gdb: introduce iterator_range, remove next_adapter

I was always a bit confused by next_adapter, because it kind of mixes
the element type and the iterator type.  In reality, it is not much more
than a class that wraps two iterators (begin and end).  However, it
assumes that:

 - you can construct the begin iterator by passing a pointer to the
   first element of the iterable
 - you can default-construct iterator to make the end iterator

I think that by generalizing it a little bit, we can re-use it at more
places.

Rename it to "iterator_range".  I think it describes a bit better: it's
a range made by wrapping a begin and end iterator.  Move it to its own
file, since it's not related to next_iterator anymore.

iterator_range has two constructors.  The variadic one, where arguments
are forwarded to construct the underlying begin iterator.  The end
iterator is constructed through default construction.  This is a
generalization of what we have today.

There is another constructor which receives already constructed begin
and end iterators, useful if the end iterator can't be obtained by
default-construction.  Or, if you wanted to make a range that does not
end at the end of the container, you could pass any iterator as the
"end".

This generalization allows removing some "range" classes, like
all_inferiors_range.  These classes existed only to pass some arguments
when constructing the begin iterator.  With iterator_range, those same
arguments are passed to the iterator_range constructed and then
forwarded to the constructed begin iterator.

There is a small functional difference in how iterator_range works
compared to next_adapter.  next_adapter stored the pointer it received
as argument and constructeur an iterator in the `begin` method.
iterator_range constructs the begin iterator and stores it as a member.
Its `begin` method returns a copy of that iterator.

With just iterator_range, uses of next_adapter<foo> would be replaced
with:

  using foo_iterator = next_iterator<foo>;
  using foo_range = iterator_range<foo_iterator>;

However, I added a `next_range` wrapper as a direct replacement for
next_adapter<foo>.  IMO, next_range is a slightly better name than
next_adapter.

The rest of the changes are applications of this new class.

gdbsupport/ChangeLog:

	* next-iterator.h (class next_adapter): Remove.
	* iterator-range.h: New.

gdb/ChangeLog:

	* breakpoint.h (bp_locations_range): Remove.
	(bp_location_range): New.
	(struct breakpoint) <locations>: Adjust type.
	(breakpoint_range): Use iterator_range.
	(tracepoint_range): Use iterator_range.
	* breakpoint.c (breakpoint::locations): Adjust return type.
	* gdb_bfd.h (gdb_bfd_section_range): Use iterator_range.
	* gdbthread.h (all_threads_safe): Pass argument to
	all_threads_safe_range.
	* inferior-iter.h (all_inferiors_range): Use iterator_range.
	(all_inferiors_safe_range): Use iterator_range.
	(all_non_exited_inferiors_range): Use iterator_range.
	* inferior.h (all_inferiors, all_non_exited_inferiors): Pass
	inferior_list as argument.
	* objfiles.h (struct objfile) <compunits_range>: Remove.
	<compunits>: Return compunit_symtab_range.
	* progspace.h (unwrapping_objfile_iterator)
	<unwrapping_objfile_iterator>: Take parameter by value.
	(unwrapping_objfile_range): Use iterator_range.
	(struct program_space) <objfiles_range>: Define with "using".
	<objfiles>: Adjust.
	<objfiles_safe_range>: Define with "using".
	<objfiles_safe>: Adjust.
	<solibs>: Return so_list_range, define here.
	* progspace.c (program_space::solibs): Remove.
	* psymtab.h (class psymtab_storage) <partial_symtab_iterator>:
	New.
	<partial_symtab_range>: Use iterator_range.
	* solist.h (so_list_range): New.
	* symtab.h (compunit_symtab_range):
	New.
	(symtab_range): New.
	(compunit_filetabs): Change to a function.
	* thread-iter.h (inf_threads_range,
	inf_non_exited_threads_range, safe_inf_threads_range,
	all_threads_safe_range): Use iterator_range.
	* top.h (ui_range): New.
	(all_uis): Use ui_range.

Change-Id: Ib7a9d2a3547f45f01aa1c6b24536ba159db9b854

1 files changed, 15 insertions, 30 deletions

diff --git a/gdb/progspace.h b/gdb/progspace.h
index 7906847..fb348ca 100644
--- a/gdb/progspace.h
+++ b/gdb/progspace.h
@@ -25,6 +25,7 @@
 #include "gdb_bfd.h"
 #include "gdbsupport/gdb_vecs.h"
 #include "registry.h"
+#include "solist.h"
 #include "gdbsupport/next-iterator.h"
 #include "gdbsupport/safe-iterator.h"
 #include <list>
@@ -59,8 +60,8 @@ public:
   typedef typename objfile_list::iterator::iterator_category iterator_category;
   typedef typename objfile_list::iterator::difference_type difference_type;
 
-  unwrapping_objfile_iterator (const objfile_list::iterator &iter)
-    : m_iter (iter)
+  unwrapping_objfile_iterator (objfile_list::iterator iter)
+    : m_iter (std::move (iter))
   {
   }
 
@@ -89,29 +90,7 @@ private:
 
 /* A range that returns unwrapping_objfile_iterators.  */
 
-struct unwrapping_objfile_range
-{
-  typedef unwrapping_objfile_iterator iterator;
-
-  unwrapping_objfile_range (objfile_list &ol)
-    : m_list (ol)
-  {
-  }
-
-  iterator begin () const
-  {
-    return iterator (m_list.begin ());
-  }
-
-  iterator end () const
-  {
-    return iterator (m_list.end ());
-  }
-
-private:
-
-  objfile_list &m_list;
-};
+using unwrapping_objfile_range = iterator_range<unwrapping_objfile_iterator>;
 
 /* A program space represents a symbolic view of an address space.
    Roughly speaking, it holds all the data associated with a
@@ -222,7 +201,7 @@ struct program_space
      a program space.  */
   ~program_space ();
 
-  typedef unwrapping_objfile_range objfiles_range;
+  using objfiles_range = unwrapping_objfile_range;
 
   /* Return an iterable object that can be used to iterate over all
      objfiles.  The basic use is in a foreach, like:
@@ -230,10 +209,12 @@ struct program_space
      for (objfile *objf : pspace->objfiles ()) { ... }  */
   objfiles_range objfiles ()
   {
-    return unwrapping_objfile_range (objfiles_list);
+    return objfiles_range
+      (unwrapping_objfile_iterator (objfiles_list.begin ()),
+       unwrapping_objfile_iterator (objfiles_list.end ()));
   }
 
-  typedef basic_safe_range<objfiles_range> objfiles_safe_range;
+  using objfiles_safe_range = basic_safe_range<objfiles_range>;
 
   /* An iterable object that can be used to iterate over all objfiles.
      The basic use is in a foreach, like:
@@ -244,7 +225,10 @@ struct program_space
      deleted during iteration.  */
   objfiles_safe_range objfiles_safe ()
   {
-    return objfiles_safe_range (objfiles_list);
+    return objfiles_safe_range
+      (objfiles_range
+	 (unwrapping_objfile_iterator (objfiles_list.begin ()),
+	  unwrapping_objfile_iterator (objfiles_list.end ())));
   }
 
   /* Add OBJFILE to the list of objfiles, putting it just before
@@ -270,7 +254,8 @@ struct program_space
      program space.  Use it like:
 
      for (so_list *so : pspace->solibs ()) { ... }  */
-  next_adapter<struct so_list> solibs () const;
+  so_list_range solibs () const
+  { return so_list_range (this->so_list); }
 
   /* Close and clear exec_bfd.  If we end up with no target sections
      to read memory from, this unpushes the exec_ops target.  */