Make static counters atomic

This ensures thread-safety

(requires: gcc >= 4.6, MSVC >= 2015)

src/Paragraph.cpp

@@ -61,6 +61,7 @@
 #include "support/lstrings.h"
 #include "support/textutils.h"
 
+#include <atomic>
 #include <sstream>
 #include <vector>
 
@@ -283,10 +284,11 @@ private:
 
 class Paragraph::Private
 {
-	// Enforce our own "copy" constructor by declaring the standard one and
-	// the assignment operator private without implementing them.
-	Private(Private const &);
-	Private & operator=(Private const &);
+	// Enforce our own "copy" constructor
+	Private(Private const &) = delete;
+	Private & operator=(Private const &) = delete;
+	// Unique ID generator
+	static int make_id();
 public:
 	///
 	Private(Paragraph * owner, Layout const & layout);
@@ -506,35 +508,37 @@ Paragraph::Private::Private(Paragraph * owner, Layout const & layout)
 }
 
 
-// Initialization of the counter for the paragraph id's,
-//
-// FIXME: There should be a more intelligent way to generate and use the
-// paragraph ids per buffer instead a global static counter for all InsetText
-// in the running program.
-// However, this per-session id is used in LFUN_PARAGRAPH_GOTO to
-// switch to a different buffer, as used in the outliner for instance.
-static int paragraph_id = -1;
+//static
+int Paragraph::Private::make_id()
+{
+	// The id is unique per session across buffers because it is used in
+	// LFUN_PARAGRAPH_GOTO to switch to a different buffer, for instance in the
+	// outliner.
+	// (thread-safe)
+	static atomic_uint next_id(0);
+	return next_id++;
+}
+
 
 Paragraph::Private::Private(Private const & p, Paragraph * owner)
 	: owner_(owner), inset_owner_(p.inset_owner_), fontlist_(p.fontlist_),
+	  id_(make_id()),
 	  params_(p.params_), changes_(p.changes_), insetlist_(p.insetlist_),
 	  begin_of_body_(p.begin_of_body_), text_(p.text_), words_(p.words_),
 	  layout_(p.layout_)
 {
-	id_ = ++paragraph_id;
 	requestSpellCheck(p.text_.size());
 }
 
 
 Paragraph::Private::Private(Private const & p, Paragraph * owner,
 	pos_type beg, pos_type end)
-	: owner_(owner), inset_owner_(p.inset_owner_),
+	: owner_(owner), inset_owner_(p.inset_owner_), id_(make_id()),
 	  params_(p.params_), changes_(p.changes_),
 	  insetlist_(p.insetlist_, beg, end),
 	  begin_of_body_(p.begin_of_body_), words_(p.words_),
 	  layout_(p.layout_)
 {
-	id_ = ++paragraph_id;
 	if (beg >= pos_type(p.text_.size()))
 		return;
 	text_ = p.text_.substr(beg, end - beg);

src/graphics/PreviewLoader.cpp

@@ -41,6 +41,7 @@
 #include "support/bind.h"
 #include "support/TempFile.h"
 
+#include <atomic>
 #include <fstream>
 #include <iomanip>
 #include <memory>
@@ -728,8 +729,7 @@ void PreviewLoader::Impl::startLoading(bool wait)
 	if (wait) {
 		ForkedCall call(buffer_.filePath(), buffer_.layoutPos());
 		int ret = call.startScript(ForkedProcess::Wait, command);
-		// FIXME THREAD
-		static int fake = (2^20) + 1;
+		static atomic_int fake((2^20) + 1);
 		int pid = fake++;
 		inprogress.pid = pid;
 		inprogress.command = command;

src/sgml.cpp

@@ -27,6 +27,7 @@
 #include "support/lstrings.h"
 #include "support/textutils.h"
 
+#include <atomic>
 #include <map>
 #include <QThreadStorage>
 
@@ -105,10 +106,8 @@ docstring sgml::escapeString(docstring const & raw)
 
 docstring const sgml::uniqueID(docstring const & label)
 {
-	// FIXME THREAD
-	// It seems unlikely there could be a problem here,
-	// but we could have concurrent access, in principle.
-	static unsigned int seed = 1000;
+	// thread-safe
+	static atomic_uint seed(1000);
 	return label + convert<docstring>(++seed);
 }