Re-add original SD FAT info access methods

Fixes esp8266#6081

The SD rewrite blanked out some of the internal FAT info.. Restore the
function calls and return proper values.

Author: earlephilhower

cores/esp8266/FS.h

@@ -24,6 +24,8 @@
 #include <memory>
 #include <Arduino.h>
 
+class SDClass;
+
 namespace fs {
 
 class File;
@@ -208,8 +210,10 @@ class FS
 
     bool gc();
 
+    friend class ::SDClass; // More of a frenemy, but SD needs internal implementation to get private FAT bits
 protected:
     FSImplPtr _impl;
+    FSImplPtr getImpl() { return _impl; }
 };
 
 } // namespace fs

libraries/SD/src/SD.h

@@ -84,35 +84,39 @@ class SDClass {
     }
 
     uint8_t type() {
-        return 0;//card.type();
+        sdfs::SDFSImpl* sd = static_cast<sdfs::SDFSImpl*>(SDFS.getImpl().get());
+        return sd->type();
     }
 
     uint8_t fatType() {
-        return 0;//volume.fatType();
+        sdfs::SDFSImpl* sd = static_cast<sdfs::SDFSImpl*>(SDFS.getImpl().get());
+        return sd->fatType();
     }
 
     size_t blocksPerCluster() {
-        return 0;//volume.blocksPerCluster();
+        sdfs::SDFSImpl* sd = static_cast<sdfs::SDFSImpl*>(SDFS.getImpl().get());
+        return sd->blocksPerCluster();
     }
 
     size_t totalClusters() {
-        return 0;//volume.clusterCount();
+        sdfs::SDFSImpl* sd = static_cast<sdfs::SDFSImpl*>(SDFS.getImpl().get());
+        return sd->totalClusters();
     }
 
     size_t blockSize() {
         return 512;
     }
 
     size_t totalBlocks() {
-        return 0;//(totalClusters() / blocksPerCluster());
+        return (totalClusters() / blocksPerCluster());
     }
 
     size_t clusterSize() {
-        return 0;//blocksPerCluster() * blockSize();
+        return blocksPerCluster() * blockSize();
     }
 
     size_t size() {
-        return 0;//(clusterSize() * totalClusters());
+        return (clusterSize() * totalClusters());
     }
 
 private:

libraries/SDFS/src/SDFS.h

@@ -159,6 +159,30 @@ class SDFSImpl : public FSImpl
 
     bool format() override;
 
+    // The following are not common FS interfaces, but are needed only to
+    // support the older SD.h exports
+    uint8_t type() {
+        return _fs.card()->type();
+    }
+    uint8_t fatType() {
+        return _fs.vol()->fatType();
+    }
+    size_t blocksPerCluster() {
+        return _fs.vol()->blocksPerCluster();
+    }
+    size_t totalClusters() {
+        return _fs.vol()->clusterCount();
+    }
+    size_t totalBlocks() {
+        return (totalClusters() / blocksPerCluster());
+    }
+    size_t clusterSize() {
+        return blocksPerCluster() * 512; // 512b block size
+    }
+    size_t size() {
+        return (clusterSize() * totalClusters());
+    }
+
 protected:
     friend class SDFileImpl;
     friend class SDFSDirImpl;