[2/4] Save plain text in the source cache

diff --git a/gdb/source-cache.c b/gdb/source-cache.c
index f0cb6b80059..0cc2076258c 100644
--- a/gdb/source-cache.c
+++ b/gdb/source-cache.c
@@ -31,7 +31,6 @@ 
    when GDB is linked.  Happens, e.g., in the MinGW build.  */
 #undef open
 #undef close
-#include <fstream>
 #include <sstream>
 #include <srchilite/sourcehighlight.h>
 #include <srchilite/langmap.h>
@@ -48,33 +47,19 @@  source_cache g_source_cache;
 /* See source-cache.h.  */
 
 bool
-source_cache::get_plain_source_lines (struct symtab *s, int first_line,
-				      int last_line, std::string *lines)
+source_cache::get_plain_source_lines (struct symtab *s, std::string *lines)
 {
   scoped_fd desc (open_source_file_with_line_charpos (s));
   if (desc.get () < 0)
     return false;
 
-  if (first_line < 1 || first_line > s->nlines || last_line < 1)
-    return false;
+  struct stat st;
 
-  if (lseek (desc.get (), s->line_charpos[first_line - 1], SEEK_SET) < 0)
+  if (fstat (desc.get (), &st) < 0)
     perror_with_name (symtab_to_filename_for_display (s));
 
-  int last_charpos;
-  if (last_line >= s->nlines)
-    {
-      struct stat st;
-
-      if (fstat (desc.get (), &st) < 0)
-	perror_with_name (symtab_to_filename_for_display (s));
-      /* We could cache this in line_charpos... */
-      last_charpos = st.st_size;
-    }
-  else
-    last_charpos = s->line_charpos[last_line];
-
-  lines->resize (last_charpos - s->line_charpos[first_line - 1]);
+  /* We could cache this in line_charpos... */
+  lines->resize (st.st_size);
   if (myread (desc.get (), &(*lines)[0], lines->size ()) < 0)
     perror_with_name (symtab_to_filename_for_display (s));
 
@@ -182,70 +167,57 @@  source_cache::get_source_lines (struct symtab *s, int first_line,
   if (first_line < 1 || last_line < 1 || first_line > last_line)
     return false;
 
-#ifdef HAVE_SOURCE_HIGHLIGHT
-  if (source_styling && gdb_stdout->can_emit_style_escape ())
-    {
-      const char *fullname = symtab_to_fullname (s);
+  std::string fullname = symtab_to_fullname (s);
 
-      for (const auto &item : m_source_map)
+  for (const auto &item : m_source_map)
+    {
+      if (item.fullname == fullname)
 	{
-	  if (item.fullname == fullname)
-	    {
-	      *lines = extract_lines (item.contents, first_line, last_line);
-	      return true;
-	    }
+	  *lines = extract_lines (item.contents, first_line, last_line);
+	  return true;
 	}
+    }
 
+  std::string contents;
+  if (!get_plain_source_lines (s, &contents))
+    return false;
+
+#ifdef HAVE_SOURCE_HIGHLIGHT
+  if (source_styling && gdb_stdout->can_emit_style_escape ())
+    {
       const char *lang_name = get_language_name (SYMTAB_LANGUAGE (s));
       if (lang_name != nullptr)
 	{
-	  std::ifstream input (fullname);
-	  if (input.is_open ())
+	  /* The global source highlight object, or null if one was
+	     never constructed.  This is stored here rather than in
+	     the class so that we don't need to include anything or do
+	     conditional compilation in source-cache.h.  */
+	  static srchilite::SourceHighlight *highlighter;
+
+	  if (highlighter == nullptr)
 	    {
-	      /* The global source highlight object, or null if one
-		 was never constructed.  This is stored here rather
-		 than in the class so that we don't need to include
-		 anything or do conditional compilation in
-		 source-cache.h.  */
-	      static srchilite::SourceHighlight *highlighter;
-
-	      if (s->line_charpos == 0)
-		{
-		  scoped_fd desc (open_source_file_with_line_charpos (s));
-		  if (desc.get () < 0)
-		    return false;
-
-		  /* FULLNAME points to a value owned by the symtab
-		     (symtab::fullname).  Calling open_source_file reallocates
-		     that value, so we must refresh FULLNAME to avoid a
-		     use-after-free.  */
-		  fullname = symtab_to_fullname (s);
-		}
-
-	      if (highlighter == nullptr)
-		{
-		  highlighter = new srchilite::SourceHighlight ("esc.outlang");
-		  highlighter->setStyleFile ("esc.style");
-		}
-
-	      std::ostringstream output;
-	      highlighter->highlight (input, output, lang_name, fullname);
-
-	      source_text result = { fullname, output.str () };
-	      m_source_map.push_back (std::move (result));
-
-	      if (m_source_map.size () > MAX_ENTRIES)
-		m_source_map.erase (m_source_map.begin ());
-
-	      *lines = extract_lines (m_source_map.back ().contents,
-				      first_line, last_line);
-	      return true;
+	      highlighter = new srchilite::SourceHighlight ("esc.outlang");
+	      highlighter->setStyleFile ("esc.style");
 	    }
+
+	  std::istringstream input (contents);
+	  std::ostringstream output;
+	  highlighter->highlight (input, output, lang_name, fullname);
+
+	  contents = output.str ();
 	}
     }
 #endif /* HAVE_SOURCE_HIGHLIGHT */
 
-  return get_plain_source_lines (s, first_line, last_line, lines);
+  source_text result = { std::move (fullname), std::move (contents) };
+  m_source_map.push_back (std::move (result));
+
+  if (m_source_map.size () > MAX_ENTRIES)
+    m_source_map.erase (m_source_map.begin ());
+
+  *lines = extract_lines (m_source_map.back ().contents,
+			  first_line, last_line);
+  return true;
 }
 
 #if GDB_SELF_TEST
diff --git a/gdb/source-cache.h b/gdb/source-cache.h
index a00efbf3fba..0c8b14e483e 100644
--- a/gdb/source-cache.h
+++ b/gdb/source-cache.h
@@ -58,11 +58,10 @@  private:
     std::string contents;
   };
 
-  /* A helper function for get_source_lines that is used when the
-     source lines are not highlighted.  The arguments and return value
-     are as for get_source_lines.  */
-  bool get_plain_source_lines (struct symtab *s, int first_line,
-			       int last_line, std::string *lines_out);
+  /* A helper function for get_source_lines reads a source file.
+     Returns false on error.  If no error, the contents of the file
+     are put into *LINES_OUT, and returns true.  */
+  bool get_plain_source_lines (struct symtab *s, std::string *lines_out);
 
   /* The contents of the cache.  */
   std::vector<source_text> m_source_map;