File View Providers

A file view provider (FileViewProvider) manages access to multiple PSI trees within a single file.

For example, a JSPX page has a separate PSI tree for the Java code in it (PsiJavaFile), a separate tree for the XML code (XmlFile), and a separate tree for JSP as a whole (JspFile).

Each of the PSI trees covers the entire contents of the file and contains special "outer language elements" in the places where contents in a different language can be found.

A FileViewProvider instance corresponds to a single VirtualFile, a single Document, and can retrieve multiple PsiFile instances.

How do I get a FileViewProvider?

Context	API
PSI File	`PsiFile.getViewProvider()`
Virtual File	`PsiManager.getInstance(project).findViewProvider()`

What can I do with a FileViewProvider?

To get the set of all languages for which PSI trees exist in a file: fileViewProvider.getLanguages()
To get the PSI tree for a particular language: fileViewProvider.getPsi(language). For example, to get the PSI tree for XML, use fileViewProvider.getPsi(XMLLanguage.INSTANCE).
To find an element of a particular language at the specified offset in the file: fileViewProvider.findElementAt(offset, language)

How do I extend the FileViewProvider?

To create a file type that has multiple interspersing trees for different languages, a plugin must contain an extension to the com.intellij.fileType.fileViewProviderFactory extension point.

Implement FileViewProviderFactory and return your FileViewProvider implementation from createFileViewProvider() method.

<extensions defaultExtensionNs="com.intellij">
  <fileType.fileViewProviderFactory
      filetype="$FILE_TYPE$"
      implementationClass="com.example.MyFileViewProviderFactory"/>
</extensions>

Where $FILE_TYPE$ refers to the type of the file being created (for example, "JSF").

Last modified: 29 九月 2022