Avoid double buffering in Zend streams

Disable buffering in PHP streams, to avoid storing and copying the
file contents twice.

This will call stream_set_option() on custom stream wrapper as
well, so the method needs to be implemented to avoid a warning.

Zend/tests/bug38779.phpt

@@ -22,6 +22,9 @@ class Loader {
 	function stream_stat() {
 		return array('size' => strlen($this->data));
 	}
+	function stream_set_option($option, $arg1, $arg2) {
+		return false;
+	}
 }
 stream_wrapper_register('Loader', 'Loader');
 require 'Loader://qqq.php';

Zend/zend_stream.c

@@ -126,7 +126,7 @@ static size_t zend_stream_read(zend_file_handle *file_handle, char *buf, size_t
 ZEND_API int zend_stream_fixup(zend_file_handle *file_handle, char **buf, size_t *len) /* {{{ */
 {
 	size_t size;
-	zend_stream_type old_type;
+	zend_bool is_fp = 0;
 
 	if (file_handle->buf) {
 		*buf = file_handle->buf;
@@ -145,6 +145,7 @@ ZEND_API int zend_stream_fixup(zend_file_handle *file_handle, char **buf, size_t
 			return FAILURE;
 		}
 
+		is_fp = 1;
 		file_handle->type = ZEND_HANDLE_STREAM;
 		file_handle->handle.stream.handle = file_handle->handle.fp;
 		file_handle->handle.stream.isatty = isatty(fileno((FILE *)file_handle->handle.stream.handle));
@@ -158,10 +159,7 @@ ZEND_API int zend_stream_fixup(zend_file_handle *file_handle, char **buf, size_t
 		return FAILURE;
 	}
 
-	old_type = file_handle->type;
-	file_handle->type = ZEND_HANDLE_STREAM;  /* we might still be _FP but we need fsize() work */
-
-	if (old_type == ZEND_HANDLE_FP && !file_handle->handle.stream.isatty && size) {
+	if (is_fp && !file_handle->handle.stream.isatty && size) {
 		file_handle->buf = *buf = safe_emalloc(1, size, ZEND_MMAP_AHEAD);
 		file_handle->len = zend_stream_read(file_handle, *buf, size);
 	} else {

ext/standard/tests/file/fopencookie.phpt

@@ -76,6 +76,9 @@ class userstream {
 	function stream_stat() {
 		return array('size' => strlen($this->data));
 	}
+	function stream_set_option($option, $arg1, $arg2) {
+		return false;
+	}
 }
 
 stream_wrapper_register("cookietest", "userstream");

ext/standard/tests/file/include_streams.phpt

@@ -96,6 +96,9 @@ class mystream
 		}
 	}
 
+	function stream_set_option($option, $arg1, $arg2) {
+		return false;
+	}
 }
 
 if (!stream_wrapper_register("test", "mystream")) {

main/main.c

@@ -1594,6 +1594,8 @@ PHPAPI int php_stream_open_for_zend_ex(const char *filename, zend_file_handle *h
 		handle->handle.stream.closer = php_zend_stream_closer;
 		/* suppress warning if this stream is not explicitly closed */
 		php_stream_auto_cleanup(stream);
+		/* Disable buffering to avoid double buffering between PHP and Zend streams. */
+		php_stream_set_option(stream, PHP_STREAM_OPTION_READ_BUFFER, PHP_STREAM_BUFFER_NONE, NULL);
 
 		return SUCCESS;
 	}

sapi/phpdbg/tests/phpdbg_get_executable_stream_wrapper.phpt

@@ -59,6 +59,7 @@ final class StreamWrapper
     public function stream_close() : bool { return \fclose($this->stream); }
     public function stream_eof() : bool { return \feof($this->stream); }
     public function stream_stat() { return \fstat($this->stream); }
+    public function stream_set_option($option, $arg1, $arg2) { return false; }
 
     private $stream = false;
 }