Style improvements

Author: JoeOsborn

src/lib/libfetchfs.js

@@ -8,9 +8,8 @@ addToLibrary({
   $FETCHFS__deps: ['$stringToUTF8OnStack', 'wasmfs_create_fetch_backend'],
   $FETCHFS: {
     createBackend(opts) {
-      opts.base_url ??= "";
       return withStackSave(() => {
-        return _wasmfs_create_fetch_backend(stringToUTF8OnStack(opts.base_url), opts.chunkSize | 0);
+        return _wasmfs_create_fetch_backend(stringToUTF8OnStack(opts.base_url ?? ""), opts.chunkSize | 0);
       });
     },
   },

src/lib/libwasmfs_fetch.js

@@ -37,7 +37,7 @@ addToLibrary({
       }
       var chunkSize = __wasmfs_fetch_get_chunk_size(file);
       offset ??= 0;
-      len = len || chunkSize;
+      len ??= chunkSize;
       var firstChunk = (offset / chunkSize) | 0;
       var lastChunk = ((offset+len) / chunkSize) | 0;
       if (!(file in wasmFS$JSMemoryRanges)) {
@@ -46,7 +46,11 @@ addToLibrary({
            fileInfo.headers.has("Content-Length") &&
            fileInfo.headers.get("Accept-Ranges") == "bytes" &&
            (parseInt(fileInfo.headers.get("Content-Length")) > chunkSize*2)) {
-          wasmFS$JSMemoryRanges[file] = {size:parseInt(fileInfo.headers.get("Content-Length")), chunks:[], chunkSize:chunkSize};
+          wasmFS$JSMemoryRanges[file] = {
+            size:parseInt(fileInfo.headers.get("Content-Length")),
+            chunks:[],
+            chunkSize:chunkSize
+          };
         } else {
           // may as well/forced to download the whole file
           var wholeFileReq = await fetch(url);
@@ -55,7 +59,11 @@ addToLibrary({
           }
           var wholeFileData = new Uint8Array(await wholeFileReq.arrayBuffer());
           var text = new TextDecoder().decode(wholeFileData);
-          wasmFS$JSMemoryRanges[file] = {size:wholeFileData.byteLength, chunks:[wholeFileData], chunkSize:wholeFileData.byteLength};
+          wasmFS$JSMemoryRanges[file] = {
+            size:wholeFileData.byteLength,
+            chunks:[wholeFileData],
+            chunkSize:wholeFileData.byteLength
+          };
           return Promise.resolve();
         }
       }

system/include/emscripten/wasmfs.h

@@ -59,6 +59,11 @@ backend_t wasmfs_create_memory_backend(void);
 // and ending with whatever the file's path is relative to where the
 // fetchfs directory is mounted.
 //
+// Individual range requests will be no bigger than chunk_size, and will
+// be aligned to boundaries of chunk_size.  Files smaller than chunk_size
+// will be downloaded all at once.
+//
+// If chunk_size is 0, a reasonable default value will be used.
 //
 // Note: this cannot be called on the browser main thread because it might
 // deadlock while waiting for its dedicated worker thread to be spawned.
@@ -71,7 +76,7 @@ backend_t wasmfs_create_memory_backend(void);
 // thread.
 //
 backend_t wasmfs_create_fetch_backend(const char* base_url __attribute__((nonnull)),
-                                      uint32_t chunkSize);
+                                      uint32_t chunk_size);
 
 backend_t wasmfs_create_node_backend(const char* root __attribute__((nonnull)));
 

system/lib/wasmfs/backends/fetch_backend.cpp

@@ -94,7 +94,7 @@ std::shared_ptr<Directory> FetchBackend::createDirectory(mode_t mode) {
 }
 
 const std::string FetchBackend::getFileURL(const std::string& filePath) {
-  if(filePath == "") {
+  if (filePath == "") {
     return baseUrl;
   }
   return baseUrl + "/" + filePath;

test/wasmfs/wasmfs_fetch.c

@@ -43,7 +43,7 @@ void check_file(int fd, const char* content) {
 void test_url_relative() {
   printf("Running %s...\n", __FUNCTION__);
 
-  backend_t backend2 = wasmfs_create_fetch_backend("test.txt",0);
+  backend_t backend2 = wasmfs_create_fetch_backend("test.txt", 0);
   int fd = wasmfs_create_file("/file_rel", 0777, backend2);
   check_file(fd, "fetch 2");
   assert(close(fd) == 0);
@@ -57,7 +57,7 @@ void test_url_absolute() {
   char url[200];
   snprintf(url, sizeof(url), "%s%s", url_orig, file_name);
 
-  backend_t backend = wasmfs_create_fetch_backend(url,0);
+  backend_t backend = wasmfs_create_fetch_backend(url, 0);
   int fd = wasmfs_create_file(file_name, 0777, backend);
   check_file(fd, "fetch 2");
   assert(close(fd) == 0);
@@ -70,7 +70,7 @@ void test_directory_abs() {
   char url[200];
   snprintf(url, sizeof(url), "%s%s", url_orig, dir_path);
 
-  backend_t backend = wasmfs_create_fetch_backend(url,0);
+  backend_t backend = wasmfs_create_fetch_backend(url, 0);
   int res = wasmfs_create_directory(dir_path, 0777, backend);
   if (errno)
     perror("wasmfs_create_directory");
@@ -101,7 +101,7 @@ void test_directory_abs() {
 
 void test_default() {
   printf("Running %s...\n", __FUNCTION__);
-  backend_t backend = wasmfs_create_fetch_backend("data.dat",0);
+  backend_t backend = wasmfs_create_fetch_backend("data.dat", 0);
 
   // Create a file in that backend.
   int fd = wasmfs_create_file("/testfile", 0777, backend);
@@ -137,7 +137,7 @@ void test_small_reads() {
   char expected[] = "hello";
   size_t size = 5;
 
-  backend_t backend = wasmfs_create_fetch_backend("small.dat",0);
+  backend_t backend = wasmfs_create_fetch_backend("small.dat", 0);
   int fd = wasmfs_create_file("/testfile3", 0777, backend);
   char buf[size + 1];
   for (size_t i = 0; i < size; i++) {