Add dry-run support to install/uninstall rules

4 files changed, 82 insertions, 64 deletions

diff --git a/build2/filesystem.hxx b/build2/filesystem.hxx
index 2044141..91ee418 100644
--- a/build2/filesystem.hxx
+++ b/build2/filesystem.hxx
@@ -15,7 +15,7 @@
 // Compared to the libbutl's versions, these handle errors and issue
 // diagnostics. Some of them also print the corresponding command line
 // equivalent at the specified verbosity level. Note that most of such
-// functions also handle the dry_run flag.
+// functions also respect the dry_run flag.
 //
 namespace build2
 {
diff --git a/build2/install/rule.cxx b/build2/install/rule.cxx
index a30cbd3..85bd501 100644
--- a/build2/install/rule.cxx
+++ b/build2/install/rule.cxx
@@ -690,15 +690,25 @@ namespace build2
 
     // install -d <dir>
     //
-    // If verbose is false, then only print the command at verbosity level 2
-    // or higher.
-    //
     static void
     install_d (const scope& rs,
                const install_dir& base,
                const dir_path& d,
                bool verbose = true)
     {
+      // Here is the problem: if this is a dry-run, then we will keep showing
+      // the same directory creation commands over and over again (because we
+      // don't actually create them). There are two alternative ways to solve
+      // this: actually create the directories or simply don't show anything.
+      // While we use the former approach during update (see mkdir() in
+      // filesystem), here it feels like we really shouldn't be touching the
+      // destination filesystem. Plus, not showing anything will be symmetric
+      // with uninstall since the directories won't be empty (because we don't
+      // actually uninstall any files).
+      //
+      if (dry_run)
+        return;
+
       dir_path chd (chroot_path (rs, d));
 
       try
@@ -760,9 +770,6 @@ namespace build2
     // install <file> <dir>/
     // install <file> <file>
     //
-    // If verbose is false, then only print the command at verbosity level 2
-    // or higher.
-    //
     static void
     install_f (const scope& rs,
                const install_dir& base,
@@ -809,7 +816,8 @@ namespace build2
       else if (verb && verbose)
         text << "install " << t;
 
-      run (pp, args);
+      if (!dry_run)
+        run (pp, args);
     }
 
     void file_rule::
@@ -844,7 +852,8 @@ namespace build2
       else if (verb && verbose)
         text << "install " << rell << " -> " << target;
 
-      run (pp, args);
+      if (!dry_run)
+        run (pp, args);
     }
 
     target_state file_rule::
@@ -952,15 +961,17 @@ namespace build2
     // itself unless base == dir. Return false if nothing has been removed
     // (i.e., the directories do not exist or are not empty).
     //
-    // If verbose is false, then only print the command at verbosity level 2
-    // or higher.
-    //
     static bool
     uninstall_d (const scope& rs,
                  const install_dir& base,
                  const dir_path& d,
                  bool verbose)
     {
+      // See install_d() for the rationale.
+      //
+      if (dry_run)
+        return false;
+
       dir_path chd (chroot_path (rs, d));
 
       // Figure out if we should try to remove this directory. Note that if
@@ -1086,13 +1097,16 @@ namespace build2
         if (verb >= 2)
           text << "rm " << relf;
 
-        try
+        if (!dry_run)
         {
-          try_rmfile (f);
-        }
-        catch (const system_error& e)
-        {
-          fail << "unable to remove file " << f << ": " << e;
+          try
+          {
+            try_rmfile (f);
+          }
+          catch (const system_error& e)
+          {
+            fail << "unable to remove file " << f << ": " << e;
+          }
         }
       }
       else
@@ -1112,7 +1126,8 @@ namespace build2
         if (verb >= 2)
           print_process (args);
 
-        run (pp, args);
+        if (!dry_run)
+          run (pp, args);
       }
 
       return true;
diff --git a/build2/install/rule.hxx b/build2/install/rule.hxx
index ec4b9bf..526683d 100644
--- a/build2/install/rule.hxx
+++ b/build2/install/rule.hxx
@@ -154,7 +154,7 @@ namespace build2
       // Installation/uninstallation "commands".
       //
       // If verbose is false, then only print the command at verbosity level 2
-      // or higher.
+      // or higher. Note that these functions respect the dry_run flag.
 
       // Install a symlink: base/link -> target.
       //
diff --git a/build2/version/utility.cxx b/build2/version/utility.cxx
index 4222fff..6c4d43e 100644
--- a/build2/version/utility.cxx
+++ b/build2/version/utility.cxx
@@ -18,61 +18,64 @@ namespace build2
     auto_rmfile
     fixup_manifest (const path& in, path out, const standard_version& v)
     {
-      auto_rmfile r (move (out));
+      auto_rmfile r (move (out), !dry_run /* active */);
 
-      try
+      if (!dry_run)
       {
-        permissions perm (path_permissions (in));
-
-        ifdstream ifs (in);
-        manifest_parser p (ifs, in.string ());
+        try
+        {
+          permissions perm (path_permissions (in));
 
-        auto_fd ofd (fdopen (r.path,
-                             fdopen_mode::out       |
-                             fdopen_mode::create    |
-                             fdopen_mode::exclusive |
-                             fdopen_mode::binary,
-                             perm));
+          ifdstream ifs (in);
+          manifest_parser p (ifs, in.string ());
 
-        ofdstream ofs (move (ofd));
-        manifest_serializer s (ofs, r.path.string ());
+          auto_fd ofd (fdopen (r.path,
+                               fdopen_mode::out       |
+                               fdopen_mode::create    |
+                               fdopen_mode::exclusive |
+                               fdopen_mode::binary,
+                               perm));
 
-        manifest_name_value nv (p.next ());
-        assert (nv.name.empty () && nv.value == "1"); // We just loaded it.
-        s.next (nv.name, nv.value);
-
-        for (nv = p.next (); !nv.empty (); nv = p.next ())
-        {
-          if (nv.name == "version")
-            nv.value = v.string ();
+          ofdstream ofs (move (ofd));
+          manifest_serializer s (ofs, r.path.string ());
 
+          manifest_name_value nv (p.next ());
+          assert (nv.name.empty () && nv.value == "1"); // We just loaded it.
           s.next (nv.name, nv.value);
-        }
 
-        s.next (nv.name, nv.value); // End of manifest.
-        s.next (nv.name, nv.value); // End of stream.
+          for (nv = p.next (); !nv.empty (); nv = p.next ())
+          {
+            if (nv.name == "version")
+              nv.value = v.string ();
 
-        ofs.close ();
-        ifs.close ();
+            s.next (nv.name, nv.value);
+          }
 
-        return r;
-      }
-      catch (const manifest_parsing& e)
-      {
-        location l (&in, e.line, e.column);
-        fail (l) << e.description << endf;
-      }
-      catch (const manifest_serialization& e)
-      {
-        location l (&r.path);
-        fail (l) << e.description << endf;
-      }
-      catch (const io_error& e)
-      {
-        fail << "io error: " << e <<
-          info << "while reading " << in <<
-          info << "while writing " << r.path << endf;
+          s.next (nv.name, nv.value); // End of manifest.
+          s.next (nv.name, nv.value); // End of stream.
+
+          ofs.close ();
+          ifs.close ();
+        }
+        catch (const manifest_parsing& e)
+        {
+          location l (&in, e.line, e.column);
+          fail (l) << e.description;
+        }
+        catch (const manifest_serialization& e)
+        {
+          location l (&r.path);
+          fail (l) << e.description;
+        }
+        catch (const io_error& e)
+        {
+          fail << "io error: " << e <<
+            info << "while reading " << in <<
+            info << "while writing " << r.path;
+        }
       }
+
+      return r;
     }
   }
 }