Add this ability to install Extensions using preferences. Also known as: port the installation mechanism to other platforms.

We already have the ability to install extensions using a registry key. That works only on Windows so this new change adds the same but using preferences instead of the Registry. This will eventually allow us to pre-install certain extensions when we install Chrome.

BUG=12060
TEST=Covered by unit tests, but to test manually: close Chrome, open your Preferences file (in your profile) and add this (after substituting all <values> in elbow brackets):

   "extensions": {
      "settings": {
         "<your_extension_id_lowercased>": {
            "external_crx": "<path_to_crx>",
            "external_version": "<crx version>"
         }
      },
   },

... then start Chrome. Your extension should get installed. 
Review URL: http://codereview.chromium.org/119195

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17777 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 71 insertions, 22 deletions

diff --git a/chrome/common/extensions/extension.cc b/chrome/common/extensions/extension.cc
index f6a579b..c641afc 100644
--- a/chrome/common/extensions/extension.cc
+++ b/chrome/common/extensions/extension.cc
@@ -15,6 +15,10 @@
 #include "chrome/common/extensions/user_script.h"
 #include "chrome/common/url_constants.h"
 
+#if defined(OS_WIN)
+#include "base/registry.h"
+#endif
+
 const char Extension::kManifestFilename[] = "manifest.json";
 
 const wchar_t* Extension::kContentScriptsKey = L"content_scripts";
@@ -142,6 +146,11 @@ const char* Extension::kInvalidThemeTintsError =
 const char* Extension::kThemesCannotContainExtensionsError =
     "A theme cannot contain extensions code.";
 
+#if defined(OS_WIN)
+const char* Extension::kExtensionRegistryPath =
+    "Software\\Google\\Chrome\\Extensions";
+#endif
+
 const size_t Extension::kIdSize = 20;  // SHA1 (160 bits) == 20 bytes
 
 Extension::~Extension() {
@@ -155,6 +164,24 @@ const std::string Extension::VersionString() const {
 }
 
 // static
+bool Extension::IdIsValid(const std::string& id) {
+  // Verify that the id is legal.  The id is a hex string of the SHA-1 hash of
+  // the public key.
+  std::vector<uint8> id_bytes;
+  if (!HexStringToBytes(id, &id_bytes) || id_bytes.size() != kIdSize)
+    return false;
+
+  // We only support lowercase IDs, because IDs can be used as URL components
+  // (where GURL will lowercase it).
+  std::string temp = id;
+  StringToLowerASCII(temp);
+  if (temp != id)
+    return false;
+
+  return true;
+}
+
+// static
 GURL Extension::GetResourceURL(const GURL& extension_url,
                                const std::string& relative_path) {
   DCHECK(extension_url.SchemeIs(chrome::kExtensionScheme));
@@ -174,6 +201,19 @@ const PageAction* Extension::GetPageAction(std::string id) const {
   return it->second;
 }
 
+Extension::Location Extension::ExternalExtensionInstallType(
+    std::string registry_path) {
+#if defined(OS_WIN)
+  HKEY reg_root = HKEY_LOCAL_MACHINE;
+  RegKey key;
+  registry_path.append("\\");
+  registry_path.append(id_);
+  if (key.Open(reg_root, ASCIIToWide(registry_path).c_str()))
+    return Extension::EXTERNAL_REGISTRY;
+#endif
+  return Extension::EXTERNAL_PREF;
+}
+
 // Helper method that loads a UserScript object from a dictionary in the
 // content_script list of the manifest.
 bool Extension::LoadUserScriptHelper(const DictionaryValue* content_script,
@@ -449,10 +489,8 @@ bool Extension::InitFromValue(const DictionaryValue& source, bool require_id,
     // (where GURL will lowercase it).
     StringToLowerASCII(&id_);
 
-    // Verify that the id is legal.  The id is a hex string of the SHA-1 hash of
-    // the public key.
-    std::vector<uint8> id_bytes;
-    if (!HexStringToBytes(id_, &id_bytes) || id_bytes.size() != kIdSize) {
+    // Verify that the id is legal.
+    if (!IdIsValid(id_)) {
       *error = kInvalidIdError;
       return false;
     }
diff --git a/chrome/common/extensions/extension.h b/chrome/common/extensions/extension.h
index 76f4b20..9b79f30 100644
--- a/chrome/common/extensions/extension.h
+++ b/chrome/common/extensions/extension.h
@@ -24,10 +24,17 @@ class Extension {
   // What an extension was loaded from.
   enum Location {
     INVALID,
-    INTERNAL,  // A crx file from the internal Extensions directory.
-    EXTERNAL,  // A crx file from an external directory (via eg the registry
-               // on Windows).
-    LOAD  // --load-extension.
+    INTERNAL,           // A crx file from the internal Extensions directory.
+    EXTERNAL_PREF,      // A crx file from an external directory (via prefs).
+    EXTERNAL_REGISTRY,  // A crx file from an external directory (via eg the
+                        // registry on Windows).
+    LOAD                // --load-extension.
+  };
+
+  enum State {
+    DISABLED,
+    ENABLED,
+    KILLBIT,  // Don't install/upgrade (applies to external extensions only).
   };
 
   // An NPAPI plugin included in the extension.
@@ -114,6 +121,10 @@ class Extension {
   static const char* kThemesCannotContainExtensionsError;
   static const char* kMissingFileError;
 
+#if defined(OS_WIN)
+  static const char* kExtensionRegistryPath;
+#endif
+
   // The number of bytes in a legal id.
   static const size_t kIdSize;
 
@@ -121,6 +132,15 @@ class Extension {
   explicit Extension(const FilePath& path);
   virtual ~Extension();
 
+  // Checks to see if the extension has a valid ID.
+  static bool IdIsValid(const std::string& id);
+
+  // Whether the |location| is external or not.
+  static inline bool IsExternalLocation(Location location) {
+    return location == Extension::EXTERNAL_PREF ||
+           location == Extension::EXTERNAL_REGISTRY;
+  }
+
   // Returns an absolute url to a resource inside of an extension. The
   // |extension_url| argument should be the url() from an Extension object. The
   // |relative_path| can be untrusted user input. The returned URL will either
@@ -169,7 +189,11 @@ class Extension {
   // Retrieves a page action by |id|.
   const PageAction* GetPageAction(std::string id) const;
 
-  // Theme-related
+  // Returns the origin of this extension. This function takes a |registry_path|
+  // so that the registry location can be overwritten during testing.
+  Location ExternalExtensionInstallType(std::string registry_path);
+
+  // Theme-related.
   DictionaryValue* GetThemeImages() const { return theme_images_.get(); }
   DictionaryValue* GetThemeColors() const { return theme_colors_.get(); }
   DictionaryValue* GetThemeTints() const { return theme_tints_.get(); }
diff --git a/chrome/common/extensions/extension_unpacker.cc b/chrome/common/extensions/extension_unpacker.cc
index f98e875..916b048 100644
--- a/chrome/common/extensions/extension_unpacker.cc
+++ b/chrome/common/extensions/extension_unpacker.cc
@@ -41,19 +41,6 @@ struct ExtensionHeader {
 const size_t kZipHashBytes = 32;  // SHA-256
 const size_t kZipHashHexBytes = kZipHashBytes * 2;  // Hex string is 2x size.
 
-#if defined(OS_WIN)
-
-// Registry key where registry defined extension installers live.
-const wchar_t kRegistryExtensions[] = L"Software\\Google\\Chrome\\Extensions";
-
-// Registry value of of that key that defines the path to the .crx file.
-const wchar_t kRegistryExtensionPath[] = L"path";
-
-// Registry value of that key that defines the current version of the .crx file.
-const wchar_t kRegistryExtensionVersion[] = L"version";
-
-#endif
-
 // A marker file to indicate that an extension was installed from an external
 // source.
 const char kExternalInstallFile[] = "EXTERNAL_INSTALL";