added trait for interacting with persistent storage; tried to make Results easier

4 files changed, 121 insertions, 2 deletions

diff --git a/src/main.rs b/src/main.rs
index 92912c2..4301a07 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -27,6 +27,7 @@ mod savestate;
 mod defaultencyclopedia;
 mod playerstate;
 mod playerid;
+mod persistence;
 
 pub use self::pos::Pos;
 pub use self::playerid::PlayerId;
diff --git a/src/persistence.rs b/src/persistence.rs
new file mode 100644
index 0000000..fc04378
--- /dev/null
+++ b/src/persistence.rs
@@ -0,0 +1,77 @@
+
+use std::path::PathBuf;
+use std::fs;
+use serde_json;
+use serde_json::Value;
+use crate::{
+	PlayerId,
+	savestate::SaveState,
+	playerstate::PlayerState,
+	util::Result,
+	aerr
+};
+
+pub trait PersistentStorage {
+	
+	fn load_room(&self, name: String) -> Result<SaveState>;
+	
+	fn load_player(&self, id: PlayerId) -> Result<PlayerState>;
+	
+	fn save_room(&self, name: String, state: SaveState) -> Result<()>;
+	
+	fn save_player(&self, id: PlayerId, sate: PlayerState) -> Result<()>;
+	
+}
+
+
+pub struct FileStorage {
+	directory: PathBuf
+}
+
+impl PersistentStorage for FileStorage {
+	
+	fn load_room(&self, name: String) -> Result<SaveState> {
+		let mut path = self.directory.clone();
+		path.push("rooms");
+		let fname = name + ".save.json";
+		path.push(fname);
+		let text = fs::read_to_string(path)?;
+		let json: Value = serde_json::from_str(&text)?;
+		SaveState::from_json(&json).ok_or(aerr!("not a valid save state"))
+	}
+	
+	fn load_player(&self, id: PlayerId) -> Result<PlayerState> {
+		let mut path = self.directory.clone();
+		path.push("players");
+		let fname = id.name + ".save.json";
+		path.push(fname);
+		let text = fs::read_to_string(path)?;
+		let json: Value = serde_json::from_str(&text)?;
+		PlayerState::from_json(&json).ok_or(aerr!("not a valid save state"))
+	}
+	
+	fn save_room(&self, name: String, state: SaveState) -> Result<()> {
+		let mut path = self.directory.clone();
+		path.push("rooms");
+		fs::create_dir_all(&path)?;
+		let fname = name + ".save.json";
+		path.push(fname);
+		let text = state.to_json().to_string();
+		// todo: write to a temp file first
+		fs::write(path, text)?;
+		Ok(())
+	}
+	
+	fn save_player(&self, id: PlayerId, state: PlayerState) -> Result<()> {
+		let mut path = self.directory.clone();
+		path.push("players");
+		fs::create_dir_all(&path)?;
+		let fname = id.name + ".save.json";
+		path.push(fname);
+		let text = state.to_json().to_string();
+		// todo: write to a temp file first
+		fs::write(path, text)?;
+		Ok(())
+	}
+}
+
diff --git a/src/playerstate.rs b/src/playerstate.rs
index b9a7f1f..dac463b 100644
--- a/src/playerstate.rs
+++ b/src/playerstate.rs
@@ -43,7 +43,7 @@ impl PlayerState {
 		})
 	}
 
-	pub fn from_json(val: Value) -> Option<Self> {
+	pub fn from_json(val: &Value) -> Option<Self> {
 		let inventory = val.get("inventory")?;
 		let mut items = vec![];
 		for item in inventory.get("items")?.as_array()? {
diff --git a/src/util.rs b/src/util.rs
index 34d5670..1aee8a4 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,5 +1,6 @@
 
-
+use std::error::Error;
+use std::fmt::{Display, Formatter};
 use std::cmp::{min, max};
 use serde_json::Value;
 
@@ -12,6 +13,46 @@ pub trait ToJson {
 }
 
 
+pub type AnyError = Box<dyn Error + 'static>;
+pub type Result<T> = std::result::Result<T, AnyError>;
+
+#[derive(Debug)]
+pub struct AError {
+	text: String
+}
+
+impl AError {
+	pub fn new(txt: &str) -> Self{
+		AError {
+			text: txt.to_string()
+		}
+	}
+}
+
+impl Error for AError {
+	fn source(&self) -> Option<&(dyn Error + 'static)> {
+		None
+	}
+}
+
+impl Display for AError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Error: {}", self.text)
+    }
+}
+
+
+#[macro_export]
+macro_rules! aerr {
+	($description:expr) => {Box::new(crate::util::AError::new($description))}
+}
+
+#[macro_export]
+macro_rules! err {
+	($description:expr) => {Err(crate::aerr!($description))}
+}
+
+
 #[macro_export]
 macro_rules! hashmap {
 	( $($key:expr => $value:expr ),* ) => {{