hxx
@@ -324,6 +324,7 @@ namespace build2
       process_path program;
 
       strings            arguments;
+      optional<dir_path> cwd;       // From env builtin.
       environment_vars   variables; // From env builtin.
       optional<duration> timeout;   // From env builtin.