Handle dependencies re static linking. GH #279

Previously we were hanging on the type destructors to pull in
the relevant objects. However that fails in many simple cases
where the object is never deleted.

For every type involved in the algo registry add static create
and providers functions to access the algo registry. Modify
lookup.h to be inline and call those functions, and move
a few to sub-headers (eg, get_pbkdf going to pbkdf.h). So
accessing the registry involves going through the same file
that handles the initialization, so there is no way to end up
with missing objs.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/lib/block/block_cipher.h b/src/lib/block/block_cipher.h
index 3f017dc89..cea07ac2d 100644
--- a/src/lib/block/block_cipher.h
+++ b/src/lib/block/block_cipher.h
@@ -22,6 +22,19 @@ class BOTAN_DLL BlockCipher : public SymmetricAlgorithm
       typedef SCAN_Name Spec;
 
       /**
+      * Create an instance based on a name
+      * Will return a null pointer if the algo/provider combination cannot
+      * be found. If providers is empty then best available is chosen.
+      */
+      static std::unique_ptr<BlockCipher> create(const std::string& algo_spec,
+                                                 const std::string& provider = "");
+
+      /**
+      * Returns the list of available providers for this algorithm, empty if not available
+      */
+      static std::vector<std::string> providers(const std::string& algo_spec);
+
+      /**
       * @return block size of this algorithm
       */
       virtual size_t block_size() const = 0;