extensive rewrite to use json for storage:

sqlite3 requires the directory where the database resides to be
writeable by the user. This presents a problem on multiuser UNIX systems
where they may want to limit areas where users have write access.

This rewrite totally scraps the sqlite3 database in favor of a pretty
simple json file consisting of an array of posts. flock(2) locking is
used to synchronize access to the file and make sure two clients aren't
trying to write to it at once. The locking is fairly granular right now,
but later I may change it to using a single lock for the duration of
execution since race conditions are *possible*, if unlikely for the
purposes of clinte's intended use.

1 files changed, 78 insertions, 43 deletions

diff --git a/src/db.rs b/src/db.rs
index 84f209b..90ff548 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -1,68 +1,94 @@
-use std::time;
+use fd_lock::FdLock;
+use serde::{Deserialize, Serialize};
+
+use std::fs;
+use std::fs::File;
 
 use crate::conf;
 use crate::error;
 
-const DB_PATH: &str = "/usr/local/clinte/clinte.db";
+#[cfg(test)]
+pub const PATH: &str = "clinte.json";
+
+#[cfg(not(test))]
+pub const PATH: &str = "/usr/local/clinte/clinte.json";
 
-#[derive(Debug)]
+#[derive(Debug, Deserialize, Serialize)]
 pub struct Post {
-    pub id: u32,
     pub title: String,
     pub author: String,
     pub body: String,
 }
 
+#[derive(Debug, Deserialize, Serialize)]
+pub struct Posts {
+    pub posts: Vec<Post>,
+}
+
 #[derive(Debug)]
 pub struct Conn {
-    pub conn: rusqlite::Connection,
+    pub conn: FdLock<std::fs::File>,
 }
 
 impl Conn {
-    pub fn init(path: &str) -> rusqlite::Connection {
-        let start = time::Instant::now();
-
+    pub fn init(path: &str) -> Self {
         if *conf::DEBUG {
-            log::info!("Connecting to database");
+            log::info!("Opening clinte.json");
         }
 
-        let conn = error::helper(
-            rusqlite::Connection::open_with_flags(
-                path,
-                rusqlite::OpenFlags::SQLITE_OPEN_FULL_MUTEX
-                    | rusqlite::OpenFlags::SQLITE_OPEN_CREATE
-                    | rusqlite::OpenFlags::SQLITE_OPEN_READ_WRITE,
-            ),
-            "Could not connect to DB",
-        );
+        let file = error::helper(File::open(path), "Couldn't open clinte.json");
 
-        error::helper(
-            conn.execute(
-                "CREATE TABLE IF NOT EXISTS posts (
-            id INTEGER PRIMARY KEY NOT NULL,
-            title TEXT NOT NULL,
-            author TEXT NOT NULL,
-            body TEXT NOT NULL
-        )",
-                rusqlite::NO_PARAMS,
-            ),
-            "Could not initialize DB",
-        );
+        Self {
+            conn: FdLock::new(file),
+        }
+    }
+}
 
+impl Posts {
+    pub fn get_all(path: &str) -> Self {
         if *conf::DEBUG {
-            log::info!(
-                "Database connection established in {}ms",
-                start.elapsed().as_millis()
-            );
+            log::info!("Retrieving posts...");
         }
 
-        conn
+        let mut db = Conn::init(path);
+        let _guard = error::helper(db.conn.try_lock(), "Couldn't acquire lock on clinte.json");
+        let strdata = error::helper(fs::read_to_string(PATH), "Couldn't read clinte.json");
+        let out: Self = error::helper(serde_json::from_str(&strdata), "Couldn't parse clinte.json");
+
+        out
     }
 
-    pub fn new() -> Self {
-        Conn {
-            conn: Conn::init(DB_PATH),
-        }
+    pub fn replace(&mut self, n: usize, post: Post) {
+        self.posts[n] = post;
+    }
+
+    pub fn get(&self, n: usize) -> &Post {
+        &self.posts[n]
+    }
+
+    pub fn append(&mut self, post: Post) {
+        self.posts.push(post);
+    }
+
+    pub fn delete(&mut self, n: usize) {
+        self.posts.remove(n);
+    }
+
+    pub fn write(&self) {
+        let strdata = error::helper(
+            serde_json::to_string_pretty(&self),
+            "Couldn't serialize posts",
+        );
+
+        let mut db_fd = Conn::init(PATH);
+        let _guard = error::helper(
+            db_fd.conn.try_lock(),
+            "Couldn't acquire lock on clinte.json",
+        );
+        error::helper(
+            fs::write(PATH, &strdata),
+            "Couldn't write data to clinte.json",
+        );
     }
 }
 
@@ -71,10 +97,19 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_new() {
-        let conn = Conn::init(":memory:");
-        let mut stmt = conn.prepare("SELECT * FROM POSTS").unwrap();
+    fn test_init() {
+        let mut conn = Conn::init(PATH);
+        conn.conn.try_lock().unwrap();
+    }
+
+    #[test]
+    fn retrieve_posts_and_examine() {
+        let all = Posts::get_all(PATH);
+        assert_eq!(all.posts.len(), 1);
 
-        stmt.query_map(rusqlite::NO_PARAMS, |_| Ok(())).unwrap();
+        let post = all.get(0);
+        assert_eq!(post.title, "Welcome to CLI NoTEs!");
+        assert_eq!(post.author, "clinte!");
+        assert_eq!(post.body, "Welcome to clinte! For usage, run 'clinte -h'");
     }
 }