refactor: simplify to single range handler

src/routes/mod.rs

@@ -9,10 +9,8 @@ use crate::settings::Settings;
 #[cfg(feature = "void-cat-redirects")]
 use crate::void_db::VoidCatDb;
 use anyhow::Error;
-use http_range_header::{
-    parse_range_header, EndPosition, StartPosition, SyntacticallyCorrectRange,
-};
-use log::{debug, warn};
+use http_range_header::{parse_range_header, EndPosition, StartPosition};
+use log::warn;
 use nostr::Event;
 use rocket::fs::NamedFile;
 use rocket::http::{ContentType, Header, Status};
@@ -22,6 +20,7 @@ use rocket::response::Responder;
 use rocket::serde::Serialize;
 use rocket::{Request, Response, State};
 use std::io::SeekFrom;
+use std::ops::Range;
 use std::pin::{pin, Pin};
 use std::str::FromStr;
 use std::task::{Context, Poll};
@@ -104,21 +103,19 @@ impl Nip94Event {
 /// Range request handler over file handle
 struct RangeBody {
     file: File,
-    file_size: u64,
-    ranges: Vec<SyntacticallyCorrectRange>,
-    current_range_index: usize,
+    range_start: u64,
+    range_end: u64,
     current_offset: u64,
     poll_complete: bool,
 }
 
 impl RangeBody {
-    pub fn new(file: File, file_size: u64, ranges: Vec<SyntacticallyCorrectRange>) -> Self {
+    pub fn new(file: File, range: Range<u64>) -> Self {
         Self {
             file,
-            file_size,
-            ranges,
+            range_start: range.start,
+            range_end: range.end,
             current_offset: 0,
-            current_range_index: 0,
             poll_complete: false,
         }
     }
@@ -130,36 +127,22 @@ impl AsyncRead for RangeBody {
         cx: &mut Context<'_>,
         buf: &mut ReadBuf<'_>,
     ) -> Poll<std::io::Result<()>> {
-        if self.current_range_index >= self.ranges.len() {
-            return Poll::Ready(Ok(()));
-        }
-
-        let current_range = &self.ranges[self.current_range_index];
-        let start_pos = match current_range.start {
-            StartPosition::Index(i) => i,
-            StartPosition::FromLast(i) => self.file_size - i,
-        };
-        let end_pos = match current_range.end {
-            EndPosition::Index(i) => i,
-            EndPosition::LastByte => self.file_size,
-        };
-        let range_start = start_pos + self.current_offset;
-        let range_len = end_pos - range_start;
+        let range_start = self.range_start + self.current_offset;
+        let range_len = self.range_end - range_start;
         let bytes_to_read = buf.remaining().min(range_len as usize) as u64;
 
         if bytes_to_read == 0 {
-            self.current_offset = 0;
-            self.current_range_index += 1;
-            return self.poll_read(cx, buf);
+            return Poll::Ready(Ok(()));
         }
 
+        // when no pending poll, seek to starting position
         if !self.poll_complete {
-            // start seeking to our read position
             let pinned = pin!(&mut self.file);
             pinned.start_seek(SeekFrom::Start(range_start))?;
             self.poll_complete = true;
         }
 
+        // check poll completion
         if self.poll_complete {
             let pinned = pin!(&mut self.file);
             match pinned.poll_complete(cx) {
@@ -173,13 +156,16 @@ impl AsyncRead for RangeBody {
 
         // Read data from the file
         let pinned = pin!(&mut self.file);
-        let n = pinned.poll_read(cx, buf);
-        if let Poll::Ready(Ok(())) = n {
-            self.current_offset += bytes_to_read;
-            Poll::Ready(Ok(()))
-        } else {
-            self.poll_complete = true;
-            Poll::Pending
+        match pinned.poll_read(cx, buf) {
+            Poll::Ready(Ok(_)) => {
+                self.current_offset += bytes_to_read;
+                Poll::Ready(Ok(()))
+            }
+            Poll::Ready(Err(e)) => Poll::Ready(Err(e)),
+            Poll::Pending => {
+                self.poll_complete = true;
+                Poll::Pending
+            }
         }
     }
 }
@@ -198,6 +184,7 @@ impl<'r> Responder<'r, 'static> for FilePayload {
                         warn!("Multipart ranges are not supported, fallback to non-range request");
                         response.set_streamed_body(self.file);
                     } else {
+                        const MAX_UNBOUNDED_RANGE: u64 = 1024 * 256;
                         let single_range = ranges.ranges.first().unwrap();
                         let range_start = match single_range.start {
                             StartPosition::Index(i) => i,
@@ -205,17 +192,18 @@ impl<'r> Responder<'r, 'static> for FilePayload {
                         };
                         let range_end = match single_range.end {
                             EndPosition::Index(i) => i,
-                            EndPosition::LastByte => self.info.size,
+                            EndPosition::LastByte => {
+                                (range_start + MAX_UNBOUNDED_RANGE).min(self.info.size)
+                            }
                         };
-                        debug!("Range: {:?} {:?}", range_start..range_end, single_range);
                         let r_len = range_end - range_start;
-                        let r_body = RangeBody::new(self.file, self.info.size, ranges.ranges);
+                        let r_body = RangeBody::new(self.file, range_start..range_end);
 
                         response.set_status(Status::PartialContent);
                         response.set_header(Header::new("content-length", r_len.to_string()));
                         response.set_header(Header::new(
                             "content-range",
-                            format!("bytes {}-{}/{}", range_start, range_end, self.info.size),
+                            format!("bytes {}-{}/{}", range_start, range_end - 1, self.info.size),
                         ));
                         response.set_streamed_body(Box::pin(r_body));
                     }