242 lines
9.1 KiB
Rust
242 lines
9.1 KiB
Rust
/// 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::ops::DerefMut;
|
|
use std::collections::BTreeMap;
|
|
|
|
use libimagstore::store::Entry;
|
|
use libimagstore::store::FileLockEntry;
|
|
use libimagstore::store::Store;
|
|
use libimagstore::storeid::StoreId;
|
|
use libimagstore::storeid::IntoStoreId;
|
|
|
|
use error::LinkError as LE;
|
|
use error::LinkErrorKind as LEK;
|
|
use result::Result;
|
|
use internal::InternalLinker;
|
|
use module_path::ModuleEntryPath;
|
|
|
|
use toml::Value;
|
|
use url::Url;
|
|
use crypto::sha1::Sha1;
|
|
use crypto::digest::Digest;
|
|
|
|
/// "Link" Type, just an abstraction over `FileLockEntry` to have some convenience internally.
|
|
struct Link<'a> {
|
|
link: FileLockEntry<'a>
|
|
}
|
|
|
|
impl<'a> Link<'a> {
|
|
|
|
pub fn new(fle: FileLockEntry<'a>) -> Link<'a> {
|
|
Link { link: fle }
|
|
}
|
|
|
|
/// 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.get_header()
|
|
.read("imag.content.uri")
|
|
.ok()
|
|
.and_then(|opt| {
|
|
match opt {
|
|
Some(Value::String(s)) => Url::parse(&s[..]).ok(),
|
|
_ => None
|
|
}
|
|
})
|
|
}
|
|
|
|
pub fn get_url(&self) -> Result<Option<Url>> {
|
|
let opt = self.link
|
|
.get_header()
|
|
.read("imag.content.uri");
|
|
|
|
match opt {
|
|
Ok(Some(Value::String(s))) => {
|
|
Url::parse(&s[..])
|
|
.map(Some)
|
|
.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, store: &Store) -> Result<Vec<Url>>;
|
|
|
|
/// Set the external links for the implementor object
|
|
fn set_external_links(&mut self, store: &Store, links: Vec<Url>) -> Result<()>;
|
|
|
|
/// Add an external link to the implementor object
|
|
fn add_external_link(&mut self, store: &Store, link: Url) -> Result<()>;
|
|
|
|
/// Remove an external link from the implementor object
|
|
fn remove_external_link(&mut self, store: &Store, link: Url) -> Result<()>;
|
|
|
|
}
|
|
|
|
/// Check whether the StoreId starts with `/link/external/`
|
|
pub fn is_external_link_storeid(id: &StoreId) -> bool {
|
|
debug!("Checking whether this is a /link/external/*: '{:?}'", id);
|
|
id.starts_with("/link/external/")
|
|
}
|
|
|
|
fn get_external_link_from_file(entry: &FileLockEntry) -> Result<Url> {
|
|
Link::get_link_uri_from_filelockentry(entry) // TODO: Do not hide error by using this function
|
|
.ok_or(LE::new(LEK::StoreReadError, None))
|
|
}
|
|
|
|
/// 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 {
|
|
|
|
/// Get the external links from the implementor object
|
|
fn get_external_links(&self, store: &Store) -> 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.
|
|
self.get_internal_links()
|
|
.map(|vect| {
|
|
debug!("Getting external links");
|
|
vect.into_iter()
|
|
.filter(is_external_link_storeid)
|
|
.map(|id| {
|
|
debug!("Retrieving entry for id: '{:?}'", id);
|
|
match store.retrieve(id.clone()) {
|
|
Ok(f) => get_external_link_from_file(&f),
|
|
Err(e) => {
|
|
debug!("Retrieving entry for id: '{:?}' failed", id);
|
|
Err(LE::new(LEK::StoreReadError, Some(Box::new(e))))
|
|
}
|
|
}
|
|
})
|
|
.filter_map(|x| x.ok()) // TODO: Do not ignore error here
|
|
.collect()
|
|
})
|
|
.map_err(|e| LE::new(LEK::StoreReadError, Some(Box::new(e))))
|
|
}
|
|
|
|
/// Set the external links for the implementor object
|
|
fn set_external_links(&mut self, store: &Store, links: Vec<Url>) -> Result<()> {
|
|
// 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>
|
|
|
|
debug!("Iterating {} links = {:?}", links.len(), links);
|
|
for link in links { // for all links
|
|
let hash = {
|
|
let mut s = Sha1::new();
|
|
s.input_str(&link.as_str()[..]);
|
|
s.result_str()
|
|
};
|
|
let file_id = ModuleEntryPath::new(format!("external/{}", hash)).into_storeid();
|
|
|
|
debug!("Link = '{:?}'", link);
|
|
debug!("Hash = '{:?}'", hash);
|
|
debug!("StoreId = '{:?}'", file_id);
|
|
|
|
// retrieve the file from the store, which implicitely creates the entry if it does not
|
|
// exist
|
|
let file = store.retrieve(file_id.clone());
|
|
if file.is_err() {
|
|
debug!("Failed to create or retrieve an file for this link '{:?}'", link);
|
|
return Err(LE::new(LEK::StoreWriteError, Some(Box::new(file.unwrap_err()))));
|
|
}
|
|
let mut file = file.unwrap();
|
|
|
|
debug!("Generating header content!");
|
|
{
|
|
let mut hdr = file.deref_mut().get_header_mut();
|
|
|
|
let mut table = match hdr.read("imag.content") {
|
|
Ok(Some(Value::Table(table))) => table,
|
|
Ok(Some(_)) => {
|
|
warn!("There is a value at 'imag.content' which is not a table.");
|
|
warn!("Going to override this value");
|
|
BTreeMap::new()
|
|
},
|
|
Ok(None) => BTreeMap::new(),
|
|
Err(e) => return Err(LE::new(LEK::StoreWriteError, Some(Box::new(e)))),
|
|
};
|
|
|
|
let v = Value::String(link.into_string());
|
|
|
|
debug!("setting URL = '{:?}", v);
|
|
table.insert(String::from("url"), v);
|
|
|
|
if let Err(e) = hdr.set("imag.content", Value::Table(table)) {
|
|
return Err(LE::new(LEK::StoreWriteError, Some(Box::new(e))));
|
|
} else {
|
|
debug!("Setting URL worked");
|
|
}
|
|
}
|
|
|
|
// then add an internal link to the new file or return an error if this fails
|
|
if let Err(e) = self.add_internal_link(file.deref_mut()) {
|
|
debug!("Error adding internal link");
|
|
return Err(LE::new(LEK::StoreWriteError, Some(Box::new(e))));
|
|
}
|
|
}
|
|
debug!("Ready iterating");
|
|
Ok(())
|
|
}
|
|
|
|
/// Add an external link to the implementor object
|
|
fn add_external_link(&mut self, store: &Store, link: Url) -> Result<()> {
|
|
// get external links, add this one, save them
|
|
debug!("Getting links");
|
|
self.get_external_links(store)
|
|
.and_then(|mut links| {
|
|
debug!("Adding link = '{:?}' to links = {:?}", link, links);
|
|
links.push(link);
|
|
debug!("Setting {} links = {:?}", links.len(), links);
|
|
self.set_external_links(store, links)
|
|
})
|
|
}
|
|
|
|
/// Remove an external link from the implementor object
|
|
fn remove_external_link(&mut self, store: &Store, link: Url) -> Result<()> {
|
|
// get external links, remove this one, save them
|
|
self.get_external_links(store)
|
|
.and_then(|links| {
|
|
debug!("Removing link = '{:?}' from links = {:?}", link, links);
|
|
let links = links.into_iter()
|
|
.filter(|l| l.as_str() != link.as_str())
|
|
.collect();
|
|
self.set_external_links(store, links)
|
|
})
|
|
}
|
|
|
|
}
|
|
|