commit c744ae8aca97edfb2422598ea620e8219449fa9b
author Adam Lesinski <adamlesinski@google.com> Wed May 17 19:28:38 2017 -0700
committer Adam Lesinski <adamlesinski@google.com> Wed May 24 15:14:29 2017 -0700
tree 4e7c29d6b47c464dd5aa0af204d86a7340b0084f
parent 0418b72fd2c91f32c42e3a406df2a866888fc766

AAPT2: Implement attribute compat versioning

This change defines some hardcoded rules to degrade
attributes in newer SDKs to specific older attributes.

An attribute with a degrade rule will generate a new XML for the API
in which the attribute resulting from the degradation was introduced.

Since API 22 (Lollipop MR1), attributes are correctly ignored and do
not need to be versioned. In XML files defined for APIs 22+, the
original and degraded attributes coexist in the same XML file.

One such example is paddingHorizontal, introduced in API 26.
paddingHorizontal degrades to paddingLeft and paddingRight, which
were both introduced in API 1.

Bug: 35763493
Test: make aapt2_tests
Change-Id: I4aa8755a9ee2c0cc5afdc55c3d30093fd3a47f3d

tools/aapt2/process/SymbolTable.cpp

diff --git a/tools/aapt2/process/SymbolTable.cpp b/tools/aapt2/process/SymbolTable.cpp
index 1a648bf..882a85b 100644
--- a/tools/aapt2/process/SymbolTable.cpp
+++ b/tools/aapt2/process/SymbolTable.cpp
@@ -237,14 +237,12 @@
   }
 
   // We found a resource.
-  std::unique_ptr<SymbolTable::Symbol> s = util::make_unique<SymbolTable::Symbol>();
-  s->id = id;
+  std::unique_ptr<SymbolTable::Symbol> s = util::make_unique<SymbolTable::Symbol>(id);
 
   // Check to see if it is an attribute.
   for (size_t i = 0; i < (size_t)count; i++) {
     if (entry[i].map.name.ident == android::ResTable_map::ATTR_TYPE) {
-      s->attribute = std::make_shared<Attribute>(false);
-      s->attribute->type_mask = entry[i].map.value.data;
+      s->attribute = std::make_shared<Attribute>(false, entry[i].map.value.data);
       break;
     }
   }

tools/aapt2/process/SymbolTable.h

diff --git a/tools/aapt2/process/SymbolTable.h b/tools/aapt2/process/SymbolTable.h
index bd252d2..4a2181e 100644
--- a/tools/aapt2/process/SymbolTable.h
+++ b/tools/aapt2/process/SymbolTable.h
@@ -53,16 +53,12 @@
 class SymbolTable {
  public:
   struct Symbol {
-    Symbol() : Symbol(Maybe<ResourceId>{}) {}
+    Symbol() = default;
 
-    explicit Symbol(const Maybe<ResourceId>& i) : Symbol(i, nullptr) {}
-
-    Symbol(const Maybe<ResourceId>& i, const std::shared_ptr<Attribute>& attr)
-        : Symbol(i, attr, false) {}
-
-    Symbol(const Maybe<ResourceId>& i, const std::shared_ptr<Attribute>& attr,
-           bool pub)
-        : id(i), attribute(attr), is_public(pub) {}
+    explicit Symbol(const Maybe<ResourceId>& i, const std::shared_ptr<Attribute>& attr = {},
+                    bool pub = false)
+        : id(i), attribute(attr), is_public(pub) {
+    }
 
     Symbol(const Symbol&) = default;
     Symbol(Symbol&&) = default;