LittleFS: add overrides for Stream::send

cores/esp8266/FS.h

@@ -118,6 +118,18 @@ class File : public Stream
  time_t getCreationTime();
  void setTimeCallback(time_t (*cb)(void));
 
+ // Stream::send configuration
+
+ bool inputCanTimeout () override {
+ // unavailable data can't become later available
+ return false;
+ }
+
+ bool outputCanTimeout () override {
+ // free space for write can't increase later
+ return false;
+ }
+
 protected:
  FileImplPtr _p;
  time_t (*_timeCallback)(void) = nullptr;

libraries/LittleFS/examples/SpeedTest/SpeedTest.ino

@@ -132,13 +132,24 @@ void DoTest(FS *fs) {
  f.close();
  stop = millis();
  Serial.printf("==> Time to read 64KB in 1b chunks = %lu milliseconds = %s\n", stop - start, rate(start, stop, 65536));
+
+
+ start = millis();
+ auto dest = fs->open("/test1bw.bin", "w");
+ f = fs->open("/test1b.bin", "r");
+ auto copysize = f.sendAll(dest);
+ dest.close();
+ stop = millis();
+ Serial.printf("==> Time to copy %d = %zd bytes = %lu milliseconds = %s\n", f.size(), copysize, stop - start, rate(start, stop, f.size()));
+ f.close();
 }
 
 void setup() {
  Serial.begin(115200);
  Serial.printf("Beginning test\n");
  Serial.flush();
  DoTest(&TESTFS);
+ Serial.println("done");
 }
 
 void loop() {

libraries/LittleFS/src/LittleFS.h

@@ -241,7 +241,7 @@ class LittleFSImpl : public FSImpl
  DEBUGV("lfs_format, lfs_setattr 't': rc=%d\n", rc);
  return false;
  }
- 
+
  lfs_unmount(&_lfs);
  _mounted = false;
  }
@@ -372,6 +372,30 @@ class LittleFSFileImpl : public FileImpl
  }
  }
 
+ int availableForWrite () override {
+ if (!_opened || !_fd) {
+ return 0;
+ }
+
+ const auto f = _getFD();
+ const auto fs = _fs->getFS();
+
+ // check for remaining size in current block
+ // ignore inline feature (per code in lfs_file_rawwrite())
+ auto afw = fs->cfg->block_size - f->off;
+
+ if (afw == 0) {
+ // current block is full
+ // check for filesystem full (per code in lfs_alloc())
+ if (!(fs->free.i == fs->free.size && fs->free.ack == 0)) {
+ // fs is not full, return a full sector as free space
+ afw = fs->cfg->block_size;
+ }
+ }
+
+ return afw;
+ }
+
  size_t write(const uint8_t *buf, size_t size) override {
  if (!_opened || !_fd || !buf) {
  return 0;