Issue #1081 has been updated by Yusuke Endoh.


Hi,

> Please add a File::write() convenience method to the core Ruby API.

I have written a patch.  The API is similar to File.read except string:

  File.write(path, string[, offset])            #=> length written
  File.write(path, string[, offset], open_args) #=> length written

If offset is given, the file is not truncated.  Otherwise, truncated.

  $ ./ruby -e 'File.write("foo", "foo\nbar\nbaz\n")' && cat foo
  foo
  bar
  baz

  $ ./ruby -e 'File.write("foo", "BAR", 4)' && cat foo
  foo
  BAR
  baz

  $ ./ruby -e 'File.write("foo", "FOO\n")' && cat foo
  FOO

  $ ./ruby -e 'File.write("foo", "あいうえお", mode: "w", encoding: "EUC-JP")' && nkf -Ew foo
  あいうえお

I'll commit the patch if anyone says objection.


diff --git a/io.c b/io.c
index 8026ea3..08d4988 100644
--- a/io.c
+++ b/io.c
@@ -7701,7 +7701,7 @@ struct foreach_arg {
 };
 
 static void
-open_key_args(int argc, VALUE *argv, struct foreach_arg *arg)
+open_key_args_with_opt(int argc, VALUE *argv, struct foreach_arg *arg, int mandatory_argc, int default_mode, int default_perm)
 {
     VALUE opt, v;
 
@@ -7709,9 +7709,9 @@ open_key_args(int argc, VALUE *argv, struct foreach_arg *arg)
     arg->io = 0;
     arg->argc = argc - 1;
     arg->argv = argv + 1;
-    if (argc == 1) {
+    if (argc == mandatory_argc) {
       no_key:
-	arg->io = rb_io_open(argv[0], INT2NUM(O_RDONLY), INT2FIX(0666), Qnil);
+	arg->io = rb_io_open(argv[0], INT2NUM(default_mode), INT2FIX(default_perm), Qnil);
 	return;
     }
     opt = pop_last_hash(&arg->argc, arg->argv);
@@ -7736,9 +7736,23 @@ open_key_args(int argc, VALUE *argv, struct foreach_arg *arg)
 	rb_ary_clear(args);	/* prevent from GC */
 	return;
     }
+    if (default_mode != O_RDONLY && NIL_P(rb_hash_aref(opt, sym_mode))) {
+	opt = rb_hash_dup(opt);
+	rb_hash_aset(opt, sym_mode, INT2NUM(default_mode));
+    }
+    if (default_perm != 0666 && NIL_P(rb_hash_aref(opt, sym_perm))) {
+	opt = rb_hash_dup(opt);
+	rb_hash_aset(opt, sym_perm, INT2FIX(default_perm));
+    }
     arg->io = rb_io_open(argv[0], Qnil, Qnil, opt);
 }
 
+static void
+open_key_args(int argc, VALUE *argv, struct foreach_arg *arg)
+{
+    open_key_args_with_opt(argc, argv, arg, 1, O_RDONLY, 0666);
+}
+
 static VALUE
 io_s_foreach(struct foreach_arg *arg)
 {
@@ -7826,6 +7840,16 @@ io_s_read(struct foreach_arg *arg)
     return io_read(arg->argc, arg->argv, arg->io);
 }
 
+struct write_arg {
+    VALUE io, str;
+};
+
+static VALUE
+io_s_write(struct write_arg *arg)
+{
+    return io_write(arg->io, arg->str, 0);
+}
+
 struct seek_arg {
     VALUE io;
     VALUE offset;
@@ -7833,7 +7857,7 @@ struct seek_arg {
 };
 
 static VALUE
-seek_before_read(struct seek_arg *arg)
+seek_before_access(struct seek_arg *arg)
 {
     rb_io_binmode(arg->io);
     return rb_io_seek(arg->io, arg->offset, arg->mode);
@@ -7844,7 +7868,7 @@ seek_before_read(struct seek_arg *arg)
  *     IO.read(name, [length [, offset]] )   => string
  *     IO.read(name, [length [, offset]], open_args)   => string
  *
- *  Opens the file, optionally seeks to the given offset, then returns
+ *  Opens the file, optionally seeks to the given <i>offset</i>, then returns
  *  <i>length</i> bytes (defaulting to the rest of the file).
  *  <code>read</code> ensures the file is closed before returning.
  *
@@ -7886,7 +7910,7 @@ rb_io_s_read(int argc, VALUE *argv, VALUE io)
 	sarg.io = arg.io;
 	sarg.offset = offset;
 	sarg.mode = SEEK_SET;
-	rb_protect((VALUE (*)(VALUE))seek_before_read, (VALUE)&sarg, &state);
+	rb_protect((VALUE (*)(VALUE))seek_before_access, (VALUE)&sarg, &state);
 	if (state) {
 	    rb_io_close(arg.io);
 	    rb_jump_tag(state);
@@ -7900,9 +7924,9 @@ rb_io_s_read(int argc, VALUE *argv, VALUE io)
  *  call-seq:
  *     IO.binread(name, [length [, offset]] )   => string
  *
- *  Opens the file, optionally seeks to the given offset, then returns
+ *  Opens the file, optionally seeks to the given <i>offset</i>, then returns
  *  <i>length</i> bytes (defaulting to the rest of the file).
- *  <code>read</code> ensures the file is closed before returning.
+ *  <code>binread</code> ensures the file is closed before returning.
  *  The open mode would be "rb:ASCII-8BIT".
  *
  *     IO.binread("testfile")           #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
@@ -7928,6 +7952,117 @@ rb_io_s_binread(int argc, VALUE *argv, VALUE io)
     return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
 }
 
+/*
+ *  call-seq:
+ *     IO.write(name, string, [offset] )   => fixnum
+ *     IO.write(name, string, [offset], open_args )   => fixnum
+ *
+ *  Opens the file, optionally seeks to the given <i>offset</i>, writes
+ *  <i>string</i>, then returns the length written.
+ *  <code>write</code> ensures the file is closed before returning.
+ *  If <i>offset</i> is not given, the file is truncated.  Otherwise,
+ *  it is not truncated.
+ *
+ *  If the last argument is a hash, it specifies option for internal
+ *  open().  The key would be the following.  open_args: is exclusive
+ *  to others.
+ *
+ *   encoding: string or encoding
+ *
+ *    specifies encoding of the read string.  encoding will be ignored
+ *    if length is specified.
+ *
+ *   mode: string
+ *
+ *    specifies mode argument for open().  it should start with "w" or "a" or "r+"
+ *    otherwise it would cause error.
+ *
+ *   perm: fixnum
+ *
+ *    specifies perm argument for open().
+ *
+ *   open_args: array of strings
+ *
+ *    specifies arguments for open() as an array.
+ *
+ *     IO.write("testfile", "0123456789")      #=> "0123456789"
+ *     IO.write("testfile", "0123456789", 20)  #=> "This is line one\nThi0123456789two\nThis is line three\nAnd so on...\n"
+ */
+
+static VALUE
+rb_io_s_write(int argc, VALUE *argv, VALUE io)
+{
+    VALUE offset;
+    struct foreach_arg arg;
+    struct write_arg warg;
+    int mode = O_WRONLY | O_CREAT, mandatory_argc;
+
+    rb_scan_args(argc, argv, "22", NULL, &warg.str, &offset, NULL);
+    if (!NIL_P(offset) && FIXNUM_P(offset)) {
+	mandatory_argc = 3;
+    }
+    else {
+	mode |= O_TRUNC;
+	mandatory_argc = 2;
+    }
+    open_key_args_with_opt(argc, argv, &arg, mandatory_argc, mode, 0666);
+    if (NIL_P(arg.io)) return Qnil;
+    if (!NIL_P(offset) && FIXNUM_P(offset)) {
+	struct seek_arg sarg;
+	int state = 0;
+	sarg.io = arg.io;
+	sarg.offset = offset;
+	sarg.mode = SEEK_SET;
+	rb_protect((VALUE (*)(VALUE))seek_before_access, (VALUE)&sarg, &state);
+	if (state) {
+	    rb_io_close(arg.io);
+	    rb_jump_tag(state);
+	}
+	if (arg.argc == 2) arg.argc = 1;
+    }
+    warg.io = arg.io;
+    return rb_ensure(io_s_write, (VALUE)&warg, rb_io_close, arg.io);
+}
+
+/*
+ *  call-seq:
+ *     IO.binwrite(name, string, [offset] )   => fixnum
+ *
+ *  Opens the file, optionally seeks to the given <i>offset</i>, write
+ *  <i>string</i> then returns the length written.
+ *  <code>binwrite</code> ensures the file is closed before returning.
+ *  The open mode would be "wb:ASCII-8BIT".
+ *  If <i>offset</i> is not given, the file is truncated.  Otherwise,
+ *  it is not truncated.
+ *
+ *     IO.binwrite("testfile", "0123456789")      #=> "0123456789"
+ *     IO.binwrite("testfile", "0123456789", 20)  #=> "This is line one\nThi0123456789two\nThis is line three\nAnd so on...\n"
+ */
+
+static VALUE
+rb_io_s_binwrite(int argc, VALUE *argv, VALUE io)
+{
+    VALUE offset;
+    const char *mode;
+    struct write_arg warg;
+
+    rb_scan_args(argc, argv, "21", NULL, &warg.str, &offset);
+    if (!NIL_P(offset)) {
+	NUM2OFFT(offset);
+	mode = "ab:ASCII-8BIT";
+    }
+    else {
+	mode = "wb:ASCII-8BIT";
+    }
+    FilePathValue(argv[0]);
+    warg.io = rb_io_open(argv[0], rb_str_new_cstr(mode), Qnil, Qnil);
+    if (NIL_P(warg.io)) return Qnil;
+    if (!NIL_P(offset)) {
+	rb_io_seek(warg.io, offset, SEEK_SET);
+    }
+    return rb_ensure(io_s_write, (VALUE)&warg, rb_io_close, warg.io);
+}
+
 struct copy_stream_struct {
     VALUE src;
     VALUE dst;
@@ -9731,6 +9866,8 @@ Init_IO(void)
     rb_define_singleton_method(rb_cIO, "readlines", rb_io_s_readlines, -1);
     rb_define_singleton_method(rb_cIO, "read", rb_io_s_read, -1);
     rb_define_singleton_method(rb_cIO, "binread", rb_io_s_binread, -1);
+    rb_define_singleton_method(rb_cIO, "write", rb_io_s_write, -1);
+    rb_define_singleton_method(rb_cIO, "binwrite", rb_io_s_binwrite, -1);
     rb_define_singleton_method(rb_cIO, "select", rb_f_select, -1);
     rb_define_singleton_method(rb_cIO, "pipe", rb_io_s_pipe, -1);
     rb_define_singleton_method(rb_cIO, "try_convert", rb_io_s_try_convert, 1);
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 5fc3b13..6ea128a 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1512,4 +1512,34 @@ End
     t.close
     assert_raise(IOError) {t.binmode}
   end
+
+  def test_s_write
+    t = Tempfile.new("foo")
+    path = t.path
+    t.close(false)
+    File.write(path, "foo\nbar\nbaz")
+    assert("foo\nbar\nbaz", File.read(path))
+    File.write(path, "FOO", 0)
+    assert("FOO\nbar\nbaz", File.read(path))
+    File.write(path, "BAR")
+    assert("BAR", File.read(path))
+    File.write(path, "\u{3042}", mode: "w", encoding: "EUC-JP")
+    assert("\u{3042}".encode("EUC-JP"), File.read(path, encoding: "EUC-JP"))
+    t.unlink
+  end
+
+  def test_s_binwrite
+    t = Tempfile.new("foo")
+    path = t.path
+    t.close(false)
+    File.binwrite(path, "foo\nbar\nbaz")
+    assert("foo\nbar\nbaz", File.read(path))
+    File.binwrite(path, "FOO", 0)
+    assert("FOO\nbar\nbaz", File.read(path))
+    File.binwrite(path, "BAR")
+    assert("BAR", File.read(path))
+    File.binwrite(path, "\u{3042}")
+    assert("\u{3042}", File.read(path, encoding: "EUC-JP"))
+    t.unlink
+  end
 end

-- 
Yusuke Endoh <mame / tsg.ne.jp>
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http://redmine.ruby-lang.org/issues/show/1081

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