SD Filesystem compatible with 8266 File, using latest SdFat (#5525)

* Add a FAT filesystem for SD cards to Arduino FS

Arduino forked a copy of SD lib several years ago, put their own wrapper
around it, and it's been languishing in our ESP8266 libraries ever since
as SD. It doesn't support long file names, has class names which
conflict with the ESP8266 internal names, and hasn't been updated in
ages.

The original author of the SD library has continued work in the
meantime, and produced a very feature rich implementation of SdFat. It
unfortunately also conflicts with the class names we use in ESP8266
Arduino and has a different API than the internal SPIFFS or proposed
LittleFS filesystem objects.

This PR puts a wrapper around the latest and greatest SdFat library,
by forking it and wrapping its classes in a private namespace "sdfat,"
and making as thin a wrapper as possible around it to conform to
the ESP8266 FS, File, and Dir classes.

This PR also removes the Arduino SD.h class library and rewrites it
using the new SDFS filesystem to make everything in the ESP8266
Arduino core compatible with each other.

By doing so it lets us use a single interface for anything needing a
file instead of multiple ones (see SDWebServer and how a different
object is needed vs. one serving from SPIFFS even though the logic is
all the same). Same for BearSSL's CertStores and probably a few others
I've missed, cleaning up our code base significantly.

Like LittleFS, silently create directories when a file is created with
a subdirectory specifier ("/path/to/file.txt") if they do not yet exist.

Adds a blacklist of sketches to skip in the CI process (because SdFat
has many examples which do not build properly on the ESP8266).

Now that LittleFS and SDFS have directory support, the FS needs to be
able to communicate whether a name is one or the other.  Add a simple
bool FS::isDirectory() and bool FS::isFile() method.  SPIFFS doesn't
have directories, so if it's valid it's a file and reported as such.

Add ::mkdir/::rmdir to the FS class to allow users to make and destroy
subdirectories.  SPIFFS directory operations will, of course, fail
and return false.

Emulate a 16MB SD card and allow test runner to exercise it by using
a custom SdFat HOST_MOCK-enabled object.

Throw out the original Arduino SD.h class and rewrite from scratch using
only the ESP8266 native SDFS calls.  This makes "SD" based applications
compatible with normal ESP8266 "File" and "FS" and "SPIFFS" operations.

The only major visible change for users is that long filenames now are
fully supported and work without any code changes.  If there are static
arrays of 11 bytes for old 8.3 names in code, they will need to be
adjusted.

While it is recommended to use the more powerful SDFS class to access SD
cards, this SD.h wrapper allows for use of existing Arduino libraries
which are built to only with with that SD class.

Additional helper functions added to ESP8266 native Filesystem:: classes
to help support this portability.

The rewrite is good enough to run the original SDWebServer and SD
example code without any changes.

* Add a FSConfig and SDFSConfig param to FS.begin()

Allows for configuration values to be passed into a filesystem via the
begin method.  By default, a FS will receive a nullptr and should so
whatever is appropriate.

The base FSConfig class has one parameter, _autoFormat, set by the
default constructor to true.

For SPIFFS, you can now disable auto formatting on mount failure by
passing in a FSConfig(false) object.

For SDFS a SDFSConfig parameter can be passed into config specifying the
chip select and SPI configuration.  If nothing is passed in, the begin
will fail since there are no safe default values here.

* Add FS::setConfig to set FS-specific options

Add a new call, FS::setConfig(const {SDFS,SPIFFS}Config *cfg), which
takes a FS-specific configuration object and copies any special settings
on a per-FS basis.  The call is only valid on unmounted filesystems, and
checks the type of object passed in matches the FS being configured.

Updates the docs and tests to utilize this new configuration method.

* Add ::truncate to File interface

Fixes #3846

* Use polledTimeout for formatting yields, cleanup

Use the new polledTimeout class to ensure a yield every 5ms while
formatting.

Add in default case handling and some debug messages when invalid inputs
specified.

* Make setConfig take const& ref, cleaner code

setConfig now can take a parameter defined directly in the call by using
a const &ref to it, leading to one less line of code to write and
cleaner reading of the code.

Also clean up SDFS implementation pointer definition.

libraries/SDFS/src/SDFS.h

@@ -0,0 +1,419 @@
+#ifndef SDFS_H
+#define SDFS_H
+
+/*
+ SDFS.h - file system wrapper for SdLib
+ Copyright (c) 2019 Earle F. Philhower, III.  All rights reserved.
+
+ Based on spiffs_api.h, which is:
+ | Copyright (c) 2015 Ivan Grokhotkov. All rights reserved.
+
+ This code was influenced by NodeMCU and Sming libraries, and first version of
+ Arduino wrapper written by Hristo Gochkov.
+
+ This file is part of the esp8266 core for Arduino environment.
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include <limits>
+#include <assert.h>
+#include "FS.h"
+#include "FSImpl.h"
+#include "debug.h"
+#include <SPI.h>
+#include <SdFat.h>
+#include <FS.h>
+
+using namespace fs;
+
+namespace sdfs {
+
+class SDFSFileImpl;
+class SDFSDirImpl;
+class SDFSConfig : public FSConfig
+{
+public:
+    SDFSConfig() {
+        _type = SDFSConfig::fsid::FSId;
+        _autoFormat = false;
+        _csPin = 4;
+        _spiSettings = SD_SCK_MHZ(10);
+	_part = 0;
+    }
+    SDFSConfig(uint8_t csPin, SPISettings spi) {
+        _type = SDFSConfig::fsid::FSId;
+        _autoFormat = false;
+        _csPin = csPin;
+        _spiSettings = spi;
+	_part = 0;
+    }
+
+    enum fsid { FSId = 0x53444653 };
+
+    SDFSConfig setAutoFormat(bool val = true) {
+        _autoFormat = val;
+        return *this;
+    }
+    SDFSConfig setCSPin(uint8_t pin) {
+        _csPin = pin;
+        return *this;
+    }
+    SDFSConfig setSPI(SPISettings spi) {
+        _spiSettings = spi;
+        return *this;
+    }
+    SDFSConfig setPart(uint8_t part) {
+        _part = part;
+        return *this;
+    }
+
+    // Inherit _type and _autoFormat
+    uint8_t     _csPin;
+    uint8_t     _part;
+    SPISettings _spiSettings;
+};
+
+class SDFSImpl : public FSImpl
+{
+public:
+    SDFSImpl() : _mounted(false)
+    {
+    }
+
+    FileImplPtr open(const char* path, OpenMode openMode, AccessMode accessMode) override;
+
+    bool exists(const char* path) {
+        return _mounted ? _fs.exists(path) : false;
+    }
+
+    DirImplPtr openDir(const char* path) override;
+
+    bool rename(const char* pathFrom, const char* pathTo) override {
+        return _mounted ? _fs.rename(pathFrom, pathTo) : false;
+    }
+
+    bool info(FSInfo& info) override {
+        if (!_mounted) {
+            DEBUGV("SDFS::info: FS not mounted\n");
+            return false;
+        }
+        info.maxOpenFiles = 999; // TODO - not valid
+        info.blockSize = _fs.vol()->blocksPerCluster() * 512;
+        info.pageSize = 0; // TODO ?
+        info.maxPathLength = 255; // TODO ?
+        info.totalBytes =_fs.vol()->volumeBlockCount() * 512;
+        info.usedBytes = info.totalBytes - (_fs.vol()->freeClusterCount() * _fs.vol()->blocksPerCluster() * 512);
+        return true;
+    }
+
+    bool remove(const char* path) override {
+        return _mounted ? _fs.remove(path) : false;
+    }
+
+    bool mkdir(const char* path) override {
+        return _mounted ? _fs.mkdir(path) : false;
+    }
+
+    bool rmdir(const char* path) override {
+        return _mounted ?_fs.rmdir(path) : false;
+    }
+
+    bool setConfig(const FSConfig &cfg) override
+    {
+        if ((cfg._type != SDFSConfig::fsid::FSId) || _mounted) {
+            DEBUGV("SDFS::setConfig: invalid config or already mounted\n");
+            return false;
+        }
+	_cfg = *static_cast<const SDFSConfig *>(&cfg);
+        return true;
+    }
+
+    bool begin() override {
+        if (_mounted) {
+            end();
+        }
+        _mounted = _fs.begin(_cfg._csPin, _cfg._spiSettings);
+        if (!_mounted && _cfg._autoFormat) {
+            format();
+            _mounted = _fs.begin(_cfg._csPin, _cfg._spiSettings);
+        }
+        return _mounted;
+    }
+
+    void end() override {
+        _mounted = false;
+        // TODO
+    }
+
+    bool format() override;
+
+protected:
+    friend class SDFileImpl;
+    friend class SDFSDirImpl;
+
+    sdfat::SdFat* getFs()
+    {
+        return &_fs;
+    }
+
+    static uint8_t _getFlags(OpenMode openMode, AccessMode accessMode) {
+        uint8_t mode = 0;
+        if (openMode & OM_CREATE) {
+            mode |= sdfat::O_CREAT;
+        }
+        if (openMode & OM_APPEND) {
+            mode |= sdfat::O_AT_END;
+        }
+        if (openMode & OM_TRUNCATE) {
+            mode |= sdfat::O_TRUNC;
+        }
+        if (accessMode & AM_READ) {
+            mode |= sdfat::O_READ;
+        }
+        if (accessMode & AM_WRITE) {
+            mode |= sdfat::O_WRITE;
+        }
+        return mode;
+    }
+
+    sdfat::SdFat _fs;
+    SDFSConfig   _cfg;
+    bool         _mounted;
+};
+
+
+class SDFSFileImpl : public FileImpl
+{
+public:
+    SDFSFileImpl(SDFSImpl *fs, std::shared_ptr<sdfat::File> fd, const char *name)
+        : _fs(fs), _fd(fd), _opened(true)
+    {
+        _name = std::shared_ptr<char>(new char[strlen(name) + 1], std::default_delete<char[]>());
+        strcpy(_name.get(), name);
+    }
+
+    ~SDFSFileImpl() override
+    {
+        flush();
+        close();
+    }
+
+    size_t write(const uint8_t *buf, size_t size) override
+    {
+        return _opened ? _fd->write(buf, size) : -1;
+    }
+
+    size_t read(uint8_t* buf, size_t size) override
+    {
+        return _opened ? _fd->read(buf, size) : -1;
+    }
+
+    void flush() override
+    {
+        if (_opened) {
+            _fd->flush();
+            _fd->sync();
+        }
+    }
+
+    bool seek(uint32_t pos, SeekMode mode) override
+    {
+        if (!_opened) {
+            return false;
+        }
+        switch (mode) {
+            case SeekSet:
+                return _fd->seekSet(pos);
+            case SeekEnd:
+                return _fd->seekEnd(-pos); // TODO again, odd from POSIX
+            case SeekCur:
+                return _fd->seekCur(pos);
+            default:
+                // Should not be hit, we've got an invalid seek mode
+                DEBUGV("SDFSFileImpl::seek: invalid seek mode %d\n", mode);
+		assert((mode==SeekSet) || (mode==SeekEnd) || (mode==SeekCur)); // Will fail and give meaningful assert message
+		return false;
+        }
+    }
+
+    size_t position() const override
+    {
+        return _opened ? _fd->curPosition() : 0;
+    }
+
+    size_t size() const override
+    {
+        return _opened ? _fd->fileSize() : 0;
+    }
+
+    bool truncate(uint32_t size) override
+    {
+        if (!_opened) {
+            DEBUGV("SDFSFileImpl::truncate: file not opened\n");
+            return false;
+        }
+        return _fd->truncate(size);
+    }
+
+    void close() override
+    {
+        if (_opened) {
+            _fd->close();
+            _opened = false;
+        }
+    }
+
+    const char* name() const override
+    {
+        if (!_opened) {
+            DEBUGV("SDFSFileImpl::name: file not opened\n");
+            return nullptr;
+        } else {
+            const char *p = _name.get();
+            const char *slash = strrchr(p, '/');
+            // For names w/o any path elements, return directly
+            // If there are slashes, return name after the last slash
+            // (note that strrchr will return the address of the slash,
+            // so need to increment to ckip it)
+            return (slash && slash[1]) ? slash + 1 : p;
+        }
+    }
+
+    const char* fullName() const override
+    {
+        return _opened ? _name.get() : nullptr;
+    }
+
+    bool isFile() const override
+    {
+        return _opened ? _fd->isFile() : false;;
+    }
+
+    bool isDirectory() const override
+    {
+        return _opened ? _fd->isDirectory() : false;
+    }
+
+
+protected:
+    SDFSImpl*                     _fs;
+    std::shared_ptr<sdfat::File>  _fd;
+    std::shared_ptr<char>         _name;
+    bool                          _opened;
+};
+
+class SDFSDirImpl : public DirImpl
+{
+public:
+    SDFSDirImpl(const String& pattern, SDFSImpl* fs, std::shared_ptr<sdfat::File> dir, const char *dirPath = nullptr)
+        : _pattern(pattern), _fs(fs), _dir(dir), _valid(false), _dirPath(nullptr)
+    {
+        if (dirPath) {
+            _dirPath = std::shared_ptr<char>(new char[strlen(dirPath) + 1], std::default_delete<char[]>());
+            strcpy(_dirPath.get(), dirPath);
+        }
+    }
+
+    ~SDFSDirImpl() override
+    {
+        _dir->close();
+    }
+
+    FileImplPtr openFile(OpenMode openMode, AccessMode accessMode) override
+    {
+        if (!_valid) {
+            return FileImplPtr();
+        }
+        // MAX_PATH on FAT32 is potentially 260 bytes per most implementations
+        char tmpName[260];
+        snprintf(tmpName, sizeof(tmpName), "%s%s%s", _dirPath.get() ? _dirPath.get() : "", _dirPath.get()&&_dirPath.get()[0]?"/":"", _lfn);
+        return _fs->open((const char *)tmpName, openMode, accessMode);
+    }
+
+    const char* fileName() override
+    {
+        if (!_valid) {
+            DEBUGV("SDFSDirImpl::fileName: directory not valid\n");
+            return nullptr;
+        }
+        return (const char*) _lfn; //_dirent.name;
+    }
+
+    size_t fileSize() override
+    {
+        if (!_valid) {
+            return 0;
+        }
+
+        return _size;
+    }
+
+    bool isFile() const override
+    {
+        return _valid ? _isFile : false;
+    }
+
+    bool isDirectory() const override
+    {
+        return _valid ? _isDirectory : false;
+    }
+
+    bool next() override
+    {
+        const int n = _pattern.length();
+        do {
+            sdfat::File file;
+            file.openNext(_dir.get(), sdfat::O_READ);
+            if (file) {
+                _valid = 1;
+                _size = file.fileSize();
+                _isFile = file.isFile();
+                _isDirectory = file.isDirectory();
+                file.getName(_lfn, sizeof(_lfn));
+                file.close();
+            } else {
+                _valid = 0;
+            }
+        } while(_valid && strncmp((const char*) _lfn, _pattern.c_str(), n) != 0);
+        return _valid;
+    }
+
+    bool rewind() override
+    {
+        _valid = false;
+        _dir->rewind();
+        return true;
+    }
+
+protected:
+    String                       _pattern;
+    SDFSImpl*                    _fs;
+    std::shared_ptr<sdfat::File> _dir;
+    bool                         _valid;
+    char                         _lfn[64];
+    std::shared_ptr<char>        _dirPath;
+    uint32_t                     _size;
+    bool                         _isFile;
+    bool                         _isDirectory;
+};
+
+}; // namespace sdfs
+
+#if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_SDFS)
+extern FS SDFS;
+using sdfs::SDFSConfig;
+#endif
+
+#endif // SDFS.h