imag/lib/entry/libimagentryref/src/refstore.rs

292 lines
12 KiB
Rust

//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015, 2016 Matthias Beyer <mail@beyermatthias.de> and contributors
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; version
// 2.1 of the License.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
use std::path::PathBuf;
use std::collections::BTreeMap;
use std::fs::File;
use libimagstore::store::FileLockEntry;
use libimagstore::storeid::IntoStoreId;
use libimagstore::storeid::StoreId;
use libimagstore::storeid::StoreIdIterator;
use libimagstore::store::Store;
use toml::Value;
use error::RefErrorKind as REK;
use error::RefError as RE;
use error::ResultExt;
use error::Result;
use flags::RefFlags;
use hasher::*;
use module_path::ModuleEntryPath;
use util::*;
pub trait RefStore {
/// Check whether there is a reference to the file at `pb`
fn exists(&self, pb: PathBuf) -> Result<bool>;
/// Get a Ref object from the store by hash.
///
/// Returns None if the hash cannot be found.
fn get_by_hash<'a>(&'a self, hash: String) -> Result<Option<FileLockEntry<'a>>>;
/// Find a store id by partial ref (also see documentation for
/// `RefStore::get_by_partitial_hash()`.
fn find_storeid_by_partial_hash(&self, hash: &String) -> Result<Option<StoreId>>;
/// Get a Ref object from the store by (eventually partial) hash.
///
/// If the hash is complete, `RefStore::get_by_hash()` should be used as it is cheaper.
/// If the hash comes from user input and thus might be abbreviated, this function can be used.
fn get_by_partitial_hash<'a>(&'a self, hash: &String) -> Result<Option<FileLockEntry<'a>>>;
/// Delete a ref by hash
///
/// If the returned Result contains an error, the ref might not be deleted.
fn delete_by_hash(&self, hash: String) -> Result<()>;
/// Create a Ref object which refers to `pb`
fn create<'a>(&'a self, pb: PathBuf, flags: RefFlags) -> Result<FileLockEntry<'a>>;
fn create_with_hasher<'a, H: Hasher>(&'a self, pb: PathBuf, flags: RefFlags, h: H)
-> Result<FileLockEntry<'a>>;
/// Get all reference objects
fn all_references(&self) -> Result<StoreIdIterator>;
}
impl RefStore for Store {
/// Check whether there is a reference to the file at `pb`
fn exists(&self, pb: PathBuf) -> Result<bool> {
pb.canonicalize()
.chain_err(|| REK::PathCanonicalizationError)
.and_then(|c| hash_path(&c))
.chain_err(|| REK::PathHashingError)
.and_then(|hash| {
self.retrieve_for_module("ref").map(|iter| (hash, iter)).map_err(From::from)
})
.and_then(|(hash, possible_refs)| {
// This is kind of a manual Iterator::filter() call what we do here, but with the
// actual ::filter method we cannot return the error in a nice way, so we do it
// manually here. If you can come up with a better version of this, feel free to
// take this note as a todo.
for r in possible_refs {
let contains_hash = r.to_str()
.chain_err(|| REK::TypeConversionError)
.map(|s| s.contains(&hash[..]))
?;
if !contains_hash {
continue;
}
match self.get(r.clone())? {
Some(fle) => {
if read_reference(&fle).map(|path| path == pb).unwrap_or(false) {
return Ok(true)
}
},
None => {
let e = format!("Failed to get from store: {}", r);
return Err(e).map_err(From::from)
},
}
}
Ok(false)
})
}
/// Get a Ref object from the store by hash.
///
/// Returns None if the hash cannot be found.
fn get_by_hash<'a>(&'a self, hash: String) -> Result<Option<FileLockEntry<'a>>> {
ModuleEntryPath::new(hash)
.into_storeid()
.and_then(|id| self.get(id))
.map_err(From::from)
}
fn find_storeid_by_partial_hash(&self, hash: &String) -> Result<Option<StoreId>> {
debug!("Trying to find '{}' in store...", hash);
for id in self.retrieve_for_module("ref")? {
let components_have_hash = id
.components()
.any(|c| c.as_os_str().to_str().map(|s| s.contains(hash)).unwrap_or(false));
if components_have_hash {
debug!("Found hash '{}' in {:?}", hash, id);
return Ok(Some(id))
}
}
Ok(None)
}
/// Get a Ref object from the store by (eventually partial) hash.
///
/// If the hash is complete, `RefStore::get_by_hash()` should be used as it is cheaper.
/// If the hash comes from user input and thus might be abbreviated, this function can be used.
fn get_by_partitial_hash<'a>(&'a self, hash: &String) -> Result<Option<FileLockEntry<'a>>> {
match self.find_storeid_by_partial_hash(hash)? {
Some(id) => self.get(id).map_err(From::from),
None => Ok(None),
}
}
/// Delete a ref by hash
///
/// If the returned Result contains an error, the ref might not be deleted.
fn delete_by_hash(&self, hash: String) -> Result<()> {
ModuleEntryPath::new(hash)
.into_storeid()
.and_then(|id| self.delete(id))
.map_err(From::from)
}
/// Create a Ref object which refers to `pb`
fn create<'a>(&'a self, pb: PathBuf, flags: RefFlags) -> Result<FileLockEntry<'a>> {
self.create_with_hasher(pb, flags, DefaultHasher::new())
}
fn create_with_hasher<'a, H: Hasher>(&'a self, pb: PathBuf, flags: RefFlags, mut h: H)
-> Result<FileLockEntry<'a>>
{
use toml_query::insert::TomlValueInsertExt;
if !pb.exists() {
return Err(RE::from_kind(REK::RefTargetDoesNotExist));
}
if flags.get_content_hashing() && pb.is_dir() {
return Err(RE::from_kind(REK::RefTargetCannotBeHashed));
}
let (mut fle, content_hash, permissions, canonical_path) = { // scope to be able to fold
File::open(pb.clone())
.chain_err(|| REK::RefTargetFileCannotBeOpened)
// If we were able to open this file,
// we hash the contents of the file and return (file, hash)
.and_then(|mut file| {
let opt_contenthash = if flags.get_content_hashing() {
Some(h.create_hash(&pb, &mut file)?)
} else {
None
};
Ok((file, opt_contenthash))
})
// and then we get the permissions if we have to
// and return (file, content hash, permissions)
.and_then(|(file, opt_contenthash)| {
let opt_permissions = if flags.get_permission_tracking() {
Some(file.metadata()
.map(|md| md.permissions())
.chain_err(|| REK::RefTargetCannotReadPermissions)?)
} else {
None
};
Ok((opt_contenthash, opt_permissions))
})
// and then we try to canonicalize the PathBuf, because we want to store a
// canonicalized path
// and return (file, content hash, permissions, canonicalized path)
.and_then(|(opt_contenthash, opt_permissions)| {
pb.canonicalize()
.map(|can| (opt_contenthash, opt_permissions, can))
// if PathBuf::canonicalize() failed, build an error from the return value
.chain_err(|| REK::PathCanonicalizationError)
})
// and then we hash the canonicalized path
// and return (file, content hash, permissions, canonicalized path, path hash)
.and_then(|(opt_contenthash, opt_permissions, can)| {
let path_hash = hash_path(&can).chain_err(|| REK::PathHashingError)?;
Ok((opt_contenthash, opt_permissions, can, path_hash))
})
// and then we convert the PathBuf of the canonicalized path to a String to be able
// to save it in the Ref FileLockEntry obj
// and return
// (file, content hash, permissions, canonicalized path as String, path hash)
.and_then(|(opt_conhash, opt_perm, can, path_hash)| {
match can.to_str().map(String::from) {
// UTF convert error in PathBuf::to_str(),
None => Err(RE::from_kind(REK::PathUTF8Error)),
Some(can) => Ok((opt_conhash, opt_perm, can, path_hash))
}
})
// and then we create the FileLockEntry in the Store
// and return (filelockentry, content hash, permissions, canonicalized path)
.and_then(|(opt_conhash, opt_perm, can, path_hash)| {
let fle = self.create(ModuleEntryPath::new(path_hash))?;
Ok((fle, opt_conhash, opt_perm, can))
})?
};
for tpl in [
Some((String::from("ref"), Value::Table(BTreeMap::new()))),
Some((String::from("ref.permissions"), Value::Table(BTreeMap::new()))),
Some((String::from("ref.path"), Value::String(canonical_path))),
Some((String::from("ref.content_hash"), Value::Table(BTreeMap::new()))),
content_hash.map(|hash| {
(format!("ref.content_hash.{}", h.hash_name()), Value::String(hash))
}),
permissions.map(|p| {
(String::from("ref.permissions.ro"), Value::Boolean(p.readonly()))
}),
].into_iter()
{
match tpl {
&Some((ref s, ref v)) => {
match fle.get_header_mut().insert(s, v.clone()) {
Ok(Some(_)) => {
let e = RE::from_kind(REK::HeaderFieldAlreadyExistsError);
return Err(e).chain_err(|| REK::HeaderFieldWriteError);
},
Ok(None) => {
// Okay, we just inserted a new header value...
},
Err(e) => return Err(e).chain_err(|| REK::HeaderFieldWriteError),
}
}
&None => {
debug!("Not going to insert.");
}
}
}
Ok(fle)
}
fn all_references(&self) -> Result<StoreIdIterator> {
self.retrieve_for_module("ref").map_err(From::from)
}
}