Auto merge of #11536 - izgzhen:add-blob-loader, r=Manishearth

Add blob loader

Add a blob loader to implement [Blob URL](https://w3c.github.io/FileAPI/#url). The related interfaces to script thread are also declared.

Progressing in parallel with PR #11534. Related to #11131.

<!-- Please describe your changes on the following line: -->

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix part of #10539

<!-- Either: -->
- [x] These changes do not require tests because not integrated yet.

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/11536)
<!-- Reviewable:end -->

components/net_traits/blob_url_store.rs

@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use ipc_channel::ipc::IpcSender;
+use std::str::FromStr;
+use url::Url;
+use uuid::Uuid;
+
+/// Errors returns to BlobURLStoreMsg::Request
+#[derive(Clone, Serialize, Deserialize)]
+pub enum BlobURLStoreError {
+    /// Invalid UUID key
+    InvalidKey,
+    /// Invalid URL origin
+    InvalidOrigin,
+}
+
+/// Blob URL store entry, a packaged form of Blob DOM object
+#[derive(Clone, Serialize, Deserialize)]
+pub struct BlobURLStoreEntry {
+    /// MIME type string
+    pub type_string: String,
+    /// Some filename if the backend of Blob is a file
+    pub filename: Option<String>,
+    /// Size of content in bytes
+    pub size: u64,
+    /// Content of blob
+    pub bytes: Vec<u8>,
+}
+
+/// Message-passing style interface between store and loader
+#[derive(Serialize, Deserialize)]
+pub enum BlobURLStoreMsg {
+    /// Request for an blob entry identified by uuid
+    Request(Uuid, IpcSender<Result<BlobURLStoreEntry, BlobURLStoreError>>),
+}
+
+/// Parse URL as Blob URL scheme's definition
+/// https://w3c.github.io/FileAPI/#DefinitionOfScheme
+pub fn parse_blob_url(url: &Url) -> Option<(Uuid, Option<&str>)> {
+    url.path_segments().and_then(|mut segments| {
+        let id_str = match (segments.next(), segments.next()) {
+            (Some(s), None) => s,
+            _ => return None,
+        };
+
+        Uuid::from_str(id_str).map(|id| (id, url.fragment())).ok()
+    })
+}

components/net_traits/filemanager_thread.rs

@@ -4,6 +4,7 @@
 
 use ipc_channel::ipc::IpcSender;
 use std::path::PathBuf;
+use super::{LoadConsumer, LoadData};
 use uuid::Uuid;
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -29,6 +30,9 @@ pub enum FileManagerThreadMsg {
     /// Delete the FileID entry
     DeleteFileID(Uuid),
 
+    /// Load resource by Blob URL
+    LoadBlob(LoadData, LoadConsumer),
+
     /// Shut down this thread
     Exit,
 }

components/net_traits/lib.rs

@@ -43,6 +43,7 @@ use storage_thread::StorageThreadMsg;
 use url::Url;
 use websocket::header;
 
+pub mod blob_url_store;
 pub mod bluetooth_scanfilter;
 pub mod bluetooth_thread;
 pub mod filemanager_thread;