Feature/rust sdk

docs/sdk/_category_.json

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+{
+  "label": "SDK",
+  "position": 8
+}

docs/sdk/future-work.md

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+---
+sidebar_position: 5
+---
+
+# Future work
+
+Currently, only a **Rust** SDK has been produced and can be used within the Holium protocol.
+
+The statically typed languages that we look forward to the most after it are **AssemblyScript** and 
+**Golang**.
+
+As for dynamically typed languages, **Python** and **Javascript** are deemed interesting because of the 
+many applications that they currently cover and the numerous libraries developed with them.
+
+As for how the Rust SDK API behaves, it currently ingest data as whole without any optimization. Ideally,
+that behavior would be changed so that data are dynamically fetched during the execution of a transformation.
+
+If those tasks interest you or if you have any query about them please feel free to reach us on any of 
+our contact channel.

docs/sdk/glossary.md

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+e---
+sidebar_position: 2
+---
+
+# Glossary
+
+We are on a **host** running **guest** Wasm bytecode on a given **runtime**.
+
+Compiled Wasm bytecode is called a **module**.
+
+In each **module** we can find between one or multiple **transformation wrapper(s)**. A **transformation wrapper**
+is the equivalent of a developed **pure transformation** (a function).
+
+When instantiating a **module** in a runtime, access points to **transformation wrapper**
+are called **entry points**.

docs/sdk/rationale.md

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+---
+sidebar_position: 1
+---
+
+# Rationale
+
+The transformations ran in the Holium protocol are Wasm based, meaning that code developed to run on the CLI
+has to be compiled to Wasm bytecode.
+
+As we aim for a global approach with our protocol we try to encompass as many languages as possible, allowing
+for many codebase to be usable. In that regard, one SDK should be developed per language that we wish
+to be usable in the Holium protocol. 
+
+The role of an Holium SDK is to adapt a codebase to run within the Holium protocol by following the 
+[specifications](./specifications.md). 
+
+At first the focus is most likely to be pointed on languages that currently support direct compilation 
+to Wasm (mostly statically typed languages). About dynamically typed languages some research are currently
+underway to study how they could be integrated as a base for transformation.
+
+
+

docs/sdk/rust-sdk/_category_.json

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+{
+  "label": "Rust SDK",
+  "position": 4
+}

docs/sdk/rust-sdk/constraints.md

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+---
+sidebar_position: 3
+---
+
+# Limitations
+
+<!-- TODO can be fixed, to see related ticket -->
+Some common Rust types are not implemented yet:
+- Enum
+- Tuples
+- Mutex
+- Result
+
+Also, functions or structures with lifetimes are not handled.

docs/sdk/rust-sdk/install.md

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+---
+sidebar_position: 1
+---
+
+# Install
+
+The Rust SDK is the Rust implementation of the [SDK specifications](../specifications.md).
+
+It leverages [procedural macros](https://doc.rust-lang.org/reference/procedural-macros.html) to be embedded
+as seamlessly as possible in a codebase.
+
+_Rust target_
+
+- Add rust compilation target for `wasm32-unknown-unknown`.
+
+_Cargo file_
+
+- Configure Cargo.toml with `crate-type = ["cdylib"]`
+- Add `holium-rs-sdk` as a dependency.
+

docs/sdk/rust-sdk/usage.md

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+---
+sidebar_position: 2
+---
+
+# Usage
+
+## Build a module
+
+- Use the `#[holium_bindgen]` procedural macro on every public functions and structures that should be exported.
+- Compile using `cargo build --target wasm32-unkown-unknwon --release`
+- Wasm bytecode can be found in `<crate_root>/target/wasm32-unkown-unknwon/release/<crate_name>.wasm`
+
+## How does it work
+
+- Adds `Serialize` & `Deserialize` derive code for exported structure
+- Implements `GenerateNode` trait to all exported structures
+- Generates wrapper function around exported function that will handle input payload and output payload
+
+In execution :
+- Receive data node as CBOR serialized from the host
+- Deserialize data node and fuse it with key node to generate input payload
+- Run client function with corresponding arguments
+- Convert return value to data node
+- Serialize data node as CBOR and send it to the host
+

docs/sdk/specifications.md

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+---
+sidebar_position: 3
+---
+
+# Specifications
+
+**Entry points** have the same name as the exported **pure transformation** they lead to.
+
+When passing data from the **host** to the **guest**, Wasm is currently limited. To bypass that limit we 
+directly interact with the guest's **linear memory**. By using pointers and lengths we are able
+to read and write complex data from and to our **module**.
+
+Here is an overview of a given execution:
+
+```plantuml 
+skinparam maxMessageSize 200
+
+database    "Data Repository"   as DR
+actor       "Holium Client"     as HC
+participant "**Transformations Wrapper**\nbuilt during compilation\nwith the procedural macro,\npart of the WASM module,\nexecuted in a WASM runtime" as Wrapper
+participant "**Pure Transformation**,\nother part of the WASM module,\nexecuted in a WASM runtime" as Transformation
+
+group Recursively fetching fragments of Holium data\nfrom a repository like IPFS
+DR -> HC: Fetch ""DAG-CBOR"" fragment #1.
+DR -> HC: Fetch ""DAG-CBOR"" fragment #2.
+DR -> HC: …
+DR -> HC: Fetch ""DAG-CBOR"" fragment #N.
+end
+
+group Defragmenting Holium data
+HC -> HC: Create a valid ""HoliumCBOR"" object.
+end
+
+group Executing the transformation
+
+HC -> Wrapper: Request execution of a transformation, providing its identifier and input ""HoliumCBOR"" parameter.
+
+alt input parameter of right type
+
+Wrapper -> Wrapper: Deserialize the ""HoliumCBOR"" input parameter into ""Rust-type"" input parameters expected by the pure transformation.
+Wrapper -> Transformation: A switch selects the right method and hands it over the ""Rust-type"" input parameters for execution..
+
+alt successful execution
+Transformation -> Transformation: Execute the pure transformation.
+Transformation -> Wrapper: Return success code together with ""Rust-type"" output parameters.
+Wrapper -> Wrapper: Serialize ""Rust-type"" output parameters into a ""HoliumCBOR"" object.
+Wrapper -> HC: Return success code and the result of the execution as a ""HoliumCBOR"" object.
+HC -> HC: Fragment ""HoliumCBOR"" object into ""DAG-CBOR"" storable fragments.
+HC -> DR: Push all new ""DAG-CBOR"" fragments to the repository.
+else failing execution
+Transformation ->x Transformation: Fail executing the transformation.
+Transformation -> Wrapper: Return failure code together with an error object.
+Wrapper -> : Return failure code and the error object.
+end
+
+else input parameter of wrong type
+
+Wrapper -> Wrapper: Fail deserializing the ""HoliumCBOR"" input parameter into ""Rust-type"" objects expected by the pure transformation.
+Wrapper -> HC: Return failure code together with an error object.
+
+end
+
+end
+``` 
+
+All **wrapped transformations** must have the same signature:
+
+`fn (ret_ptr: u32, input_ptr: u32, input_len: u32) -> ()`
+
+All pointers and lengths refer to pointers and lengths of data on the **linear memory** of our **guest**.
+
+`ret_ptr` contains data in a tuple of format `(u32, u32)` being the pointer and length of HoliumCBOR 
+return payload.
+
+`input_ptr` and `input_len` are the pointer and length of the input payload in HoliumCBOR format that
+should be used to run the transformation.

docusaurus.config.js

@@ -1,3 +1,5 @@
+const simplePlantUML = require("@akebifiky/remark-simple-plantuml");
+
 const lightCodeTheme = require('prism-react-renderer/themes/github');
 const darkCodeTheme = require('prism-react-renderer/themes/dracula');
 
@@ -93,6 +95,7 @@ module.exports = {
           // Please change this to your repo.
           editUrl:
             'https://github.com/facebook/docusaurus/edit/master/website/',
+          remarkPlugins: [simplePlantUML],
         },
         blog: {
           showReadingTime: true,

package.json

@@ -14,6 +14,7 @@
     "write-heading-ids": "docusaurus write-heading-ids"
   },
   "dependencies": {
+    "@akebifiky/remark-simple-plantuml": "^1.0.2",
     "@docusaurus/core": "2.0.0-beta.3",
     "@docusaurus/preset-classic": "2.0.0-beta.3",
     "@mdx-js/react": "^1.6.21",
@@ -37,4 +38,4 @@
       "last 1 safari version"
     ]
   }
-}
+}