Remove DataSlice, fix #12249

8 files changed, 54 insertions, 119 deletions

diff --git a/components/script/dom/blob.rs b/components/script/dom/blob.rs
index 1bc0498fb35..8e9e96322d9 100644
--- a/components/script/dom/blob.rs
+++ b/components/script/dom/blob.rs
@@ -19,71 +19,15 @@ use net_traits::blob_url_store::BlobURLStoreEntry;
 use net_traits::filemanager_thread::{FileManagerThreadMsg, SelectedFileId, RelativePos};
 use std::ascii::AsciiExt;
 use std::cell::Cell;
-use std::ops::Range;
-use std::sync::Arc;
-
-#[derive(Clone, JSTraceable)]
-pub struct DataSlice {
-    bytes: Arc<Vec<u8>>,
-    bytes_start: usize,
-    bytes_end: usize
-}
-
-impl DataSlice {
-    /// Construct DataSlice from reference counted bytes
-    pub fn new(bytes: Arc<Vec<u8>>, start: Option<i64>, end: Option<i64>) -> DataSlice {
-        let range = RelativePos::from_opts(start, end).to_abs_range(bytes.len());
-
-        DataSlice {
-            bytes: bytes,
-            bytes_start: range.start,
-            bytes_end: range.end,
-        }
-    }
-
-    /// Construct data slice from a vector of bytes
-    pub fn from_bytes(bytes: Vec<u8>) -> DataSlice {
-        DataSlice::new(Arc::new(bytes), None, None)
-    }
-
-    /// Construct an empty data slice
-    pub fn empty() -> DataSlice {
-        DataSlice {
-            bytes: Arc::new(Vec::new()),
-            bytes_start: 0,
-            bytes_end: 0,
-        }
-    }
-
-    /// Get sliced bytes
-    pub fn get_bytes(&self) -> &[u8] {
-        &self.bytes[self.bytes_start..self.bytes_end]
-    }
-
-    /// Get length of sliced bytes
-    pub fn size(&self) -> u64 {
-        (self.bytes_end as u64) - (self.bytes_start as u64)
-    }
-
-    /// Further adjust the slice range based on passed-in relative positions
-    pub fn slice(&self, pos: &RelativePos) -> DataSlice {
-        let old_size = self.size();
-        let range = pos.to_abs_range(old_size as usize);
-        DataSlice {
-            bytes: self.bytes.clone(),
-            bytes_start: self.bytes_start + range.start,
-            bytes_end: self.bytes_start + range.end,
-        }
-    }
-}
+use std::ops::Index;
 
 #[must_root]
 #[derive(JSTraceable)]
 pub enum BlobImpl {
     /// File-based blob, including id and possibly cached content
-    File(SelectedFileId, DOMRefCell<Option<DataSlice>>),
+    File(SelectedFileId, DOMRefCell<Option<Vec<u8>>>),
     /// Memory-based blob
-    Memory(DataSlice),
+    Memory(Vec<u8>),
     /// Sliced blob, including parent blob and
     /// relative positions representing current slicing range,
     /// it is leaf of a two-layer fat tree
@@ -91,20 +35,16 @@ pub enum BlobImpl {
 }
 
 impl BlobImpl {
-    /// Construct memory-backed BlobImpl from DataSlice
-    pub fn new_from_slice(slice: DataSlice) -> BlobImpl {
-        BlobImpl::Memory(slice)
+    /// Construct memory-backed BlobImpl
+    #[allow(unrooted_must_root)]
+    pub fn new_from_bytes(bytes: Vec<u8>) -> BlobImpl {
+        BlobImpl::Memory(bytes)
     }
 
     /// Construct file-backed BlobImpl from File ID
     pub fn new_from_file(file_id: SelectedFileId) -> BlobImpl {
         BlobImpl::File(file_id, DOMRefCell::new(None))
     }
-
-    /// Construct empty, memory-backed BlobImpl
-    pub fn new_from_empty_slice() -> BlobImpl {
-        BlobImpl::new_from_slice(DataSlice::empty())
-    }
 }
 
 // https://w3c.github.io/FileAPI/#blob
@@ -178,12 +118,11 @@ impl Blob {
             }
         };
 
-        let slice = DataSlice::from_bytes(bytes);
-        Ok(Blob::new(global, BlobImpl::new_from_slice(slice), blobPropertyBag.get_typestring()))
+        Ok(Blob::new(global, BlobImpl::new_from_bytes(bytes), blobPropertyBag.get_typestring()))
     }
 
     /// Get a slice to inner data, this might incur synchronous read and caching
-    pub fn get_slice(&self) -> Result<DataSlice, ()> {
+    pub fn get_bytes(&self) -> Result<Vec<u8>, ()> {
         match *self.blob_impl.borrow() {
             BlobImpl::File(ref id, ref cached) => {
                 let buffer = match *cached.borrow() {
@@ -204,17 +143,14 @@ impl Blob {
             }
             BlobImpl::Memory(ref s) => Ok(s.clone()),
             BlobImpl::Sliced(ref parent, ref rel_pos) => {
-                let dataslice = parent.get_slice_or_empty();
-                Ok(dataslice.slice(rel_pos))
+                parent.get_bytes().map(|v| {
+                    let range = rel_pos.to_abs_range(v.len());
+                    v.index(range).to_vec()
+                })
             }
         }
     }
 
-    /// Try to get a slice, and if any exception happens, return the empty slice
-    pub fn get_slice_or_empty(&self) -> DataSlice {
-        self.get_slice().unwrap_or(DataSlice::empty())
-    }
-
     pub fn get_id(&self) -> SelectedFileId {
         match *self.blob_impl.borrow() {
             BlobImpl::File(ref id, _) => id.clone(),
@@ -228,8 +164,8 @@ impl Blob {
                     }
                     BlobImpl::File(ref parent_id, _) =>
                         self.create_sliced_id(parent_id, rel_pos),
-                    BlobImpl::Memory(ref parent_slice) => {
-                        let parent_id = parent.promote_to_file(parent_slice);
+                    BlobImpl::Memory(ref bytes) => {
+                        let parent_id = parent.promote_to_file(bytes);
                         *self.blob_impl.borrow_mut() = BlobImpl::Sliced(parent.clone(), rel_pos.clone());
                         self.create_sliced_id(&parent_id, rel_pos)
                     }
@@ -240,15 +176,10 @@ impl Blob {
 
     /// Promite memory-based Blob to file-based,
     /// The bytes in data slice will be transferred to file manager thread
-    fn promote_to_file(&self, self_slice: &DataSlice) -> SelectedFileId {
+    fn promote_to_file(&self, bytes: &[u8]) -> SelectedFileId {
         let global = self.global();
         let origin = global.r().get_url().origin().unicode_serialization();
         let filemanager = global.r().resource_threads().sender();
-        let bytes = self_slice.get_bytes();
-        let rel_pos = RelativePos::from_abs_range(Range {
-                            start: self_slice.bytes_start,
-                            end: self_slice.bytes_end,
-                        }, self_slice.bytes.len());
 
         let entry = BlobURLStoreEntry {
             type_string: self.typeString.clone(),
@@ -257,7 +188,7 @@ impl Blob {
         };
 
         let (tx, rx) = ipc::channel().unwrap();
-        let _ = filemanager.send(FileManagerThreadMsg::TransferMemory(entry, rel_pos, tx, origin.clone()));
+        let _ = filemanager.send(FileManagerThreadMsg::TransferMemory(entry, tx, origin.clone()));
 
         match rx.recv().unwrap() {
             Ok(new_id) => SelectedFileId(new_id.0),
@@ -285,7 +216,7 @@ impl Blob {
     }
 }
 
-fn read_file(global: GlobalRef, id: SelectedFileId) -> Result<DataSlice, ()> {
+fn read_file(global: GlobalRef, id: SelectedFileId) -> Result<Vec<u8>, ()> {
     let file_manager = global.filemanager_thread();
     let (chan, recv) = ipc::channel().map_err(|_|())?;
     let origin = global.get_url().origin().unicode_serialization();
@@ -300,8 +231,7 @@ fn read_file(global: GlobalRef, id: SelectedFileId) -> Result<DataSlice, ()> {
         }
     };
 
-    let bytes = result.map_err(|_|())?;
-    Ok(DataSlice::from_bytes(bytes))
+    result.map_err(|_|())
 }
 
 /// Extract bytes from BlobParts, used by Blob and File constructor
@@ -316,7 +246,8 @@ pub fn blob_parts_to_bytes(blobparts: Vec<BlobOrString>) -> Result<Vec<u8>, ()>
                 ret.append(&mut bytes);
             },
             &BlobOrString::Blob(ref b) => {
-                ret.append(&mut b.get_slice_or_empty().bytes.to_vec());
+                let mut bytes = b.get_bytes().unwrap_or(vec![]);
+                ret.append(&mut bytes);
             },
         }
     }
@@ -327,7 +258,11 @@ pub fn blob_parts_to_bytes(blobparts: Vec<BlobOrString>) -> Result<Vec<u8>, ()>
 impl BlobMethods for Blob {
     // https://w3c.github.io/FileAPI/#dfn-size
     fn Size(&self) -> u64 {
-        self.get_slice_or_empty().size()
+        // XXX: This will incur reading if file-based
+        match self.get_bytes() {
+            Ok(s) => s.len() as u64,
+            _ => 0,
+        }
     }
 
     // https://w3c.github.io/FileAPI/#dfn-type
diff --git a/components/script/dom/file.rs b/components/script/dom/file.rs
index bfc6b886282..75f73aeda59 100644
--- a/components/script/dom/file.rs
+++ b/components/script/dom/file.rs
@@ -10,7 +10,7 @@ use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
-use dom::blob::{Blob, BlobImpl, DataSlice, blob_parts_to_bytes};
+use dom::blob::{Blob, BlobImpl, blob_parts_to_bytes};
 use dom::window::Window;
 use net_traits::filemanager_thread::SelectedFile;
 use time;
@@ -71,9 +71,8 @@ impl File {
         let ref blobPropertyBag = filePropertyBag.parent;
         let typeString = blobPropertyBag.get_typestring();
 
-        let slice = DataSlice::from_bytes(bytes);
         let modified = filePropertyBag.lastModified;
-        Ok(File::new(global, BlobImpl::new_from_slice(slice), filename, modified, &typeString))
+        Ok(File::new(global, BlobImpl::new_from_bytes(bytes), filename, modified, &typeString))
     }
 
     pub fn name(&self) -> &DOMString {
diff --git a/components/script/dom/filereader.rs b/components/script/dom/filereader.rs
index 9e3f4674fa1..634f2facafe 100644
--- a/components/script/dom/filereader.rs
+++ b/components/script/dom/filereader.rs
@@ -13,7 +13,7 @@ use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::DOMString;
-use dom::blob::{Blob, DataSlice};
+use dom::blob::Blob;
 use dom::domexception::{DOMErrorName, DOMException};
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
@@ -27,6 +27,7 @@ use script_runtime::ScriptThreadEventCategory::FileRead;
 use script_runtime::{ScriptChan, CommonScriptMsg};
 use script_thread::Runnable;
 use std::cell::Cell;
+use std::sync::Arc;
 use string_cache::Atom;
 use util::thread::spawn_named;
 
@@ -160,7 +161,7 @@ impl FileReader {
 
     // https://w3c.github.io/FileAPI/#dfn-readAsText
     pub fn process_read_eof(filereader: TrustedFileReader, gen_id: GenerationId,
-                            data: ReadMetaData, blob_contents: DataSlice) {
+                            data: ReadMetaData, blob_contents: Arc<Vec<u8>>) {
         let fr = filereader.root();
 
         macro_rules! return_on_abort(
@@ -176,12 +177,11 @@ impl FileReader {
         fr.change_ready_state(FileReaderReadyState::Done);
         // Step 8.2
 
-        let bytes = blob_contents.get_bytes();
         let output = match data.function {
             FileReaderFunction::ReadAsDataUrl =>
-                FileReader::perform_readasdataurl(data, bytes),
+                FileReader::perform_readasdataurl(data, &blob_contents),
             FileReaderFunction::ReadAsText =>
-                FileReader::perform_readastext(data, bytes),
+                FileReader::perform_readastext(data, &blob_contents),
         };
 
         *fr.result.borrow_mut() = Some(output);
@@ -349,7 +349,7 @@ impl FileReader {
         self.change_ready_state(FileReaderReadyState::Loading);
 
         // Step 4
-        let blob_contents = blob.get_slice_or_empty();
+        let blob_contents = Arc::new(blob.get_bytes().unwrap_or(vec![]));
 
         let type_ = blob.Type();
 
@@ -376,7 +376,7 @@ pub enum FileReaderEvent {
     ProcessRead(TrustedFileReader, GenerationId),
     ProcessReadData(TrustedFileReader, GenerationId),
     ProcessReadError(TrustedFileReader, GenerationId, DOMErrorName),
-    ProcessReadEOF(TrustedFileReader, GenerationId, ReadMetaData, DataSlice)
+    ProcessReadEOF(TrustedFileReader, GenerationId, ReadMetaData, Arc<Vec<u8>>)
 }
 
 impl Runnable for FileReaderEvent {
@@ -400,7 +400,7 @@ impl Runnable for FileReaderEvent {
 }
 
 // https://w3c.github.io/FileAPI/#thread-read-operation
-fn perform_annotated_read_operation(gen_id: GenerationId, data: ReadMetaData, blob_contents: DataSlice,
+fn perform_annotated_read_operation(gen_id: GenerationId, data: ReadMetaData, blob_contents: Arc<Vec<u8>>,
     filereader: TrustedFileReader, script_chan: Box<ScriptChan + Send>) {
     let chan = &script_chan;
     // Step 4
diff --git a/components/script/dom/formdata.rs b/components/script/dom/formdata.rs
index 6d5b1900ec5..41168495847 100644
--- a/components/script/dom/formdata.rs
+++ b/components/script/dom/formdata.rs
@@ -126,8 +126,9 @@ impl FormData {
             Some(fname) => {
                 let global = self.global();
                 let name = DOMString::from(fname.0);
-                let slice = blob.get_slice_or_empty();
-                Root::upcast(File::new(global.r(), BlobImpl::new_from_slice(slice), name, None, ""))
+                let bytes = blob.get_bytes().unwrap_or(vec![]);
+
+                Root::upcast(File::new(global.r(), BlobImpl::new_from_bytes(bytes), name, None, ""))
             }
             None => Root::from_ref(blob)
         }
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 515d49c0f7c..fa79e25dd0a 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -324,9 +324,9 @@ impl HTMLFormElement {
                         content_disposition,
                         content_type));
 
-                    let slice = f.upcast::<Blob>().get_slice_or_empty();
+                    let bytes = &f.upcast::<Blob>().get_bytes().unwrap_or(vec![])[..];
 
-                    let decoded = encoding.decode(&slice.get_bytes(), DecoderTrap::Replace)
+                    let decoded = encoding.decode(bytes, DecoderTrap::Replace)
                                           .expect("Invalid encoding in file");
                     result.push_str(&decoded);
                 }
diff --git a/components/script/dom/testbinding.rs b/components/script/dom/testbinding.rs
index ffe8afc0b89..64fb6fb7578 100644
--- a/components/script/dom/testbinding.rs
+++ b/components/script/dom/testbinding.rs
@@ -101,7 +101,7 @@ impl TestBindingMethods for TestBinding {
     fn EnumAttribute(&self) -> TestEnum { TestEnum::_empty }
     fn SetEnumAttribute(&self, _: TestEnum) {}
     fn InterfaceAttribute(&self) -> Root<Blob> {
-        Blob::new(self.global().r(), BlobImpl::new_from_empty_slice(), "".to_owned())
+        Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned())
     }
     fn SetInterfaceAttribute(&self, _: &Blob) {}
     fn UnionAttribute(&self) -> HTMLElementOrLong { HTMLElementOrLong::Long(0) }
@@ -179,7 +179,7 @@ impl TestBindingMethods for TestBinding {
     fn SetAttr_to_automatically_rename(&self, _: DOMString) {}
     fn GetEnumAttributeNullable(&self) -> Option<TestEnum> { Some(TestEnum::_empty) }
     fn GetInterfaceAttributeNullable(&self) -> Option<Root<Blob>> {
-        Some(Blob::new(self.global().r(), BlobImpl::new_from_empty_slice(), "".to_owned()))
+        Some(Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned()))
     }
     fn SetInterfaceAttributeNullable(&self, _: Option<&Blob>) {}
     fn GetInterfaceAttributeWeak(&self) -> Option<Root<URL>> {
@@ -230,7 +230,7 @@ impl TestBindingMethods for TestBinding {
     fn ReceiveByteString(&self) -> ByteString { ByteString::new(vec!()) }
     fn ReceiveEnum(&self) -> TestEnum { TestEnum::_empty }
     fn ReceiveInterface(&self) -> Root<Blob> {
-        Blob::new(self.global().r(), BlobImpl::new_from_empty_slice(), "".to_owned())
+        Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned())
     }
     fn ReceiveAny(&self, _: *mut JSContext) -> JSVal { NullValue() }
     fn ReceiveObject(&self, _: *mut JSContext) -> *mut JSObject { panic!() }
@@ -247,7 +247,7 @@ impl TestBindingMethods for TestBinding {
     }
     fn ReceiveSequence(&self) -> Vec<i32> { vec![1] }
     fn ReceiveInterfaceSequence(&self) -> Vec<Root<Blob>> {
-        vec![Blob::new(self.global().r(), BlobImpl::new_from_empty_slice(), "".to_owned())]
+        vec![Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned())]
     }
 
     fn ReceiveNullableBoolean(&self) -> Option<bool> { Some(false) }
@@ -268,7 +268,7 @@ impl TestBindingMethods for TestBinding {
     fn ReceiveNullableByteString(&self) -> Option<ByteString> { Some(ByteString::new(vec!())) }
     fn ReceiveNullableEnum(&self) -> Option<TestEnum> { Some(TestEnum::_empty) }
     fn ReceiveNullableInterface(&self) -> Option<Root<Blob>> {
-        Some(Blob::new(self.global().r(), BlobImpl::new_from_empty_slice(), "".to_owned()))
+        Some(Blob::new(self.global().r(), BlobImpl::new_from_bytes(vec![]), "".to_owned()))
     }
     fn ReceiveNullableObject(&self, _: *mut JSContext) -> *mut JSObject { ptr::null_mut() }
     fn ReceiveNullableUnion(&self) -> Option<HTMLElementOrLong> {
diff --git a/components/script/dom/websocket.rs b/components/script/dom/websocket.rs
index cc8c6f74d54..1a34096f26b 100644
--- a/components/script/dom/websocket.rs
+++ b/components/script/dom/websocket.rs
@@ -16,7 +16,7 @@ use dom::bindings::js::Root;
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString, is_token};
-use dom::blob::{Blob, BlobImpl, DataSlice};
+use dom::blob::{Blob, BlobImpl};
 use dom::closeevent::CloseEvent;
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
@@ -405,7 +405,7 @@ impl WebSocketMethods for WebSocket {
         if send_data {
             let mut other_sender = self.sender.borrow_mut();
             let my_sender = other_sender.as_mut().unwrap();
-            let bytes = blob.get_slice_or_empty().get_bytes().to_vec();
+            let bytes = blob.get_bytes().unwrap_or(vec![]);
             let _ = my_sender.send(WebSocketDomAction::SendMessage(MessageData::Binary(bytes)));
         }
 
@@ -591,8 +591,7 @@ impl Runnable for MessageReceivedTask {
                 MessageData::Binary(data) => {
                     match ws.binary_type.get() {
                         BinaryType::Blob => {
-                            let slice = DataSlice::from_bytes(data);
-                            let blob = Blob::new(global.r(), BlobImpl::new_from_slice(slice), "".to_owned());
+                            let blob = Blob::new(global.r(), BlobImpl::new_from_bytes(data), "".to_owned());
                             blob.to_jsval(cx, message.handle_mut());
                         }
                         BinaryType::Arraybuffer => {
diff --git a/components/script/dom/xmlhttprequest.rs b/components/script/dom/xmlhttprequest.rs
index c3fc2e00dc8..9cdf47a47bb 100644
--- a/components/script/dom/xmlhttprequest.rs
+++ b/components/script/dom/xmlhttprequest.rs
@@ -20,7 +20,7 @@ use dom::bindings::js::{Root, RootedReference};
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::{ByteString, DOMString, USVString, is_token};
-use dom::blob::{Blob, DataSlice, BlobImpl};
+use dom::blob::{Blob, BlobImpl};
 use dom::document::DocumentSource;
 use dom::document::{Document, IsHTMLDocument};
 use dom::event::{Event, EventBubbles, EventCancelable};
@@ -1105,8 +1105,8 @@ impl XMLHttpRequest {
         let mime = self.final_mime_type().as_ref().map(Mime::to_string).unwrap_or("".to_owned());
 
         // Step 3, 4
-        let slice = DataSlice::from_bytes(self.response.borrow().to_vec());
-        let blob = Blob::new(self.global().r(), BlobImpl::new_from_slice(slice), mime);
+        let bytes = self.response.borrow().to_vec();
+        let blob = Blob::new(self.global().r(), BlobImpl::new_from_bytes(bytes), mime);
         self.response_blob.set(Some(blob.r()));
         blob
     }
@@ -1377,7 +1377,8 @@ impl Extractable for BodyInit {
                 } else {
                     Some(b.Type())
                 };
-                (b.get_slice_or_empty().get_bytes().to_vec(), content_type)
+                let bytes = b.get_bytes().unwrap_or(vec![]);
+                (bytes, content_type)
             },
         }
     }