mash: Serialize ShelfIDs for property conversion and transport.

ash/public/cpp/shelf_types.cc

Index: ash/public/cpp/shelf_types.cc
diff --git a/ash/public/cpp/shelf_types.cc b/ash/public/cpp/shelf_types.cc
index 53d683239caf45fcfd8a4f7b5dce63ff02048523..983bdf09bd1d895cfa5e00bc25494309cc133699 100644
--- a/ash/public/cpp/shelf_types.cc
+++ b/ash/public/cpp/shelf_types.cc
@@ -5,9 +5,17 @@
 #include "ash/public/cpp/shelf_types.h"
 
 #include "base/logging.h"
+#include "base/strings/string_split.h"
 
 namespace ash {
 
+namespace {
+
+// A delimiter used to serialize the ShelfID string pair as a single string.
+constexpr char kDelimiter[] = {'|', 0};

[James Cook, 2017/05/15 16:37:23]

const char kDelimiter[] = "|"; doesn't work here? Why the {} initializer?

[msw, 2017/05/15 19:21:31]

Done.

+
+}  // namespace
+
 bool IsValidShelfItemType(int64_t type) {
   return type == TYPE_APP_PANEL || type == TYPE_PINNED_APP ||
          type == TYPE_APP_LIST || type == TYPE_BROWSER_SHORTCUT ||
@@ -44,4 +52,20 @@ bool ShelfID::IsNull() const {
   return app_id.empty() && launch_id.empty();
 }
 
+std::string ShelfID::Serialize() const {
+  DCHECK_EQ(std::string::npos, app_id.find(kDelimiter)) << "Invalid ShelfID";
+  DCHECK_EQ(std::string::npos, launch_id.find(kDelimiter)) << "Invalid ShelfID";
+  return app_id + std::string(kDelimiter) + launch_id;

[James Cook, 2017/05/15 16:37:23]

You might be able to skip the std::string(kDelimiter) here, which might end up
using a slightly-more-efficient template-specialized char* append for
std::string. Not sure, tho, have to see if it compiles.

[msw, 2017/05/15 19:21:31]

Done.

+}
+
+// static
+ShelfID ShelfID::Deserialize(const std::string* string) {
+  if (!string)

[James Cook, 2017/05/15 16:37:23]

Could this be a DCHECK?

[msw, 2017/05/15 19:21:31]

I'd rather not, every kShelfIDKey property read would need special casing for
null values.

+    return ShelfID();
+  std::vector<std::string> components = base::SplitString(
+      *string, kDelimiter, base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
+  DCHECK_EQ(2u, components.size()) << "ShelfID serialized incorrectly.";
+  return ShelfID(components[0], components[1]);
+}
+
 }  // namespace ash