WIP

libbsv/src/simple_db/db.rs

@@ -0,0 +1,145 @@
+// This file is part of bsv.
+//
+// bsv is free software: you can redistribute it and/or modify it under the
+// terms of the GNU Affero General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// cdb is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for
+// more details.
+//
+// You should have received a copy of the Affero GNU General Public License
+// along with cdb.  If not, see <https://www.gnu.org/licenses/>.
+
+
+extern crate tempfile;
+
+use std::path::{Path, PathBuf};
+use std::io::{Read, Seek};
+use std::fs::{File, OpenOptions, create_dir, create_dir_all};
+
+use tempfile::{NamedTempFile};
+
+use crate::core::error::*;
+use crate::core::ObjectId;
+use crate::core::{ObjectType, OTYPE_BLOB};
+
+use super::object::{
+    ObjectReader, WriteAsObject,
+};
+
+
+const OBJECTS_DIR: &str = "objects";
+const TMP_DIR: &str = "tmp";
+
+
+#[derive(Debug)]
+pub struct SimpleDb {
+    path: PathBuf,
+}
+
+
+impl SimpleDb {
+    pub fn new(path: &Path) -> Result<SimpleDb> {
+        Ok(SimpleDb {
+            path: path.into(),
+        })
+    }
+
+
+    pub fn setup(&self) -> Result<()> {
+        create_dir(self.objects_dir())?;
+        create_dir(self.tmp_dir())?;
+
+        Ok(())
+    }
+
+
+    pub fn has_object(&self, oid: &ObjectId) -> bool {
+        let obj_path = self.path_from_id(oid);
+        if let Ok(metadata) = std::fs::metadata(obj_path) {
+            metadata.is_file()
+        }
+        else {
+            false
+        }
+    }
+
+    pub fn store_object<R: Read + Seek>(&self, otype: &ObjectType, mut reader: R)
+        -> Result<ObjectId> {
+        let mut tmp_file = self.create_tmp_file()?;
+        let oid = reader.write_as_object(&mut tmp_file, otype)?;
+        let dst_file_path = self.path_from_id(&oid);
+
+        // TODO: Check if dst_file_path exists
+
+        create_dir_all(dst_file_path.parent().unwrap())?;
+        match tmp_file.persist(dst_file_path) {
+            Ok(file) => {
+                file.sync_data()?;
+                Ok(oid)
+            },
+            Err(err) => Err(err.error.into()),
+        }
+    }
+
+    pub fn store_file_as_blob(&self, file_path: &Path) -> Result<ObjectId> {
+        let file = OpenOptions::new().read(true).open(file_path)?;
+        self.store_object(OTYPE_BLOB, file)
+    }
+
+    pub fn read_object(&self, oid: &ObjectId) -> Result<ObjectReader<File>> {
+        let path = self.path_from_id(oid);
+        let file = OpenOptions::new().read(true).open(path)?;
+        ObjectReader::new(file)
+    }
+
+    fn objects_dir(&self) -> PathBuf {
+        let mut path = self.path.clone();
+        path.push(OBJECTS_DIR);
+        path
+    }
+
+    fn tmp_dir(&self) -> PathBuf {
+        let mut path = self.path.clone();
+        path.push(TMP_DIR);
+        path
+    }
+
+    fn path_from_id(&self, oid: &ObjectId) -> PathBuf {
+        let oid_str = oid.to_string();
+        let mut path = self.path.clone();
+
+        path.push(OBJECTS_DIR);
+        path.push(oid_str.get(..4).unwrap()); // unwrap is ok here because we know oid_str is a
+        path.push(oid_str.get(4..).unwrap()); // hexadecimal number (i.e. ascii only).
+
+        path
+    }
+
+    fn create_tmp_file(&self) -> Result<NamedTempFile> {
+        let tmp_dir = self.tmp_dir();
+
+        Ok(tempfile::Builder::new().tempfile_in(tmp_dir)?)
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    use std::str::{FromStr};
+
+    use super::ObjectId;
+    use super::SimpleDb;
+
+    #[test]
+    fn simple_db_path_from_id() {
+        let db = SimpleDb::new(std::path::Path::new(".bsv")).unwrap();
+        let oid = ObjectId::from_str("0001020304050607").unwrap();
+
+        let path = db.path_from_id(&oid);
+        assert_eq!(path, std::path::PathBuf::from(".bsv/objects/0001/020304050607"));
+    }
+}