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Rewrite external linking

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This commit is contained in:
Matthias Beyer 2016-04-08 23:35:04 +02:00
parent 17610efd74
commit 5645edeeff
2 changed files with 112 additions and 107 deletions
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4
libimaglink/src/error.rs
View file

@ -12,6 +12,7 @@ pub enum LinkErrorKind {
LinkTargetDoesNotExist,
InternalConversionError,
InvalidUri,
StoreReadError,
}
fn link_error_type_as_str(e: &LinkErrorKind) -> &'static str {
@ -33,6 +34,9 @@ fn link_error_type_as_str(e: &LinkErrorKind) -> &'static str {
&LinkErrorKind::InvalidUri
=> "URI is not valid",
&LinkErrorKind::StoreReadError
=> "Store read error",
}
}

215
libimaglink/src/external.rs
View file

@ -1,140 +1,141 @@
/// External linking is a complex implementation to be able to serve a clean and easy-to-use
/// interface.
///
/// Internally, there are no such things as "external links" (plural). Each Entry in the store can
/// only have _one_ external link.
///
/// This library does the following therefor: It allows you to have several external links with one
/// entry, which are internally one file in the store for each link, linked with "internal
/// linking".
///
/// This helps us greatly with deduplication of URLs.
///
use std::convert::Into;
use std::ops::Deref;
use libimagstore::store::Entry;
use libimagstore::store::EntryHeader;
use libimagstore::store::FileLockEntry;
use libimagstore::store::Store;
use libimagstore::storeid::StoreId;
use error::{LinkError, LinkErrorKind};
use error::LinkError as LE;
use error::LinkErrorKind as LEK;
use result::Result;
use internal::InternalLinker;
use toml::Value;
use toml::Table;
use url::Url;
#[derive(PartialOrd, Ord, Eq, PartialEq, Clone, Debug)]
pub struct Link {
link: String
/// "Link" Type, just an abstraction over FileLockEntry to have some convenience internally.
struct Link<'a> {
link: FileLockEntry<'a>
}
impl Link {
impl<'a> Link<'a> {
pub fn new(s: String) -> Link {
Link { link: s }
pub fn new(fle: FileLockEntry<'a>) -> Link<'a> {
Link { link: fle }
}
pub fn is_valid(&self) -> bool {
Url::parse(&self.link[..]).is_ok()
/// For interal use only. Load an Link from a store id, if this is actually a Link
fn retrieve(store: &'a Store, id: StoreId) -> Result<Option<Link<'a>>> {
store.retrieve(id)
.map(|fle| {
if let Some(_) = Link::get_link_uri_from_filelockentry(&fle) {
Some(Link {
link: fle
})
} else {
None
}
})
.map_err(|e| LE::new(LEK::StoreReadError, Some(Box::new(e))))
}
/// Get a link Url object from a FileLockEntry, ignore errors.
fn get_link_uri_from_filelockentry(file: &FileLockEntry<'a>) -> Option<Url> {
file.deref()
.get_header()
.read("imag.content.uri")
.ok()
.and_then(|opt| {
match opt {
Some(Value::String(s)) => Url::parse(&s[..]).ok(),
_ => None
}
})
}
#[derive(Eq, PartialEq, Clone, Debug)]
pub struct Links {
links: Vec<Link>,
}
pub fn get_url(&self) -> Result<Option<Url>> {
let opt = self.link
.deref()
.get_header()
.read("imag.content.uri");
impl Links {
pub fn new(s: Vec<Link>) -> Links {
Links { links: s }
}
pub fn add(&mut self, l: Link) {
self.links.push(l);
}
pub fn remove(&mut self, l: Link) {
self.links.retain(|link| l != link.clone());
}
pub fn all_valid(&self) -> bool {
self.links.iter().all(|l| l.is_valid())
}
}
impl Into<String> for Link {
fn into(self) -> String {
self.link
}
}
impl Into<Vec<Link>> for Links {
fn into(self) -> Vec<Link> {
self.links
}
}
pub trait ExternalLinker {
/// get the external link from the implementor object
fn get_external_link(&self) -> Result<Option<Link>>;
/// set the external link for the implementor object and return the current link from the entry,
/// if any.
fn set_external_link(&mut self, l: Link) -> Result<Option<Link>>;
}
impl ExternalLinker for EntryHeader {
fn get_external_link(&self) -> Result<Option<Link>> {
let uri = self.read("imag.content.uri");
if uri.is_err() {
let kind = LinkErrorKind::EntryHeaderReadError;
let lerr = LinkError::new(kind, Some(Box::new(uri.err().unwrap())));
return Err(lerr);
}
let uri = uri.unwrap();
match uri {
Some(Value::String(s)) => Ok(Some(Link::new(s))),
_ => Err(LinkError::new(LinkErrorKind::ExistingLinkTypeWrong, None)),
}
}
/// Set an external link in the header
///
/// Return the previous set link if there was any
fn set_external_link(&mut self, l: Link) -> Result<Option<Link>> {
if !l.is_valid() {
return Err(LinkError::new(LinkErrorKind::InvalidUri, None));
}
let old_link = self.set("imag.content.uri", Value::String(l.into()));
if old_link.is_err() {
let kind = LinkErrorKind::EntryHeaderWriteError;
let lerr = LinkError::new(kind, Some(Box::new(old_link.err().unwrap())));
return Err(lerr);
}
let old_link = old_link.unwrap();
if old_link.is_none() {
return Ok(None);
}
match old_link.unwrap() {
Value::String(s) => Ok(Some(Link::new(s))),
// We don't do anything in this case and be glad we corrected the type error with this set()
_ => Ok(None),
match opt {
Ok(Some(Value::String(s))) => {
Url::parse(&s[..])
.map(|s| Some(s))
.map_err(|e| LE::new(LEK::EntryHeaderReadError, Some(Box::new(e))))
},
Ok(None) => Ok(None),
_ => Err(LE::new(LEK::EntryHeaderReadError, None))
}
}
}
pub trait ExternalLinker : InternalLinker {
/// Get the external links from the implementor object
fn get_external_links(&self) -> Result<Vec<Url>>;
/// Set the external links for the implementor object
fn set_external_links(&mut self, links: Vec<Url>) -> Result<Vec<Url>>;
/// Add an external link to the implementor object
fn add_external_link(&mut self, link: Url) -> Result<()>;
/// Remove an external link from the implementor object
fn remove_external_link(&mut self, link: Url) -> Result<()>;
}
/// Implement ExternalLinker for Entry, hiding the fact that there is no such thing as an external
/// link in an entry, but internal links to other entries which serve as external links, as one
/// entry in the store can only have one external link.
impl ExternalLinker for Entry {
fn get_external_link(&self) -> Result<Option<Link>> {
self.get_header().get_external_link()
/// Get the external links from the implementor object
fn get_external_links(&self) -> Result<Vec<Url>> {
// Iterate through all internal links and filter for FileLockEntries which live in
// /link/external/<SHA> -> load these files and get the external link from their headers,
// put them into the return vector.
unimplemented!()
}
fn set_external_link(&mut self, l: Link) -> Result<Option<Link>> {
self.get_header_mut().set_external_link(l)
/// Set the external links for the implementor object
fn set_external_links(&mut self, links: Vec<Url>) -> Result<Vec<Url>> {
// Take all the links, generate a SHA sum out of each one, filter out the already existing
// store entries and store the other URIs in the header of one FileLockEntry each, in
// the path /link/external/<SHA of the URL>
unimplemented!()
}
/// Add an external link to the implementor object
fn add_external_link(&mut self, link: Url) -> Result<()> {
// get external links, add this one, save them
unimplemented!()
}
/// Remove an external link from the implementor object
fn remove_external_link(&mut self, link: Url) -> Result<()> {
// get external links, remove this one, save them
unimplemented!()
}
}