From a88697c0eded20076ba2f2cba3845718e4f003e9 Mon Sep 17 00:00:00 2001
From: Chris Nuernberger <chris@techascent.com>
Date: Sat, 25 May 2019 15:14:40 -0600
Subject: [PATCH] Edited without gettting latest.

---
 README.md                             | 64 ++++++++++++++++++++++++++-
 java/libpython_clj/jna/JVMBridge.java |  5 ++-
 project.clj                           |  3 +-
 3 files changed, 67 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index ac2077a..3a09308 100644
--- a/README.md
+++ b/README.md
@@ -10,18 +10,78 @@ advantages over a [10,000 line C binding layer](https://github.com/ninia/jep/tre
 ...if it works.
 
 
+## Key Design Points
+
+
+### Code Organization
+
+
+There are 3 rough sections of code:
+1. A JNA layer which is a 1-1 mapping most of the C API with no changes and full
+   documentation.  The docstrings on the functions match the documentation if you lookup
+   the 3.7 API documentation.  Users must manually manage the GIL when using this API
+   layer.
+
+2. An API implementation layer which knows about things like interpreters and type
+   symbol tables.  Users must know how to manipulate the GIL and how the two garbage
+   collectors work with each other to add to this layer.
+
+3. A public API layer.  Details like managing the GIL or messing with garbage collection
+   in general not leak out to this layer.
+
+
+
+### Interpreters
+
+Interpreters are global objects.  After initialize!, there is a main interpreter which
+is used automatically from any thread.  Access to the interpreters relies on thread
+local variables and interpreter locking so you can do things like:
+
+```clojure
+(with-interpreter interpreter
+  some code)
+```
+
+This type of thing grabs the GIL if it hasn't already been claimed by the current thread
+and off you go.  When the code is finished, it saves the interpreter thread state back
+into a global atom and thus releases the GIL.  Interpreters have both shared and
+per-interpreter state named `:shared-state` and `:interpreter-state` respectively.
+Shared state would be the global type symbol table.  Interpreter state contains things
+like a map of objects to their per-interpreter python bridging class.
+
+
+### Garbage Collection
+
+The system uses the tech.resource library to attach a GC hook to appropriate java object
+that releases the associated python object if the java object goes out of scope.
+Bridges use a similar technique to unregister the bridge on destruction of their python
+counterpar.  There should be no need for manual addref/release calls in any user code.
+
+
+### Copying Vs. Mirroring
+
+
+Objects either in python or in java may be either copied or mirrored into the other
+ecosystem.  Mirroring allows sharing complex and potentially changing datastructures
+while copying allows a cleaner partitioning of concerns and frees both garbage
+collection systems to act more independently.  Numeric buffers that have a direct
+representation as a C-ptr (the datatype native-buffer type) have a zero-copy pathway
+via numpy.
+
+
+
 ## Resources
 
 * [libpython C api](https://docs.python.org/3.7/c-api/index.html#c-api-index)
 * [spacy-cpp](https://github.com/d99kris/spacy-cpp)
 * [base classes for python protocols](https://docs.python.org/3.7/library/collections.abc.html#collections-abstract-base-classes)
 
-## 
+##
 
 ## Usage
 
 ```console
-sudo apt install libpython3.7-dev
+sudo apt install libpython3.6-dev
 ```
 
 ```clojure
diff --git a/java/libpython_clj/jna/JVMBridge.java b/java/libpython_clj/jna/JVMBridge.java
index 30e16b5..5906057 100644
--- a/java/libpython_clj/jna/JVMBridge.java
+++ b/java/libpython_clj/jna/JVMBridge.java
@@ -4,11 +4,14 @@
 import com.sun.jna.*;
 
 
-public interface JVMBridge
+public interface JVMBridge extends AutoCloseable
 {
   public Pointer getAttr(String name);
   public void setAttr(String name, Pointer val);
   public String[] dir();
   public Object interpreter();
   public Object wrappedObject();
+  // Called from python when the python mirror is deleted.
+  // This had better not throw anything.
+  public default void close() {}
 }
diff --git a/project.clj b/project.clj
index ab906bf..d7438bf 100644
--- a/project.clj
+++ b/project.clj
@@ -5,7 +5,6 @@
             :url "https://www.eclipse.org/legal/epl-2.0/"}
   :dependencies [[org.clojure/clojure "1.10.1-beta2"]
                  [techascent/tech.datatype "4.0-alpha36"]
-                 [camel-snake-kebab "0.4.0"]
-                 [potemkin "0.4.4"]]
+                 [camel-snake-kebab "0.4.0"]]
   :repl-options {:init-ns clj-libpython.core}
   :java-source-paths ["java"])