fixed glib warnings about using g_mem_set_vtable() and revised memory limiting

 * we were basing the glib allocators on throwing std::bad_alloc just like
   the C++ operators. However, this always was unsafe since we were throwing
   exceptions across plain-C frames (Glib).
   Also, the memory vtable has been deprecated in Glib, resulting in
   ugly warnings.
 * Instead, we now let the C++ new/delete operators work like Glib
   by basing them on g_malloc/g_slice.
   This means they will assert and the application will terminate
   abnormally in case of OOM. OOMs cannot be handled properly anyway, so it is
   more important to have a good memory limiting mechanism.
 * Memory limiting has been completely revised.
   Instead of approximating undo stack sizes using virtual methods
   (which is unprecise and comes with a performance penalty),
   we now use a common base class SciTECO::Object to count the memory
   required by all objects allocated within SciTECO.
   This is less precise than using global replacement new/deletes
   which would allow us to control allocations in all C++ code including
   Scintilla, but they are only supported as of C++14 (GCC 5) and adding compile-time
   checks would be cumbersome.
   In any case, we're missing Glib allocations (esp. strings).
 * As a platform-specific extension, on Linux/glibc we use mallinfo()
   to count the exact memory usage of the process.
   On Windows, we use GetProcessMemoryInfo() -- the latter implementation
   is currently UNTESTED.
 * We use g_malloc() for new/delete operators when there is
   malloc_trim() since g_slice does not free heap chunks properly
   (probably does its own mmap()ing), rendering malloc_trim() ineffective.
   We've also benchmarked g_slice on Linux/glib (malloc_trim() shouldn't
   be available elsewhere) and found that it brings no significant
   performance benefit.
   On all other platforms, we use g_slice since it is assumed
   that it at least does not hurt.
   The new g_slice based allocators should be tested on MSVCRT
   since I assume that they bring a significant performance benefit
   on Windows.
 * Memory limiting does now work in batch mode as well and is still
   enabled by default.
 * The old UndoTokenWithSize CRTP hack could be removed.
   UndoStack operations should be a bit faster now.
   But on the other hand, there will be an overhead due to repeated
   memory limit checking on every processed character.

1 files changed, 0 insertions, 45 deletions

diff --git a/src/undo.cpp b/src/undo.cpp
index e189e23..4593fdc 100644
--- a/src/undo.cpp
+++ b/src/undo.cpp
@@ -29,12 +29,8 @@
 
 #include "sciteco.h"
 #include "cmdline.h"
-#include "interface.h"
-#include "error.h"
 #include "undo.h"
 
-#define SIZE_TO_MB(SIZE) ((gdouble)(SIZE))/(1024*1024)
-
 namespace SciTECO {
 
 //#define DEBUG
@@ -42,29 +38,6 @@ namespace SciTECO {
 UndoStack undo;
 
 void
-UndoStack::set_memory_limit(gsize new_limit)
-{
-	if (new_limit) {
-		if (!memory_limit) {
-			/* memory_usage outdated - recalculate */
-			UndoToken *token;
-
-			memory_usage = 0;
-			SLIST_FOREACH(token, &head, tokens)
-				memory_usage += token->get_size();
-		}
-
-		if (memory_usage > new_limit)
-			throw Error("Cannot set undo memory limit (%gmb): "
-			            "Current stack too large (%gmb).",
-			            SIZE_TO_MB(new_limit),
-			            SIZE_TO_MB(memory_usage));
-	}
-
-	push_var(memory_limit) = new_limit;
-}
-
-void
 UndoStack::push(UndoToken *token)
 {
 	/*
@@ -74,19 +47,6 @@ UndoStack::push(UndoToken *token)
 	 */
 	g_assert(enabled == true);
 
-	if (memory_limit) {
-		gsize token_size = token->get_size();
-
-		if (memory_usage + token_size > memory_limit) {
-			delete token;
-			throw Error("Undo stack memory limit (%gmb) exceeded. "
-			            "See <EJ> command.",
-			            SIZE_TO_MB(memory_limit));
-		}
-
-		memory_usage += token_size;
-	}
-
 #ifdef DEBUG
 	g_printf("UNDO PUSH %p\n", token);
 #endif
@@ -103,9 +63,6 @@ UndoStack::pop(gint pc)
 		g_printf("UNDO POP %p\n", top);
 		fflush(stdout);
 #endif
-
-		if (memory_limit)
-			memory_usage -= top->get_size();
 		top->run();
 
 		SLIST_REMOVE_HEAD(&head, tokens);
@@ -122,8 +79,6 @@ UndoStack::clear(void)
 		SLIST_REMOVE_HEAD(&head, tokens);
 		delete cur;
 	}
-
-	memory_usage = 0;
 }
 
 UndoStack::~UndoStack()