Craft\AmFormsService::getPathForAsset PHP Method

    public function getPathForAsset($asset)
    {
        // Do we know the source folder path?
        if (!isset($this->_assetFolders[$asset->folderId])) {
            $assetFolder = craft()->assets->getFolderById($asset->folderId);
            $assetSource = $assetFolder->getSource();
            $assetSettings = $assetSource->settings;
            if ($assetFolder->path) {
                $assetSettings['path'] = $assetSettings['path'] . $assetFolder->path;
            }
            $this->_assetFolders[$asset->folderId] = $assetSettings['path'];
        }
        return craft()->config->parseEnvironmentString($this->_assetFolders[$asset->folderId]);
    }