C++ spiffs_get_cache函数代码示例

// frees cached page
static s32_t ICACHE_FLASH_ATTR
spiffs_cache_page_free(spiffs *fs, int ix, u8_t write_back) {
  s32_t res = SPIFFS_OK;
  spiffs_cache *cache = spiffs_get_cache(fs);
  spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, ix);
  if (cache->cpage_use_map & (1<<ix)) {
    if (write_back &&
        (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) == 0 &&
        (cp->flags & SPIFFS_CACHE_FLAG_DIRTY)) {
      u8_t *mem =  spiffs_get_cache_page(fs, cache, ix);
      res = fs->cfg.hal_write_f(SPIFFS_PAGE_TO_PADDR(fs, cp->pix), SPIFFS_CFG_LOG_PAGE_SZ(fs), mem);
    }

    cp->flags = 0;
    cache->cpage_use_map &= ~(1 << ix);

    if (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) {
      SPIFFS_CACHE_DBG("CACHE_FREE: free cache page %d objid %04x\n", ix, cp->obj_id);
    } else {
      SPIFFS_CACHE_DBG("CACHE_FREE: free cache page %d pix %04x\n", ix, cp->pix);
    }
  }

  return res;
}

// removes the oldest accessed cached page
static s32_t ICACHE_FLASH_ATTR
spiffs_cache_page_remove_oldest(spiffs *fs, u8_t flag_mask, u8_t flags) {
  s32_t res = SPIFFS_OK;
  spiffs_cache *cache = spiffs_get_cache(fs);

  if ((cache->cpage_use_map & cache->cpage_use_mask) != cache->cpage_use_mask) {
    // at least one free cpage
    return SPIFFS_OK;
  }

  // all busy, scan thru all to find the cpage which has oldest access
  int i;
  int cand_ix = -1;
  u32_t oldest_val = 0;
  for (i = 0; i < cache->cpage_count; i++) {
    spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i);
    if ((cache->last_access - cp->last_access) > oldest_val &&
        (cp->flags & flag_mask) == flags) {
      oldest_val = cache->last_access - cp->last_access;
      cand_ix = i;
    }
  }

  if (cand_ix >= 0) {
    res = spiffs_cache_page_free(fs, cand_ix, 1);
  }

  return res;
}

// Checks if there are any cached writes for the object id associated with
// given filehandle. If so, these writes are flushed.
static s32_t spiffs_fflush_cache(spiffs *fs, spiffs_file fh) {
  s32_t res = SPIFFS_OK;
#if SPIFFS_CACHE_WR

  spiffs_fd *fd;
  res = spiffs_fd_get(fs, fh, &fd);
  SPIFFS_API_CHECK_RES(fs, res);

  if ((fd->flags & SPIFFS_DIRECT) == 0) {
    if (fd->cache_page == 0) {
      // see if object id is associated with cache already
      fd->cache_page = spiffs_cache_page_get_by_fd(fs, fd);
    }
    if (fd->cache_page) {
      SPIFFS_CACHE_DBG("CACHE_WR_DUMP: dumping cache page %d for fd %d:%04x, flush, offs:%d size:%d\n",
          fd->cache_page->ix, fd->file_nbr,  fd->obj_id, fd->cache_page->offset, fd->cache_page->size);
      res = spiffs_hydro_write(fs, fd,
          spiffs_get_cache_page(fs, spiffs_get_cache(fs), fd->cache_page->ix),
          fd->cache_page->offset, fd->cache_page->size);
      if (res < SPIFFS_OK) {
        fs->errno = res;
      }
      spiffs_cache_fd_release(fs, fd->cache_page);
    }
  }
#endif

  return res;
}

// initializes the cache
void ICACHE_FLASH_ATTR
spiffs_cache_init(spiffs *fs) {
  if (fs->cache == 0) return;
  u32_t sz = fs->cache_size;
  u32_t cache_mask = 0;
  int i;
  int cache_entries =
      (sz - sizeof(spiffs_cache)) / (SPIFFS_CACHE_PAGE_SIZE(fs));
  if (cache_entries <= 0) return;

  for (i = 0; i < cache_entries; i++) {
    cache_mask <<= 1;
    cache_mask |= 1;
  }

  spiffs_cache cache;
  memset(&cache, 0, sizeof(spiffs_cache));
  cache.cpage_count = cache_entries;
  cache.cpages = (u8_t *)((u8_t *)fs->cache + sizeof(spiffs_cache));

  cache.cpage_use_map = 0xffffffff;
  cache.cpage_use_mask = cache_mask;
  memcpy(fs->cache, &cache, sizeof(spiffs_cache));

  spiffs_cache *c = spiffs_get_cache(fs);

  memset(c->cpages, 0, c->cpage_count * SPIFFS_CACHE_PAGE_SIZE(fs));

  c->cpage_use_map &= ~(c->cpage_use_mask);
  for (i = 0; i < cache.cpage_count; i++) {
    spiffs_get_cache_page_hdr(fs, c, i)->ix = i;
  }
}

// reads from spi flash or the cache
s32_t spiffs_phys_rd(
    spiffs *fs,
    u8_t op,
    spiffs_file fh,
    u32_t addr,
    u32_t len,
    u8_t *dst) {
  (void)fh;
  s32_t res = SPIFFS_OK;
  spiffs_cache *cache = spiffs_get_cache(fs);
  spiffs_cache_page *cp =  spiffs_cache_page_get(fs, SPIFFS_PADDR_TO_PAGE(fs, addr));
  cache->last_access++;
  if (cp) {
    // we've already got one, you see
#if SPIFFS_CACHE_STATS
    fs->cache_hits++;
#endif
    cp->last_access = cache->last_access;
    u8_t *mem =  spiffs_get_cache_page(fs, cache, cp->ix);
    memcpy(dst, &mem[SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr)], len);
  } else {
    if ((op & SPIFFS_OP_TYPE_MASK) == SPIFFS_OP_T_OBJ_LU2) {
      // for second layer lookup functions, we do not cache in order to prevent shredding
      return SPIFFS_HAL_READ(fs, addr, len, dst);
    }
#if SPIFFS_CACHE_STATS
    fs->cache_misses++;
#endif
    // this operation will always free one cache page (unless all already free),
    // the result code stems from the write operation of the possibly freed cache page
    res = spiffs_cache_page_remove_oldest(fs, SPIFFS_CACHE_FLAG_TYPE_WR, 0);

    cp = spiffs_cache_page_allocate(fs);
    if (cp) {
      cp->flags = SPIFFS_CACHE_FLAG_WRTHRU;
      cp->pix = SPIFFS_PADDR_TO_PAGE(fs, addr);

      s32_t res2 = SPIFFS_HAL_READ(fs,
          addr - SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr),
          SPIFFS_CFG_LOG_PAGE_SZ(fs),
          spiffs_get_cache_page(fs, cache, cp->ix));
      if (res2 != SPIFFS_OK) {
        // honor read failure before possible write failure (bad idea?)
        res = res2;
      }
      u8_t *mem =  spiffs_get_cache_page(fs, cache, cp->ix);
      memcpy(dst, &mem[SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr)], len);
    } else {
      // this will never happen, last resort for sake of symmetry
      s32_t res2 = SPIFFS_HAL_READ(fs, addr, len, dst);
      if (res2 != SPIFFS_OK) {
        // honor read failure before possible write failure (bad idea?)
        res = res2;
      }
    }
  }
  return res;
}

// reads from spi flash or the cache
s32_t ICACHE_FLASH_ATTR
spiffs_phys_rd(
    spiffs *fs,
    u8_t op,
    spiffs_file fh,
    u32_t addr,
    u32_t len,
    u8_t *dst) {
  (void)fh;
  s32_t res = SPIFFS_OK;
  spiffs_cache *cache = spiffs_get_cache(fs);
  spiffs_cache_page *cp =  spiffs_cache_page_get(fs, SPIFFS_PADDR_TO_PAGE(fs, addr));
  cache->last_access++;
  if (cp) {
#if SPIFFS_CACHE_STATS
    fs->cache_hits++;
#endif
    cp->last_access = cache->last_access;
  } else {
    if ((op & SPIFFS_OP_TYPE_MASK) == SPIFFS_OP_T_OBJ_LU2) {
      // for second layer lookup functions, we do not cache in order to prevent shredding
      return fs->cfg.hal_read_f(
          addr ,
          len,
          dst);
    }
#if SPIFFS_CACHE_STATS
    fs->cache_misses++;
#endif
    res = spiffs_cache_page_remove_oldest(fs, SPIFFS_CACHE_FLAG_TYPE_WR, 0);
    cp = spiffs_cache_page_allocate(fs);
    if (cp) {
      cp->flags = SPIFFS_CACHE_FLAG_WRTHRU;
      cp->pix = SPIFFS_PADDR_TO_PAGE(fs, addr);
    }

    s32_t res2 = fs->cfg.hal_read_f(
        addr - SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr),
        SPIFFS_CFG_LOG_PAGE_SZ(fs),
        spiffs_get_cache_page(fs, cache, cp->ix));
    if (res2 != SPIFFS_OK) {
      res = res2;
    }
  }
  u8_t *mem =  spiffs_get_cache_page(fs, cache, cp->ix);
  memcpy(dst, &mem[SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr)], len);
  return res;
}

// returns cached page for give page index, or null if no such cached page
static spiffs_cache_page *ICACHE_FLASH_ATTR spiffs_cache_page_get(spiffs *fs, spiffs_page_ix pix) {
  spiffs_cache *cache = spiffs_get_cache(fs);
  if ((cache->cpage_use_map & cache->cpage_use_mask) == 0) return 0;
  int i;
  for (i = 0; i < cache->cpage_count; i++) {
    spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i);
    if ((cache->cpage_use_map & (1<<i)) &&
        (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) == 0 &&
        cp->pix == pix ) {
      SPIFFS_CACHE_DBG("CACHE_GET: have cache page %i for %04x\n", i, pix);
      cp->last_access = cache->last_access;
      return cp;
    }
  }
  //SPIFFS_CACHE_DBG("CACHE_GET: no cache for %04x\n", pix);
  return 0;
}

// allocates a new cached page and returns it, or null if all cache pages are busy
static spiffs_cache_page *ICACHE_FLASH_ATTR spiffs_cache_page_allocate(spiffs *fs) {
  spiffs_cache *cache = spiffs_get_cache(fs);
  if (cache->cpage_use_map == 0xffffffff) {
    // out of cache memory
    return 0;
  }
  int i;
  for (i = 0; i < cache->cpage_count; i++) {
    if ((cache->cpage_use_map & (1<<i)) == 0) {
      spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i);
      cache->cpage_use_map |= (1<<i);
      cp->last_access = cache->last_access;
      SPIFFS_CACHE_DBG("CACHE_ALLO: allocated cache page %i\n", i);
      return cp;
    }
  }
  // out of cache entries
  return 0;
}

// returns the cache page that this fd refers, or null if no cache page
spiffs_cache_page *ICACHE_FLASH_ATTR spiffs_cache_page_get_by_fd(spiffs *fs, spiffs_fd *fd) {
  spiffs_cache *cache = spiffs_get_cache(fs);

  if ((cache->cpage_use_map & cache->cpage_use_mask) == 0) {
    // all cpages free, no cpage cannot be assigned to obj_id
    return 0;
  }

  int i;
  for (i = 0; i < cache->cpage_count; i++) {
    spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i);
    if ((cache->cpage_use_map & (1<<i)) &&
        (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) &&
        cp->obj_id == fd->obj_id) {
      return cp;
    }
  }

  return 0;
}

// writes to spi flash and/or the cache
s32_t ICACHE_FLASH_ATTR
spiffs_phys_wr(
    spiffs *fs,
    u8_t op,
    spiffs_file fh,
    u32_t addr,
    u32_t len,
    u8_t *src) {
  (void)fh;
  spiffs_page_ix pix = SPIFFS_PADDR_TO_PAGE(fs, addr);
  spiffs_cache *cache = spiffs_get_cache(fs);
  spiffs_cache_page *cp =  spiffs_cache_page_get(fs, pix);

  if (cp && (op & SPIFFS_OP_COM_MASK) != SPIFFS_OP_C_WRTHRU) {
    // have a cache page
    // copy in data to cache page

    if ((op & SPIFFS_OP_COM_MASK) == SPIFFS_OP_C_DELE &&
        (op & SPIFFS_OP_TYPE_MASK) != SPIFFS_OP_T_OBJ_LU) {
      // page is being deleted, wipe from cache - unless it is a lookup page
      spiffs_cache_page_free(fs, cp->ix, 0);
      return fs->cfg.hal_write_f(addr, len, src);
    }

    u8_t *mem =  spiffs_get_cache_page(fs, cache, cp->ix);
    memcpy(&mem[SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr)], src, len);

    cache->last_access++;
    cp->last_access = cache->last_access;

    if (cp->flags && SPIFFS_CACHE_FLAG_WRTHRU) {
      // page is being updated, no write-cache, just pass thru
      return fs->cfg.hal_write_f(addr, len, src);
    } else {
      return SPIFFS_OK;
    }
  } else {
    // no cache page, no write cache - just write thru
    return fs->cfg.hal_write_f(addr, len, src);
  }
}

s32_t SPIFFS_write(spiffs *fs, spiffs_file fh, void *buf, u32_t len) {
  SPIFFS_API_CHECK_MOUNT(fs);
  SPIFFS_LOCK(fs);

  spiffs_fd *fd;
  s32_t res;
  u32_t offset;

  res = spiffs_fd_get(fs, fh, &fd);
  SPIFFS_API_CHECK_RES_UNLOCK(fs, res);

  if ((fd->flags & SPIFFS_WRONLY) == 0) {
    res = SPIFFS_ERR_NOT_WRITABLE;
    SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
  }

  offset = fd->fdoffset;

#if SPIFFS_CACHE_WR
  if (fd->cache_page == 0) {
    // see if object id is associated with cache already
    fd->cache_page = spiffs_cache_page_get_by_fd(fs, fd);
  }
#endif
  if (fd->flags & SPIFFS_APPEND) {
    if (fd->size == SPIFFS_UNDEFINED_LEN) {
      offset = 0;
    } else {
      offset = fd->size;
    }
#if SPIFFS_CACHE_WR
    if (fd->cache_page) {
      offset = MAX(offset, fd->cache_page->offset + fd->cache_page->size);
    }
#endif
  }

  SPIFFS_DBG("SPIFFS_write %d %04x offs:%d len %d\n", fh, fd->obj_id, offset, len);

#if SPIFFS_CACHE_WR
  if ((fd->flags & SPIFFS_DIRECT) == 0) {
    if (len < (s32_t)SPIFFS_CFG_LOG_PAGE_SZ(fs)) {
      // small write, try to cache it
      u8_t alloc_cpage = 1;
      if (fd->cache_page) {
        // have a cached page for this fd already, check cache page boundaries
        if (offset < fd->cache_page->offset || // writing before cache
            offset > fd->cache_page->offset + fd->cache_page->size || // writing after cache
            offset + len > fd->cache_page->offset + SPIFFS_CFG_LOG_PAGE_SZ(fs)) // writing beyond cache page
        {
          // boundary violation, write back cache first and allocate new
          SPIFFS_CACHE_DBG("CACHE_WR_DUMP: dumping cache page %d for fd %d:&04x, boundary viol, offs:%d size:%d\n",
              fd->cache_page->ix, fd->file_nbr, fd->obj_id, fd->cache_page->offset, fd->cache_page->size);
          res = spiffs_hydro_write(fs, fd,
              spiffs_get_cache_page(fs, spiffs_get_cache(fs), fd->cache_page->ix),
              fd->cache_page->offset, fd->cache_page->size);
          spiffs_cache_fd_release(fs, fd->cache_page);
        } else {
          // writing within cache
          alloc_cpage = 0;
        }
      }

      if (alloc_cpage) {
        fd->cache_page = spiffs_cache_page_allocate_by_fd(fs, fd);
        if (fd->cache_page) {
          fd->cache_page->offset = offset;
          fd->cache_page->size = 0;
          SPIFFS_CACHE_DBG("CACHE_WR_ALLO: allocating cache page %d for fd %d:%04x\n",
              fd->cache_page->ix, fd->file_nbr, fd->obj_id);
        }
      }

      if (fd->cache_page) {
        u32_t offset_in_cpage = offset - fd->cache_page->offset;
        SPIFFS_CACHE_DBG("CACHE_WR_WRITE: storing to cache page %d for fd %d:%04x, offs %d:%d len %d\n",
            fd->cache_page->ix, fd->file_nbr, fd->obj_id,
            offset, offset_in_cpage, len);
        spiffs_cache *cache = spiffs_get_cache(fs);
        u8_t *cpage_data = spiffs_get_cache_page(fs, cache, fd->cache_page->ix);
        c_memcpy(&cpage_data[offset_in_cpage], buf, len);
        fd->cache_page->size = MAX(fd->cache_page->size, offset_in_cpage + len);
        fd->fdoffset += len;
        SPIFFS_UNLOCK(fs);
        return len;
      } else {
        res = spiffs_hydro_write(fs, fd, buf, offset, len);
        SPIFFS_API_CHECK_RES(fs, res);
        fd->fdoffset += len;
        SPIFFS_UNLOCK(fs);
        return res;
      }
    } else {
      // big write, no need to cache it - but first check if there is a cached write already
      if (fd->cache_page) {
        // write back cache first
        SPIFFS_CACHE_DBG("CACHE_WR_DUMP: dumping cache page %d for fd %d:%04x, big write, offs:%d size:%d\n",
            fd->cache_page->ix, fd->file_nbr, fd->obj_id, fd->cache_page->offset, fd->cache_page->size);
        res = spiffs_hydro_write(fs, fd,
            spiffs_get_cache_page(fs, spiffs_get_cache(fs), fd->cache_page->ix),
//.........这里部分代码省略.........