From 560bcb8653947d5d38fa9710c25b7eff6596b2fc Mon Sep 17 00:00:00 2001
From: Googler <noreply@google.com>
Date: Fri, 16 Jun 2017 15:02:53 +0200
Subject: ResourceFilter persists ordering of resources when filtering

Before this change, resource filtering by densities could rearrange the
ordering of resources. However, resource merging behavior is dependant on
resource ordering, so changing the order could lead to changed merge results.

Instead, ensure that the filtered resources appear in the same order as they
did in the original list of resources.

RELNOTES: none
PiperOrigin-RevId: 159219647
---
 .../build/lib/rules/android/ResourceFilter.java    | 53 ++++++++++++----------
 1 file changed, 28 insertions(+), 25 deletions(-)

(limited to 'src/main/java/com/google/devtools/build/lib/rules/android/ResourceFilter.java')

diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/ResourceFilter.java b/src/main/java/com/google/devtools/build/lib/rules/android/ResourceFilter.java
index e4bb33ee1e..2a504b360f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/ResourceFilter.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/ResourceFilter.java
@@ -33,10 +33,11 @@ import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.common.options.EnumConverter;
 import com.google.devtools.common.options.OptionsParsingException;
 import java.util.ArrayList;
-import java.util.Collection;
-import java.util.LinkedHashMap;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Filters resources based on their qualifiers.
@@ -305,12 +306,6 @@ public class ResourceFilter {
       return artifacts;
     }
 
-    /*
-     * Build an ImmutableSet rather than an ImmutableList to remove duplicate Artifacts in the case
-     * where one Artifact is the best option for multiple densities.
-     */
-    ImmutableSet.Builder<Artifact> builder = ImmutableSet.builder();
-
     List<BestArtifactsForDensity> bestArtifactsForAllDensities = new ArrayList<>();
     for (Density density : getDensities(ruleErrorConsumer)) {
       bestArtifactsForAllDensities.add(new BestArtifactsForDensity(ruleErrorConsumer, density));
@@ -318,6 +313,7 @@ public class ResourceFilter {
 
     ImmutableList<FolderConfiguration> folderConfigs = getConfigurationFilters(ruleErrorConsumer);
 
+    Set<Artifact> keptArtifactsNotFilteredByDensity = new HashSet<>();
     for (Artifact artifact : artifacts) {
       FolderConfiguration config = getConfigForArtifact(ruleErrorConsumer, artifact);
 
@@ -329,7 +325,7 @@ public class ResourceFilter {
       }
 
       if (!shouldFilterByDensity(artifact)) {
-        builder.add(artifact);
+        keptArtifactsNotFilteredByDensity.add(artifact);
         continue;
       }
 
@@ -338,23 +334,33 @@ public class ResourceFilter {
       }
     }
 
-    for (BestArtifactsForDensity bestArtifactsForDensity : bestArtifactsForAllDensities) {
-      builder.addAll(bestArtifactsForDensity.get());
-    }
-
-    ImmutableSet<Artifact> keptArtifacts = builder.build();
+    // Build the output by iterating through the input so that contents of both have the same order.
+    ImmutableList.Builder<Artifact> builder = ImmutableList.builder();
     for (Artifact artifact : artifacts) {
-      if (keptArtifacts.contains(artifact)) {
-        continue;
+
+      boolean kept = false;
+      if (keptArtifactsNotFilteredByDensity.contains(artifact)) {
+        builder.add(artifact);
+        kept = true;
+      } else {
+        for (BestArtifactsForDensity bestArtifactsForDensity : bestArtifactsForAllDensities) {
+          if (bestArtifactsForDensity.contains(artifact)) {
+            builder.add(artifact);
+            kept = true;
+            break;
+          }
+        }
       }
 
-      String parentDir = artifact.getPath().getParentDirectory().getBaseName();
-      filteredResources.add(parentDir + "/" + artifact.getFilename());
+      if (!kept) {
+        String parentDir = artifact.getPath().getParentDirectory().getBaseName();
+        filteredResources.add(parentDir + "/" + artifact.getFilename());
+      }
     }
 
     // TODO(asteinb): We should only build a new list if some artifacts were filtered out. If
     // nothing was filtered, we can be more efficient by returning the original list instead.
-    return keptArtifacts.asList();
+    return builder.build();
   }
 
   /**
@@ -364,9 +370,7 @@ public class ResourceFilter {
   private static class BestArtifactsForDensity {
     private final RuleErrorConsumer ruleErrorConsumer;
     private final Density desiredDensity;
-
-    // Use a LinkedHashMap to preserve determinism.
-    private final Map<String, Artifact> nameAndConfigurationToBestArtifact = new LinkedHashMap<>();
+    private final Map<String, Artifact> nameAndConfigurationToBestArtifact = new HashMap<>();
 
     public BestArtifactsForDensity(RuleErrorConsumer ruleErrorConsumer, Density density) {
       this.ruleErrorConsumer = ruleErrorConsumer;
@@ -392,9 +396,8 @@ public class ResourceFilter {
       }
     }
 
-    /** @return the collection of best Artifacts for this density. */
-    public Collection<Artifact> get() {
-      return nameAndConfigurationToBestArtifact.values();
+    public boolean contains(Artifact artifact) {
+      return nameAndConfigurationToBestArtifact.containsValue(artifact);
     }
 
     /**
-- 
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