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, 6 insertions, 4 deletions

diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h
index e40504f..fe68730 100644
--- a/gdb/breakpoint.h
+++ b/gdb/breakpoint.h
@@ -30,6 +30,8 @@
 #include "gdbsupport/array-view.h"
 #include "gdbsupport/filtered-iterator.h"
 #include "gdbsupport/function-view.h"
+#include "gdbsupport/next-iterator.h"
+#include "gdbsupport/iterator-range.h"
 #include "gdbsupport/refcounted-object.h"
 #include "gdbsupport/safe-iterator.h"
 #include "cli/cli-script.h"
@@ -706,7 +708,7 @@ extern bool target_exact_watchpoints;
 
 /* bp_location linked list range.  */
 
-using bp_locations_range = next_adapter<bp_location>;
+using bp_location_range = next_range<bp_location>;
 
 /* Note that the ->silent field is not currently used by any commands
    (though the code is in there if it was to be, and set_raw_breakpoint
@@ -721,7 +723,7 @@ struct breakpoint
   virtual ~breakpoint ();
 
   /* Return a range of this breakpoint's locations.  */
-  bp_locations_range locations ();
+  bp_location_range locations ();
 
   /* Methods associated with this breakpoint.  */
   const breakpoint_ops *ops = NULL;
@@ -1715,7 +1717,7 @@ using breakpoint_iterator = next_iterator<breakpoint>;
 
 /* Breakpoint linked list range.  */
 
-using breakpoint_range = next_adapter<breakpoint, breakpoint_iterator>;
+using breakpoint_range = iterator_range<breakpoint_iterator>;
 
 /* Return a range to iterate over all breakpoints.  */
 
@@ -1746,7 +1748,7 @@ using tracepoint_iterator
 
 /* Breakpoint linked list range, filtering to only keep tracepoints.  */
 
-using tracepoint_range = next_adapter<breakpoint, tracepoint_iterator>;
+using tracepoint_range = iterator_range<tracepoint_iterator>;
 
 /* Return a range to iterate over all tracepoints.  */