Refactor fetchTile for clarity and less branching (#76)

Author: CelliesProjects

src/OpenStreetMap-esp32.cpp

@@ -454,45 +454,42 @@ bool OpenStreetMap::fetchTile(CachedTile &tile, uint32_t x, uint32_t y, uint8_t
         return false;
     }
 
+    PNG *png = getPNGForCore();
+    if (!png)
+    {
+        result = "PNG decoder unavailable";
+        return false;
+    }
+
     char url[64];
     snprintf(url, sizeof(url), "https://tile.openstreetmap.org/%u/%u/%u.png",
              static_cast<unsigned int>(zoom),
              static_cast<unsigned int>(x),
              static_cast<unsigned int>(y));
 
-    int decodeResult;
-    {
-        auto buffer = urlToBuffer(url, result);
-        if (!buffer)
-            return false;
-
-        PNG *png = getPNGForCore();
-        if (!png)
-        {
-            result = "PNG decoder unavailable";
-            return false;
-        }
-
-        const int16_t rc = png->openRAM(buffer.value()->get(), buffer.value()->size(), PNGDraw);
-        if (rc != PNG_SUCCESS)
-        {
-            result = "PNG Decoder Error: " + String(rc);
-            return false;
-        }
+    const auto buffer = urlToBuffer(url, result);
+    if (!buffer)
+        return false;
 
-        if (png->getWidth() != OSM_TILESIZE || png->getHeight() != OSM_TILESIZE)
-        {
-            result = "Unexpected tile size: w=" + String(png->getWidth()) + " h=" + String(png->getHeight());
-            return false;
-        }
+    const int16_t rc = png->openRAM(buffer.value()->get(), buffer.value()->size(), PNGDraw);
+    if (rc != PNG_SUCCESS)
+    {
+        result = "PNG Decoder Error: " + String(rc);
+        return false;
+    }
 
-        currentInstance = this;
-        currentTileBuffer = tile.buffer;
-        decodeResult = png->decode(0, PNG_FAST_PALETTE);
-        currentTileBuffer = nullptr;
-        currentInstance = nullptr;
+    if (png->getWidth() != OSM_TILESIZE || png->getHeight() != OSM_TILESIZE)
+    {
+        result = "Unexpected tile size: w=" + String(png->getWidth()) + " h=" + String(png->getHeight());
+        return false;
     }
 
+    currentInstance = this;
+    currentTileBuffer = tile.buffer;
+    const int decodeResult = png->decode(0, PNG_FAST_PALETTE);
+    currentTileBuffer = nullptr;
+    currentInstance = nullptr;
+
     if (decodeResult != PNG_SUCCESS)
     {
         result = "Decoding " + String(url) + " failed with code: " + String(decodeResult);

src/OpenStreetMap-esp32.hpp

@@ -43,7 +43,7 @@ constexpr uint16_t OSM_TILE_TIMEOUT_MS = 2500;
 constexpr uint16_t OSM_DEFAULT_CACHE_ITEMS = 10;
 constexpr uint16_t OSM_MAX_ZOOM = 18;
 constexpr UBaseType_t OSM_TASK_PRIORITY = 10;
-constexpr uint32_t OSM_TASK_STACKSIZE = 4096;
+constexpr uint32_t OSM_TASK_STACKSIZE = 5120;
 constexpr uint32_t OSM_JOB_QUEUE_SIZE = 50;
 
 using tileList = std::vector<std::pair<uint32_t, int32_t>>;