[ion] Ion::Storage is not a global variable anymore

apps/code/editor_controller.cpp

@@ -4,8 +4,7 @@
 #include "variable_box_controller.h"
 #include <apps/code/app.h>
 #include <escher/metric.h>
-
-extern Ion::Storage storage;
+#include <ion.h>
 
 namespace Code {
 
@@ -28,7 +27,7 @@ void EditorController::setScript(Script script) {
   m_script = script;
   const char * scriptBody = m_script.readContent();
   size_t scriptBodySize = strlen(scriptBody)+1;
-  size_t availableScriptSize = scriptBodySize + storage.availableSize();
+  size_t availableScriptSize = scriptBodySize + Ion::Storage::sharedStorage()->availableSize();
   assert(m_areaBuffer == nullptr);
   m_areaBuffer = new char[availableScriptSize];
   strlcpy(m_areaBuffer, scriptBody, scriptBodySize);

apps/code/script_store.cpp

@@ -26,7 +26,7 @@ void ScriptStore::deleteAllScripts() {
 }
 
 bool ScriptStore::isFull() {
-  return (numberOfScripts() >= k_maxNumberOfScripts || storage.availableSize() < k_fullFreeSpaceSizeLimit);
+  return (numberOfScripts() >= k_maxNumberOfScripts || Ion::Storage::sharedStorage()->availableSize() < k_fullFreeSpaceSizeLimit);
 }
 
 void ScriptStore::scanScriptsForFunctionsAndVariables(void * context, ScanCallback storeFunction, ScanCallback storeVariable) {
@@ -124,7 +124,7 @@ Script::ErrorStatus ScriptStore::addScriptFromTemplate(const ScriptTemplate * sc
   char * body = new char[scriptSize+Script::k_importationStatusSize];
   body[0] = 1;
   strlcpy(body+Script::k_importationStatusSize, scriptTemplate->content(), scriptSize);
-  Script::ErrorStatus err = storage.createRecord(scriptTemplate->name(), body, scriptSize+Script::k_importationStatusSize);
+  Script::ErrorStatus err = Ion::Storage::sharedStorage()->createRecord(scriptTemplate->name(), body, scriptSize+Script::k_importationStatusSize);
   assert(err != Script::ErrorStatus::NonCompliantName);
   delete[] body;
   return err;

apps/code/script_store.h

@@ -1,6 +1,7 @@
 #ifndef CODE_SCRIPT_STORE_H
 #define CODE_SCRIPT_STORE_H
 
+#include <ion.h>
 #include "script.h"
 #include "script_template.h"
 #include <python/port/port.h>
@@ -8,8 +9,6 @@ extern "C" {
 #include "py/parse.h"
 }
 
-extern Ion::Storage storage;
-
 namespace Code {
 
 class ScriptStore : public MicroPython::ScriptProvider {
@@ -20,13 +19,13 @@ public:
 
   ScriptStore();
   Script scriptAtIndex(int index) {
-    return Script(storage.recordWithExtensionAtIndex(k_scriptExtension, index));
+    return Script(Ion::Storage::sharedStorage()->recordWithExtensionAtIndex(k_scriptExtension, index));
   }
   Script scriptNamed(const char * name) {
-    return Script(storage.recordNamed(name));
+    return Script(Ion::Storage::sharedStorage()->recordNamed(name));
   }
   int numberOfScripts() {
-    return storage.numberOfRecordsWithExtension(k_scriptExtension);
+    return Ion::Storage::sharedStorage()->numberOfRecordsWithExtension(k_scriptExtension);
   }
   Ion::Storage::Record::ErrorStatus addNewScript() {
     return addScriptFromTemplate(ScriptTemplate::Empty());

ion/include/ion/storage.h

@@ -5,19 +5,12 @@
 
 namespace Ion {
 
-class Storage;
-
-}
-
-extern Ion::Storage storage;
-
-namespace Ion {
-
 /* Storage : | Magic |             Record1             |            Record2              | ... | Magic |
  *           | Magic | Size1(uint16_t) | Name1 | Body1 | Size2(uint16_t) | Name2 | Body2 | ... | Magic */
 
 class Storage {
 public:
+  static Storage * sharedStorage();
   class Record {
     /* A Record is identified by the CRC32 on his name because:
      * - a record is identified by its name which is unique
@@ -46,19 +39,19 @@ public:
       return m_nameCRC32 == 0;
     }
     const char * name() const {
-      return storage.nameOfRecord(*this);
+      return Storage::sharedStorage()->nameOfRecord(*this);
     }
     ErrorStatus setName(const char * name) {
-      return storage.setNameOfRecord(*this, name);
+      return Storage::sharedStorage()->setNameOfRecord(*this, name);
     }
     Data value() const {
-      return storage.valueOfRecord(*this);
+      return Storage::sharedStorage()->valueOfRecord(*this);
     }
     ErrorStatus setValue(Data data) {
-      return storage.setValueOfRecord(*this, data);
+      return Storage::sharedStorage()->setValueOfRecord(*this, data);
     }
     void destroy() {
-      return storage.destroyRecord(*this);
+      return Storage::sharedStorage()->destroyRecord(*this);
     }
   private:
     uint32_t m_nameCRC32;

ion/src/shared/platform_info.cpp

@@ -13,7 +13,10 @@
 #define HEADER_SECTION
 #endif
 
-extern Ion::Storage storage;
+namespace Ion {
+extern char staticStorageArea[];
+}
+constexpr void * storageAddress = &(Ion::staticStorageArea);
 
 class PlatformInfo {
 public:
@@ -21,7 +24,7 @@ public:
     m_header(Magic),
     m_version{EPSILON_VERSION},
     m_patchLevel{PATCH_LEVEL},
-    m_storageAddress(&storage),
+    m_storageAddress(storageAddress),
     m_footer(Magic) { }
   const char * version() const {
     assert(m_storageAddress != nullptr);

ion/src/shared/storage.cpp

@@ -1,11 +1,31 @@
 #include <ion.h>
 #include <string.h>
 #include <assert.h>
-
-Ion::Storage storage;
+#include <new>
 
 namespace Ion {
 
+/* We want to implement a simple singleton pattern, to make sure the storage is
+ * initialized on first use, therefore preventing the static init order fiasco.
+ * That being said, we rely on knowing where the storage resides in the device's
+ * memory at compile time. Indeed, we want to advertise the static storage's
+ * memory address in the PlatformInfo structure (so that we can read and write
+ * it in DFU).
+ * Using a "static Storage storage;" variable makes it a local symbol at best,
+ * preventing the PlatformInfo from retrieving its address. And making the
+ * Storage variable global yields the static init fiasco issue. We're working
+ * around both issues by creating a global staticStorageArea buffer, and by
+ * placement-newing the Storage into that area on first use. */
+
+char staticStorageArea[sizeof(Storage)] = {0};
+Storage * Storage::sharedStorage() {
+  static Storage * storage = nullptr;
+  if (storage == nullptr) {
+    storage = new (staticStorageArea) Storage();
+  }
+  return storage;
+}
+
 Storage::Record::Record(const char * name) {
   if (name == nullptr) {
     m_nameCRC32 = 0;