Added a new source_context function

src/error.cc

@@ -77,4 +77,40 @@ string line_context(const string& line,
   return buf.str();
 }
 
+string source_context(const path&   file,
+		      std::size_t   pos,
+		      std::size_t   end_pos,
+		      const string& prefix)
+{
+  std::size_t len = end_pos - pos;
+  if (! len)
+    return _("<no source context>");
+
+  assert(len > 0);
+  assert(len < 2048);
+
+  std::ostringstream out;
+      
+  ifstream in(file);
+  in.seekg(pos, std::ios::beg);
+      
+  scoped_array<char> buf(new char[len + 1]);
+  in.read(buf.get(), len);
+  assert(static_cast<std::size_t>(in.gcount()) == len);
+  buf[len] = '\0';
+
+  bool first = true;
+  for (char * p = std::strtok(buf.get(), "\n");
+       p;
+       p = std::strtok(NULL, "\n")) {
+    if (first)
+      first = false;
+    else
+      out << '\n';
+    out << prefix << p;
+  }
+
+  return out.str();
+}
+
 } // namespace ledger

src/error.h

@@ -81,6 +81,11 @@ string line_context(const string& line,
 		    std::size_t	  pos     = 0,
 		    std::size_t	  end_pos = 0);
 
+string source_context(const path&   file,
+		      std::size_t   pos,
+		      std::size_t   end_pos,
+		      const string& prefix = "");
+
 #define DECLARE_EXCEPTION(name, kind)				\
   class name : public kind {					\
   public:							\

src/item.cc

@@ -367,30 +367,9 @@ bool item_t::valid() const
   return true;
 }
 
-void print_item(std::ostream& out,
+void print_item(std::ostream& out, const item_t& item, const string& prefix)
-		const item_t& item,
-		const string& prefix)
 {
-  std::size_t len = item.end_pos - item.beg_pos;
+  out << source_context(item.pathname, item.beg_pos, item.end_pos, prefix);
-
-  ifstream in(item.pathname);
-  in.seekg(item.beg_pos, std::ios::beg);
-      
-  scoped_array<char> buf(new char[len + 1]);
-  in.read(buf.get(), len);
-  assert(static_cast<std::size_t>(in.gcount()) == len);
-  buf[len] = '\0';
-
-  bool first = true;
-  for (char * p = std::strtok(buf.get(), "\n");
-       p;
-       p = std::strtok(NULL, "\n")) {
-    if (first)
-      first = false;
-    else
-      out << '\n';
-    out << prefix << p;
-  }
 }
 
 string item_context(const item_t& item, const string& desc)