Remove stale data binding outputs (tools/data-binding)

For each layout file containing data binding constructs, data binding
generates a corresponding layout info file and binding class files.

In an incremental build, there are 2 cases when layout info files/
binding class files get stale and need to be removed:
  1. Layout files previously containing data binding constructs were
     removed
  2. Layout files previously containing data binding constructs are now
     no longer containing them

Previously, only case #1 was handled and case #2 was missing. This CL
handles case #2.

Bug: 153711619
Test: New test in DataBindingIncrementalTest
Change-Id: I718b614222e5447503417b51d53486686c391273

2 files changed, 47 insertions, 4 deletions

diff --git a/compilerCommon/src/main/java/android/databinding/tool/LayoutXmlProcessor.java b/compilerCommon/src/main/java/android/databinding/tool/LayoutXmlProcessor.java
index a9fd885c..dd3cf1d5 100644
--- a/compilerCommon/src/main/java/android/databinding/tool/LayoutXmlProcessor.java
+++ b/compilerCommon/src/main/java/android/databinding/tool/LayoutXmlProcessor.java
@@ -150,6 +150,11 @@ public class LayoutXmlProcessor {
         mResourceBundle.addRemovedFile(input);
     }
 
+    /** Processes a layout file which does not contain data binding constructs. */
+    public void processFileWithNoDataBinding(@NonNull File file) {
+        mResourceBundle.addFileWithNoDataBinding(file);
+    }
+
     public boolean processSingleFile(@NonNull RelativizableFile input, @NonNull File output,
             boolean isViewBindingEnabled)
             throws ParserConfigurationException, SAXException, XPathExpressionException,
@@ -258,13 +263,26 @@ public class LayoutXmlProcessor {
     }
 
     public void writeLayoutInfoFiles(File xmlOutDir, JavaFileWriter writer) throws JAXBException {
+        // For each layout file, generate a corresponding layout info file
         for (ResourceBundle.LayoutFileBundle layout : mResourceBundle
                 .getAllLayoutFileBundlesInSource()) {
             writeXmlFile(writer, xmlOutDir, layout);
         }
-        for (File file : mResourceBundle.getRemovedFiles()) {
-            String exportFileName = generateExportFileName(file);
-            FileUtils.deleteQuietly(new File(xmlOutDir, exportFileName));
+
+        // Delete stale layout info files due to removed/changed layout files. There are 2 cases:
+        //   1. Layout files were removed
+        //   2. Layout files previously containing data binding constructs are now no longer
+        //      containing them (see bug 153711619). NOTE: This set of layout files is a subset of
+        //      mResourceBundle.getFilesWithNoDataBinding() because
+        //      mResourceBundle.getFilesWithNoDataBinding() may also contain layout files that do
+        //      not have a history or did not have data binding constructs in the previous build, in
+        //      which cases their associated layout info files don't exist.
+        List<File> staleLayoutFiles = new ArrayList<>(mResourceBundle.getRemovedFiles());
+        staleLayoutFiles.addAll(mResourceBundle.getFilesWithNoDataBinding());
+        for (File staleLayoutFile : staleLayoutFiles) {
+            File staleLayoutInfoFile = new File(xmlOutDir, generateExportFileName(staleLayoutFile));
+            // Delete quietly as the file may not exist (see comment above)
+            FileUtils.deleteQuietly(staleLayoutInfoFile);
         }
     }
 
diff --git a/compilerCommon/src/main/java/android/databinding/tool/store/ResourceBundle.java b/compilerCommon/src/main/java/android/databinding/tool/store/ResourceBundle.java
index d118fc55..7561175b 100644
--- a/compilerCommon/src/main/java/android/databinding/tool/store/ResourceBundle.java
+++ b/compilerCommon/src/main/java/android/databinding/tool/store/ResourceBundle.java
@@ -92,7 +92,23 @@ public class ResourceBundle implements Serializable {
 
     private Map<String, IncludedLayout> mDependencyBinders = new HashMap<>();
 
-    private List<File> mRemovedFiles = new ArrayList<File>();
+    /**
+     * Layout files that were removed. We track these files to delete stale layout info files that
+     * data binding generated in the previous build.
+     */
+    @NonNull private List<File> mRemovedFiles = new ArrayList<File>();
+
+    /**
+     * Layout files that exist in the current build but do not contain data binding constructs.
+     * These include:
+     *   1. Layout files that previously contained data binding constructs but are now no longer
+     *      containing them. We track these files to delete stale layout info files that data
+     *      binding generated in the previous build (see bug 153711619).
+     *   2. Layout files that do not have a history or did not have data binding constructs in the
+     *      previous build. We don't really need to track these files as there are no corresponding
+     *      stale layout info files to delete, but it's easier (and okay) to leave them here.
+     */
+    @NonNull private List<File> mFileWithNoDataBinding = new ArrayList<>();
 
     private final String viewDataBindingClass;
 
@@ -549,6 +565,15 @@ public class ResourceBundle implements Serializable {
         return mRemovedFiles;
     }
 
+    public void addFileWithNoDataBinding(@NonNull File file) {
+        mFileWithNoDataBinding.add(file);
+    }
+
+    @NonNull
+    public List<File> getFilesWithNoDataBinding() {
+        return new ArrayList<>(mFileWithNoDataBinding);
+    }
+
     @XmlAccessorType(XmlAccessType.NONE)
     @XmlRootElement(name = "Layout")
     public static class LayoutFileBundle implements Serializable, FileScopeProvider {