get_compat_media_markup

get_compat_media_markup:这个WordPress函数用来检索与当前版本的WordPress不兼容的媒体文件的HTML标记。它把媒体文件的URL作为它的唯一参数，并返回相应的HTML标记，可以用来把文件嵌入到一个文章或页面中。

获取兼容的媒体标记。

function get_compat_media_markup( $attachment_id, $args = null ) {
	$post = get_post( $attachment_id );

	$default_args = array(
		'errors'   => null,
		'in_modal' => false,
	);

	$user_can_edit = current_user_can( 'edit_post', $attachment_id );

	$args = wp_parse_args( $args, $default_args );

	/** This filter is documented in wp-admin/includes/media.php */
	$args = apply_filters( 'get_media_item_args', $args );

	$form_fields = array();

	if ( $args['in_modal'] ) {
		foreach ( get_attachment_taxonomies( $post ) as $taxonomy ) {
			$t = (array) get_taxonomy( $taxonomy );

			if ( ! $t['public'] || ! $t['show_ui'] ) {
				continue;
			}

			if ( empty( $t['label'] ) ) {
				$t['label'] = $taxonomy;
			}

			if ( empty( $t['args'] ) ) {
				$t['args'] = array();
			}

			$terms = get_object_term_cache( $post->ID, $taxonomy );

			if ( false === $terms ) {
				$terms = wp_get_object_terms( $post->ID, $taxonomy, $t['args'] );
			}

			$values = array();

			foreach ( $terms as $term ) {
				$values[] = $term->slug;
			}

			$t['value']    = implode( ', ', $values );
			$t['taxonomy'] = true;

			$form_fields[ $taxonomy ] = $t;
		}
	}

	/*
	 * Merge default fields with their errors, so any key passed with the error
	 * (e.g. 'error', 'helps', 'value') will replace the default.
	 * The recursive merge is easily traversed with array casting:
	 * foreach ( (array) $things as $thing )
	 */
	$form_fields = array_merge_recursive( $form_fields, (array) $args['errors'] );

	/** This filter is documented in wp-admin/includes/media.php */
	$form_fields = apply_filters( 'attachment_fields_to_edit', $form_fields, $post );

	unset(
		$form_fields['image-size'],
		$form_fields['align'],
		$form_fields['image_alt'],
		$form_fields['post_title'],
		$form_fields['post_excerpt'],
		$form_fields['post_content'],
		$form_fields['url'],
		$form_fields['menu_order'],
		$form_fields['image_url']
	);

	/** This filter is documented in wp-admin/includes/media.php */
	$media_meta = apply_filters( 'media_meta', '', $post );

	$defaults = array(
		'input'         => 'text',
		'required'      => false,
		'value'         => '',
		'extra_rows'    => array(),
		'show_in_edit'  => true,
		'show_in_modal' => true,
	);

	$hidden_fields = array();

	$item = '';

	foreach ( $form_fields as $id => $field ) {
		if ( '_' === $id[0] ) {
			continue;
		}

		$name    = "attachments[$attachment_id][$id]";
		$id_attr = "attachments-$attachment_id-$id";

		if ( ! empty( $field['tr'] ) ) {
			$item .= $field['tr'];
			continue;
		}

		$field = array_merge( $defaults, $field );

		if ( ( ! $field['show_in_edit'] && ! $args['in_modal'] ) || ( ! $field['show_in_modal'] && $args['in_modal'] ) ) {
			continue;
		}

		if ( 'hidden' === $field['input'] ) {
			$hidden_fields[ $name ] = $field['value'];
			continue;
		}

		$readonly      = ! $user_can_edit && ! empty( $field['taxonomy'] ) ? " readonly='readonly' " : '';
		$required      = $field['required'] ? ' ' . wp_required_field_indicator() : '';
		$required_attr = $field['required'] ? ' required' : '';
		$class         = 'compat-field-' . $id;
		$class        .= $field['required'] ? ' form-required' : '';

		$item .= "tt<tr class='$class'>";
		$item .= "ttt<th scope='row' class='label'><label for='$id_attr'><span class='alignleft'>{$field['label']}</span>$required<br class='clear' /></label>";
		$item .= "</th>nttt<td class='field'>";

		if ( ! empty( $field[ $field['input'] ] ) ) {
			$item .= $field[ $field['input'] ];
		} elseif ( 'textarea' === $field['input'] ) {
			if ( 'post_content' === $id && user_can_richedit() ) {
				// sanitize_post() skips the post_content when user_can_richedit.
				$field['value'] = htmlspecialchars( $field['value'], ENT_QUOTES );
			}
			$item .= "<textarea id='$id_attr' name='$name'{$required_attr}>" . $field['value'] . '</textarea>';
		} else {
			$item .= "<input type='text' class='text' id='$id_attr' name='$name' value='" . esc_attr( $field['value'] ) . "' $readonly{$required_attr} />";
		}

		if ( ! empty( $field['helps'] ) ) {
			$item .= "<p class='help'>" . implode( "</p>n<p class='help'>", array_unique( (array) $field['helps'] ) ) . '</p>';
		}

		$item .= "</td>ntt</tr>n";

		$extra_rows = array();

		if ( ! empty( $field['errors'] ) ) {
			foreach ( array_unique( (array) $field['errors'] ) as $error ) {
				$extra_rows['error'][] = $error;
			}
		}

		if ( ! empty( $field['extra_rows'] ) ) {
			foreach ( $field['extra_rows'] as $class => $rows ) {
				foreach ( (array) $rows as $html ) {
					$extra_rows[ $class ][] = $html;
				}
			}
		}

		foreach ( $extra_rows as $class => $rows ) {
			foreach ( $rows as $html ) {
				$item .= "tt<tr><td></td><td class='$class'>$html</td></tr>n";
			}
		}
	}

	if ( ! empty( $form_fields['_final'] ) ) {
		$item .= "tt<tr class='final'><td colspan='2'>{$form_fields['_final']}</td></tr>n";
	}

	if ( $item ) {
		$item = '<p class="media-types media-types-required-info">' .
			wp_required_field_message() .
			'</p>' .
			'<table class="compat-attachment-fields">' . $item . '</table>';
	}

	foreach ( $hidden_fields as $hidden_field => $value ) {
		$item .= '<input type="hidden" name="' . esc_attr( $hidden_field ) . '" value="' . esc_attr( $value ) . '" />' . "n";
	}

	if ( $item ) {
		$item = '<input type="hidden" name="attachments[' . $attachment_id . '][menu_order]" value="' . esc_attr( $post->menu_order ) . '" />' . $item;
	}

	return array(
		'item' => $item,
		'meta' => $media_meta,
	);
}