From ae321a99235d8a9a4dbd317f4178c294b1128998 Mon Sep 17 00:00:00 2001
From: able <abl3theabove@gmail.com>
Date: Mon, 10 Jul 2023 22:54:05 -0500
Subject: [PATCH] CAPS: Adding in capabilities

---
 kernel/src/capabilities.rs | 177 +++++++++++++++++++++++++++++++++++++
 kernel/src/handle.rs       |   1 +
 kernel/src/lib.rs          |   1 +
 3 files changed, 179 insertions(+)
 create mode 100644 kernel/src/capabilities.rs

diff --git a/kernel/src/capabilities.rs b/kernel/src/capabilities.rs
new file mode 100644
index 000000000..ed95595d9
--- /dev/null
+++ b/kernel/src/capabilities.rs
@@ -0,0 +1,177 @@
+//! AbleOS capability tree implementation
+
+use {
+    alloc::{
+        format,
+        string::{String, ToString},
+        vec,
+    },
+    core::fmt,
+};
+
+// Seperate
+use alloc::vec::Vec;
+
+struct Argument {
+    name:  String,
+    type_: String,
+}
+
+struct Function {
+    name: String,
+    args: Vec<Argument>,
+    ret:  Option<String>,
+}
+
+struct Capability {
+    name: String,
+    functions: Vec<Function>,
+    sub_capabilities: Vec<Capability>,
+}
+
+impl Capability {
+    fn new(name: String) -> Capability {
+        Capability {
+            name,
+            functions: Vec::new(),
+            sub_capabilities: Vec::new(),
+        }
+    }
+}
+
+impl fmt::Display for Capability {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Capability: {}\n", self.name)?;
+        for function in &self.functions {
+            write!(f, "  Function: {}\n", function.name)?;
+            for arg in &function.args {
+                write!(f, "    Argument: {} (Type: {})\n", arg.name, arg.type_)?;
+            }
+            if let Some(ret_type) = &function.ret {
+                write!(f, "    Return Type: {}\n", ret_type)?;
+            } else {
+                write!(f, "    Return Type: None\n")?;
+            }
+        }
+        for sub_capability in &self.sub_capabilities {
+            write!(f, "{}", sub_capability.to_string_with_indentation(2))?;
+        }
+        Ok(())
+    }
+}
+
+impl Capability {
+    fn to_string_with_indentation(&self, level: usize) -> String {
+        let indent = "  ".repeat(level);
+        let mut result = format!("{}Capability: {}\n", indent, self.name);
+        for function in &self.functions {
+            result.push_str(&format!("{}  Function: {}\n", indent, function.name));
+            for arg in &function.args {
+                result.push_str(&format!(
+                    "{}    Argument: {} (Type: {})\n",
+                    indent, arg.name, arg.type_
+                ));
+            }
+            if let Some(ret_type) = &function.ret {
+                result.push_str(&format!("{}    Return Type: {}\n", indent, ret_type));
+            } else {
+                result.push_str(&format!("{}    Return Type: None\n", indent));
+            }
+        }
+        for sub_capability in &self.sub_capabilities {
+            result.push_str(&sub_capability.to_string_with_indentation(level + 1));
+        }
+        result
+    }
+}
+
+struct CapabilityTree {
+    capabilities: Vec<Capability>,
+}
+
+impl CapabilityTree {
+    fn new() -> CapabilityTree {
+        CapabilityTree {
+            capabilities: Vec::new(),
+        }
+    }
+}
+
+fn example() {
+    let mut capability_tree = Capability::new("VFS".to_string());
+
+    let mut file_management_capability = Capability::new("File Management".to_string());
+    file_management_capability.functions.push(Function {
+        name: "OpenFile".to_string(),
+        args: vec![
+            Argument {
+                name:  "path".to_string(),
+                type_: "String".to_string(),
+            },
+            Argument {
+                name:  "mode".to_string(),
+                type_: "String".to_string(),
+            },
+        ],
+        ret:  Some("FileHandle".to_string()),
+    });
+    file_management_capability.functions.push(Function {
+        name: "ReadFile".to_string(),
+        args: vec![
+            Argument {
+                name:  "file".to_string(),
+                type_: "FileHandle".to_string(),
+            },
+            Argument {
+                name:  "buffer".to_string(),
+                type_: "&mut [u8]".to_string(),
+            },
+            Argument {
+                name:  "length".to_string(),
+                type_: "usize".to_string(),
+            },
+        ],
+        ret:  Some("usize".to_string()),
+    });
+    file_management_capability.functions.push(Function {
+        name: "WriteFile".to_string(),
+        args: vec![
+            Argument {
+                name:  "file".to_string(),
+                type_: "FileHandle".to_string(),
+            },
+            Argument {
+                name:  "buffer".to_string(),
+                type_: "&[u8]".to_string(),
+            },
+        ],
+        ret:  None,
+    });
+
+    let mut directory_management_capability = Capability::new("Directory Management".to_string());
+    directory_management_capability.functions.push(Function {
+        name: "CreateDirectory".to_string(),
+        args: vec![Argument {
+            name:  "path".to_string(),
+            type_: "String".to_string(),
+        }],
+        ret:  Some("bool".to_string()),
+    });
+    directory_management_capability.functions.push(Function {
+        name: "ListDirectory".to_string(),
+        args: vec![Argument {
+            name:  "path".to_string(),
+            type_: "String".to_string(),
+        }],
+        ret:  Some("Vec<String>".to_string()),
+    });
+
+    capability_tree
+        .sub_capabilities
+        .push(file_management_capability);
+    capability_tree
+        .sub_capabilities
+        .push(directory_management_capability);
+
+    log::debug!("{}", capability_tree);
+}
diff --git a/kernel/src/handle.rs b/kernel/src/handle.rs
index 9cb34c87e..cc76284da 100644
--- a/kernel/src/handle.rs
+++ b/kernel/src/handle.rs
@@ -26,6 +26,7 @@ impl OSHandle {
 #[derive(Debug, Eq, Hash, PartialEq, Clone, Copy)]
 pub struct Handle {
     id:    OSHandle,
+    // TODO: Update this to be indexes into the caps
     perms: Permissions,
 }
 
diff --git a/kernel/src/lib.rs b/kernel/src/lib.rs
index 4aeb67c93..570bb5bdc 100644
--- a/kernel/src/lib.rs
+++ b/kernel/src/lib.rs
@@ -22,6 +22,7 @@ extern crate alloc;
 mod allocator;
 mod arch;
 mod bootmodules;
+pub mod capabilities;
 pub mod device_tree;
 pub mod handle;
 pub mod host;