As in MRI, use target file's size when reading it entirely.

jruby · Oct 6, 2015 · e5e7eb9 · e5e7eb9
1 parent 3c3055d
commit e5e7eb9
Showing 2 changed files with 11 additions and 19 deletions.
diff --git a/core/src/main/java/org/jruby/RubyIO.java b/core/src/main/java/org/jruby/RubyIO.java
@@ -2984,7 +2984,7 @@ public IRubyObject read(ThreadContext context, IRubyObject length, IRubyObject s
             boolean locked = fptr.lock();
             try {
                 fptr.checkCharReadable(context);
-                return fptr.readAll(context, 0, str);
+                return fptr.readAll(context, fptr.remainSize(), str);
             } finally {
                 if (locked) fptr.unlock();
             }

diff --git a/core/src/main/java/org/jruby/util/io/OpenFile.java b/core/src/main/java/org/jruby/util/io/OpenFile.java
@@ -2620,28 +2620,20 @@ private void SET_TEXT_MODE() {
     }
 
     public int remainSize() {
-        FileStat st;
         int siz = READ_DATA_PENDING_COUNT();
+        long size;
         long pos;
 
-        // MRI does all this presumably to read more of the file right away, but
-        // I believe the logic that uses this is ok with just pending read plus buf size.
-
-//        if (fstat(fptr -> fd, & st)==0 && S_ISREG(st.st_mode))
-//        {
-//            if (io_fflush(fptr) < 0)
-//                rb_sys_fail(0);
-//            pos = lseek(fptr -> fd, 0, SEEK_CUR);
-//            if (st.st_size >= pos && pos >= 0) {
-//                siz += st.st_size - pos;
-//                if (siz > LONG_MAX) {
-//                    rb_raise(rb_eIOError, "file too big for single read");
-//                }
-//            }
-//        }
-//        else {
+        if ((size = posix.size(fd)) >= 0 &&
+                (pos = posix.lseek(fd, 0, PosixShim.SEEK_CUR)) >= 0 &&
+                size > pos) {
+            if (siz + (size - pos) > Integer.MAX_VALUE) {
+                throw runtime.newIOError("file too big for single read");
+            }
+            siz += size - pos;
+        } else {
             siz += BUFSIZ;
-//        }
+        }
         return siz;
     }