SD Filesystem compatible with 8266 File, using latest SdFat by earlephilhower · Pull Request #5525 · esp8266/Arduino (original) (raw)

--edit-- Ready for trial, memory error cleaned up, SDWebServer demo and host tests running locally

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.