Merge pull request #2945 from aidanhs/aphs-ungetc-nodefs-fixes

Fix ungetc on nodefs

src/library_fs.js

@@ -1068,7 +1068,9 @@ mergeInto(LibraryManager.library, {
       if (!stream.seekable || !stream.stream_ops.llseek) {
         throw new FS.ErrnoError(ERRNO_CODES.ESPIPE);
       }
-      return stream.stream_ops.llseek(stream, offset, whence);
+      stream.position = stream.stream_ops.llseek(stream, offset, whence);
+      stream.ungotten = [];
+      return stream.position;
     },
     read: function(stream, buffer, offset, length, position) {
       if (length < 0 || position < 0) {

src/library_memfs.js

@@ -335,8 +335,6 @@ mergeInto(LibraryManager.library, {
         if (position < 0) {
           throw new FS.ErrnoError(ERRNO_CODES.EINVAL);
         }
-        stream.ungotten = [];
-        stream.position = position;
         return position;
       },
       allocate: function(stream, offset, length) {

src/library_nodefs.js

@@ -233,6 +233,7 @@ mergeInto(LibraryManager.library, {
         }
       },
       read: function (stream, buffer, offset, length, position) {
+        if (length === 0) return 0; // node errors on 0 length reads
         // FIXME this is terrible.
         var nbuffer = new Buffer(length);
         var res;
@@ -278,7 +279,6 @@ mergeInto(LibraryManager.library, {
           throw new FS.ErrnoError(ERRNO_CODES.EINVAL);
         }
 
-        stream.position = position;
         return position;
       }
     }

tests/stdio/test_fgetc_ungetc.c

@@ -5,6 +5,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <emscripten.h>
 
 static void create_file(const char *path, const char *buffer, int mode) {
   int fd = open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
@@ -17,11 +18,11 @@ static void create_file(const char *path, const char *buffer, int mode) {
 }
 
 void setup() {
-  create_file("file.txt", "cd", 0666);
+  create_file("/tmp/file.txt", "cd", 0666);
 }
 
 void cleanup() {
-  unlink("file.txt");
+  unlink("/tmp/file.txt");
 }
 
 void test() {
@@ -29,7 +30,7 @@ void test() {
   int err;
   char buffer[256];
 
-  file = fopen("file.txt", "r");
+  file = fopen("/tmp/file.txt", "r");
   assert(file);
 
   // pushing EOF always returns EOF
@@ -82,6 +83,11 @@ void test() {
 }
 
 int main() {
+#ifdef NODEFS
+  EM_ASM(FS.mount(NODEFS, { root: '.' }, '/tmp'));
+#elif MEMFS
+  EM_ASM(FS.mount(MEMFS, {}, '/tmp'));
+#endif
   atexit(cleanup);
   signal(SIGABRT, cleanup);
   setup();

tests/test_core.py

@@ -4276,8 +4276,13 @@ def process(filename):
       self.do_run_from_file(src, output)
 
   def test_fgetc_ungetc(self):
-    src = open(path_from_root('tests', 'stdio', 'test_fgetc_ungetc.c'), 'r').read()
-    self.do_run(src, 'success', force_c=True)
+    self.clear()
+    if not self.is_emscripten_abi(): return self.skip('asmjs-unknown-emscripten needed for inline js')
+    orig_compiler_opts = Building.COMPILER_TEST_OPTS[:]
+    for fs in ['MEMFS', 'NODEFS']:
+        src = open(path_from_root('tests', 'stdio', 'test_fgetc_ungetc.c'), 'r').read()
+        Building.COMPILER_TEST_OPTS = orig_compiler_opts + ['-D' + fs]
+        self.do_run(src, 'success', force_c=True, js_engines=[NODE_JS])
 
   def test_fgetc_unsigned(self):
     if self.emcc_args is None: return self.skip('requires emcc')