change handling of standard input

For `-f /dev/stdin`, the `pathname` of the parsing context will be empty
as for any other streamed input.

`instance_t::include_directive` did not work as expected for `-f /dev/stdin`
and relative file names. One would expect them to be relative to the current
directory rather than `/dev`.

This will lead to `While parsing file ""` messages. This could be
adjusted to read `While parsing standard input`, but maybe it's not
worth the special cases.

This commit also fixes bug 788: behaviour of source_context for '-f -'

3 files changed, 4 insertions, 4 deletions

diff --git a/src/error.cc b/src/error.cc
index 58339db7..8aa1d3d6 100644
--- a/src/error.cc
+++ b/src/error.cc
@@ -84,7 +84,7 @@ string source_context(const path&            file,
                       const string&          prefix)
 {
   const std::streamoff len = end_pos - pos;
-  if (! len || file == path("/dev/stdin"))
+  if (! len || file.empty())
     return _("<no source context>");
 
   assert(len > 0);
diff --git a/src/item.cc b/src/item.cc
index 362fac7f..4e2a487c 100644
--- a/src/item.cc
+++ b/src/item.cc
@@ -582,8 +582,8 @@ string item_context(const item_t& item, const string& desc)
 
   std::ostringstream out;
 
-  if (item.pos->pathname == path("/dev/stdin")) {
-    out << desc << _(" from standard input:");
+  if (item.pos->pathname.empty()) {
+    out << desc << _(" from streamed input:");
     return out.str();
   }
 
diff --git a/src/session.cc b/src/session.cc
index b6153203..f047a540 100644
--- a/src/session.cc
+++ b/src/session.cc
@@ -143,7 +143,7 @@ std::size_t session_t::read_data(const string& master_account)
     }
 
     foreach (const path& pathname, HANDLER(file_).data_files) {
-      if (pathname == "-") {
+      if (pathname == "-" || pathname == "/dev/stdin") {
         // To avoid problems with stdin and pipes, etc., we read the entire
         // file in beforehand into a memory buffer, and then parcel it out
         // from there.