Add readsymlink(), followsymlink(), and try_followsymlink()

3 files changed, 170 insertions, 2 deletions

diff --git a/tests/link/buildfile b/tests/link/buildfile
index 462f60d..9b108b0 100644
--- a/tests/link/buildfile
+++ b/tests/link/buildfile
@@ -3,4 +3,4 @@
 
 import libs = libbutl%lib{butl}
 
-exe{driver}: {hxx cxx}{*} $libs
+exe{driver}: {hxx cxx}{*} $libs testscript
diff --git a/tests/link/driver.cxx b/tests/link/driver.cxx
index a77df6f..231da4b 100644
--- a/tests/link/driver.cxx
+++ b/tests/link/driver.cxx
@@ -53,6 +53,12 @@ link_file (const path& target, const path& link, mklink ml, bool check_content)
     case mklink::hard: mkhardlink (target, link);                  break;
     case mklink::any:  mkanylink  (target, link, true /* copy */); break;
     }
+
+    pair<bool, entry_stat> es (path_entry (link));
+    assert (es.first);
+
+    if (es.second.type == entry_type::symlink && readsymlink (link) != target)
+      return false;
   }
   catch (const system_error&)
   {
@@ -87,6 +93,12 @@ link_dir (const dir_path& target,
       mkhardlink (target, link);
     else
       mksymlink (target, link);
+
+    pair<bool, entry_stat> es (path_entry (link));
+    assert (es.first);
+
+    if (es.second.type == entry_type::symlink)
+      readsymlink (link); // // Check for errors.
   }
   catch (const system_error&)
   {
@@ -120,9 +132,86 @@ link_dir (const dir_path& target,
   return te == le;
 }
 
+// Usages:
+//
+// argv[0]
+// argv[0] -s <target> <link>
+// argv[0] -f <path>
+//
+// In the first form run the basic symbolic and hard link tests.
+//
+// In the second form create a symlink. On error print the diagnostics to
+// stderr and exit with the one code.
+//
+// In the third form follow symlinks and print the resulting target path to
+// stdout. On error print the diagnostics to stderr and exit with the one
+// code.
+//
 int
-main ()
+main (int argc, const char* argv[])
 {
+  bool create_symlink  (false);
+  bool follow_symlinks (false);
+
+  int i (1);
+  for (; i != argc; ++i)
+  {
+    string v (argv[i]);
+
+    if (v == "-s")
+      create_symlink = true;
+    else if (v == "-f")
+      follow_symlinks = true;
+    else
+      break;
+  }
+
+  if (create_symlink)
+  {
+    assert (!follow_symlinks);
+    assert (i + 2 == argc);
+
+    try
+    {
+      path t (argv[i]);
+      path l (argv[i + 1]);
+
+      bool dir (dir_exists (t.relative () ? l.directory () / t : t));
+      mksymlink (t, l, dir);
+
+      path lt (readsymlink (l));
+
+      // The targets may only differ for Windows directory junctions.
+      //
+      assert (lt == t || dir);
+
+      return 0;
+    }
+    catch (const system_error& e)
+    {
+      cerr << "error: " << e << endl;
+      return 1;
+    }
+  }
+  else if (follow_symlinks)
+  {
+    assert (!create_symlink);
+    assert (i + 1 == argc);
+
+    try
+    {
+      cout << try_followsymlink (path (argv[i])).first << endl;
+      return 0;
+    }
+    catch (const system_error& e)
+    {
+      cerr << "error: " << e << endl;
+      return 1;
+    }
+  }
+  else
+    assert (i == argc);
+
   dir_path td (dir_path::temp_directory () / dir_path ("butl-link"));
 
   // Recreate the temporary directory (that possibly exists from the previous
diff --git a/tests/link/testscript b/tests/link/testscript
new file mode 100644
index 0000000..194b093
--- /dev/null
+++ b/tests/link/testscript
@@ -0,0 +1,79 @@
+# file      : tests/link/testscript
+# license   : MIT; see accompanying LICENSE file
+
+: basics
+:
+$*
+
+: follow-symlinks
+:
+: Note that we may not be able to create symlinks on Windows and so test on
+: POSIX only. But that'is ok since the follow_symlinks() implementation is not
+: platform-specific.
+:
+if ($cxx.target.class != 'windows')
+{
+  : not-symlink
+  :
+  {
+    touch f;
+    $* -f f >f
+  }
+
+  : not-exists
+  :
+  {
+    $* -f f >f
+  }
+
+  : single-link
+  :
+  {
+    : absolute
+    :
+    {
+      $* -s $~/f l &l;
+      $* -f l >/"$~/f"
+    }
+
+    : relative
+    :
+    {
+      $* -s d/f l &l;
+      $* -f l >/'d/f'
+    }
+  }
+
+  : multiple-links
+  :
+  {
+    : relative-path
+    :
+    {
+      mkdir -p d1/d2;
+      $* -s ../d3/f d1/d2/l1 &d1/d2/l1;
+
+      $* -f d1/d2/l1                  >/'d1/d3/f';
+      $* -f ../relative-path/d1/d2/l1 >/'../relative-path/d1/d3/f';
+
+      mkdir d4;
+      $* -s ../d1/d2/l1 d4/l2 &d4/l2;
+
+      $* -f d4/l2    >/'d1/d3/f';
+      $* -f $~/d4/l2 >/"$~/d1/d3/f"
+    }
+
+    : absolute-path
+    :
+    {
+      mkdir -p d1/d2;
+      $* -s ../d3/f d1/d2/l1 &d1/d2/l1;
+
+      mkdir d4;
+      $* -s $~/d1/d2/l1 d4/l2 &d4/l2;
+
+      $* -f d4/l2    >/"$~/d1/d3/f";
+      $* -f $~/d4/l2 >/"$~/d1/d3/f"
+    }
+  }
+}