fix: ActivityManager tweaks (#1220)

## Summary

**What is the goal of this PR?**

Small tweaks to #1016:
- Only Activity and ActivityManager can access activityResultHandler and
activityResult
- `[[maybe_unused]]` in RenderLock constructor
- Only ActivityManager and RenderLock can access renderingMutex
- Missing renderUpdate after failed wifi selection
- Standardize on activities calling finish instead of
activityManager.popActivity
- Hold RenderLock while mutating state in EpubReaderActivity result
handlers

---

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src/activities/Activity.h

@@ -13,15 +13,17 @@
 #include "RenderLock.h"
 
 class Activity {
+  friend class ActivityManager;
+
  protected:
   std::string name;
   GfxRenderer& renderer;
   MappedInputManager& mappedInput;
 
- public:
   ActivityResultHandler resultHandler;
   ActivityResult result;
 
+ public:
   explicit Activity(std::string name, GfxRenderer& renderer, MappedInputManager& mappedInput)
       : name(std::move(name)), renderer(renderer), mappedInput(mappedInput) {}
   virtual ~Activity() = default;

src/activities/ActivityManager.cpp

@@ -232,7 +232,7 @@ RenderLock::RenderLock() {
   isLocked = true;
 }
 
-RenderLock::RenderLock(Activity& /* unused */) {
+RenderLock::RenderLock([[maybe_unused]] Activity&) {
   xSemaphoreTake(activityManager.renderingMutex, portMAX_DELAY);
   isLocked = true;
 }

src/activities/ActivityManager.h

@@ -11,7 +11,6 @@
 
 #include "GfxRenderer.h"
 #include "MappedInputManager.h"
-#include "RenderLock.h"
 
 class Activity;    // forward declaration
 class RenderLock;  // forward declaration
@@ -31,6 +30,8 @@ class RenderLock;  // forward declaration
  * - onActivityResult is implemented via a callback instead of a separate method, for simplicity
  */
 class ActivityManager {
+  friend class RenderLock;
+
  protected:
   GfxRenderer& renderer;
   MappedInputManager& mappedInput;
@@ -49,6 +50,10 @@ class ActivityManager {
   static void renderTaskTrampoline(void* param);
   [[noreturn]] virtual void renderTaskLoop();
 
+  // Mutex to protect rendering operations from race conditions
+  // Must only be used via RenderLock
+  SemaphoreHandle_t renderingMutex = nullptr;
+
   // Whether to trigger a render after the current loop()
   // This variable must only be set by the main loop, to avoid race conditions
   bool requestedUpdate = false;
@@ -61,10 +66,6 @@ class ActivityManager {
   }
   ~ActivityManager() { assert(false); /* should never be called */ };
 
-  // Mutex to protect rendering operations from race conditions
-  // Must only be used via RenderLock
-  SemaphoreHandle_t renderingMutex = nullptr;
-
   void begin();
   void loop();
 

src/activities/browser/OpdsBookBrowserActivity.cpp

@@ -383,5 +383,6 @@ void OpdsBookBrowserActivity::onWifiSelectionComplete(const bool connected) {
     WiFi.mode(WIFI_OFF);
     state = BrowserState::ERROR;
     errorMessage = tr(STR_WIFI_CONN_FAILED);
+    requestUpdate();
   }
 }

src/activities/network/CalibreConnectActivity.cpp

@@ -63,7 +63,7 @@ void CalibreConnectActivity::onExit() {
 
 void CalibreConnectActivity::onWifiSelectionComplete(const bool connected) {
   if (!connected) {
-    activityManager.popActivity();
+    finish();
     return;
   }
 
@@ -162,7 +162,7 @@ void CalibreConnectActivity::loop() {
   }
 
   if (exitRequested) {
-    activityManager.popActivity();
+    finish();
     return;
   }
 }

src/activities/reader/EpubReaderActivity.cpp

@@ -320,6 +320,7 @@ void EpubReaderActivity::onReaderMenuConfirm(EpubReaderMenuActivity::MenuAction
           std::make_unique<EpubReaderChapterSelectionActivity>(renderer, mappedInput, epub, path, spineIdx),
           [this](const ActivityResult& result) {
             if (!result.isCancelled && currentSpineIndex != std::get<ChapterResult>(result.data).spineIndex) {
+              RenderLock lock(*this);
               currentSpineIndex = std::get<ChapterResult>(result.data).spineIndex;
               nextPageNumber = 0;
               section.reset();
@@ -421,6 +422,7 @@ void EpubReaderActivity::onReaderMenuConfirm(EpubReaderMenuActivity::MenuAction
               if (!result.isCancelled) {
                 const auto& sync = std::get<SyncResult>(result.data);
                 if (currentSpineIndex != sync.spineIndex || (section && section->currentPage != sync.page)) {
+                  RenderLock lock(*this);
                   currentSpineIndex = sync.spineIndex;
                   nextPageNumber = sync.page;
                   section.reset();

src/activities/settings/CalibreSettingsActivity.cpp

@@ -27,7 +27,7 @@ void CalibreSettingsActivity::onExit() { Activity::onExit(); }
 
 void CalibreSettingsActivity::loop() {
   if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
-    activityManager.popActivity();
+    finish();
     return;
   }
 

src/activities/settings/KOReaderSettingsActivity.cpp

@@ -29,7 +29,7 @@ void KOReaderSettingsActivity::onExit() { Activity::onExit(); }
 
 void KOReaderSettingsActivity::loop() {
   if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
-    activityManager.popActivity();
+    finish();
     return;
   }
 

src/activities/settings/OtaUpdateActivity.cpp

@@ -13,7 +13,7 @@
 void OtaUpdateActivity::onWifiSelectionComplete(const bool success) {
   if (!success) {
     LOG_ERR("OTA", "WiFi connection failed, exiting");
-    activityManager.popActivity();
+    finish();
     return;
   }
 
@@ -172,7 +172,7 @@ void OtaUpdateActivity::loop() {
     }
 
     if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
-      activityManager.popActivity();
+      finish();
     }
 
     return;
@@ -180,14 +180,14 @@ void OtaUpdateActivity::loop() {
 
   if (state == FAILED) {
     if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
-      activityManager.popActivity();
+      finish();
     }
     return;
   }
 
   if (state == NO_UPDATE) {
     if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
-      activityManager.popActivity();
+      finish();
     }
     return;
   }