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

5 files changed, 203 insertions, 19 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"
+    }
+  }
+}
diff --git a/tests/path-entry/driver.cxx b/tests/path-entry/driver.cxx
index 51ac04d..30aae92 100644
--- a/tests/path-entry/driver.cxx
+++ b/tests/path-entry/driver.cxx
@@ -18,12 +18,14 @@ import std.core;
 import std.io;
 #endif
 import butl.path;
+import butl.path-io;
 import butl.utility;    // operator<<(ostream, exception)
 import butl.optional;
 import butl.timestamp;
 import butl.filesystem;
 #else
 #include <libbutl/path.mxx>
+#include <libbutl/path-io.mxx>
 #include <libbutl/utility.mxx>
 #include <libbutl/optional.mxx>
 #include <libbutl/timestamp.mxx>
@@ -36,11 +38,12 @@ using namespace butl;
 // Usage: argv[0] [-l] [-t] [-p <permissions>] [-m <time>] [-a <time>] <path>
 //
 // If path entry exists then optionally modify its meta-information and print
-// its type, size (meaningful for the regular file only), permissions,
-// modification and access times to STDOUT, one value per line, and exit with
+// its type, size (meaningful for the regular file only), target path if the
+// specified entry is a symlink and its path otherwise, permissions,
+// modification and access times to stdout, one value per line, and exit with
 // the zero code. Otherwise exit with the one code. Don't follow symlink by
-// default. On failure print the error description to STDERR and exit with
-// the two code.
+// default. On failure print the error description to stderr and exit with the
+// two code.
 //
 // -l
 //    Follow symlinks.
@@ -136,6 +139,10 @@ main (int argc, const char* argv[])
     if (!es.first)
       return 1;
 
+    stage = "lstat entry";
+    pair<bool, entry_stat> ls (path_entry (p));
+    assert (ls.first);
+
     // The entry is a directory with a symlink followed.
     //
     bool tdir;
@@ -188,7 +195,6 @@ main (int argc, const char* argv[])
     }
 
     cout << "type: ";
-
     switch (es.second.type)
     {
     case entry_type::unknown:   cout << "unknown"; break;
@@ -197,13 +203,18 @@ main (int argc, const char* argv[])
     case entry_type::symlink:   cout << "symlink"; break;
     case entry_type::other:     cout << "other"; break;
     }
+    cout << endl;
+
+    cout << "size: " << es.second.size << endl
+         << "target: "
+         << (ls.second.type == entry_type::symlink
+             ? readsymlink (p)
+             : p) << endl;
 
     stage = "get permissions";
 
-    cout << endl
-         << "size: " << es.second.size << endl
-         << "permissions: " << oct
-         << static_cast<size_t> (path_permissions (p)) << endl;
+    cout << "permissions: "
+         << oct << static_cast<size_t> (path_permissions (p)) << endl;
 
     stage = tdir ? "get directory times" : "get file times";
 
diff --git a/tests/path-entry/testscript b/tests/path-entry/testscript
index 0424dff..1d6911f 100644
--- a/tests/path-entry/testscript
+++ b/tests/path-entry/testscript
@@ -12,10 +12,10 @@
   :
   {
     cat <:'abc' >=f;
-    $* f >>~/EOO/
+    $* f >>~%EOO%
       type: regular
       size: 3
-      /.+
+      %.+
       EOO
   }
 
@@ -25,9 +25,9 @@
   :
   {
     mkdir -p d;
-    $* d >>~/EOO/
+    $* d >>~%EOO%
       type: directory
-      /.+
+      %.+
       EOO
   }
 
@@ -36,10 +36,10 @@
   {
     cat <:'abc' >=f;
     ln -s f l;
-    $* -l l >>~/EOO/
+    $* -l l >>~%EOO%
       type: regular
       size: 3
-      /.+
+      %.+
       EOO
   }
 
@@ -54,7 +54,7 @@
   if ($test.target == $build.host)
   {
     +if ($cxx.target.class != 'windows')
-      lnf = ln -s t l &l
+      lnf = ^ln -s t l &l
       lnd = $lnf
     else
       echo 'yes' >=t
@@ -156,7 +156,12 @@
       {
         mkdir t;
         $jnc;
-        $* -p 400 -m '2020-03-05 00:00:00' -a '2020-03-05 00:00:01' t | set ti;
+
+        # Pass the absolute path so the junction's target path matches.
+        #
+        $* -p 400 -m '2020-03-05 00:00:00' -a '2020-03-05 00:00:01' $~/t | \
+        set ti;
+
         $* -l l >"$ti"
       }