Bug 1219452 - Update script for rust mp4parser. r=kinetik

Automate update and patching of the rust mp4 parser from the
upstream repo. A rev for mp4parse-rust can be passed on the
command line, but the byteorder crate's version is hardcoded.

Differences to adapt to the gecko build system are applied as
patches like we do for other media code.

Unfortunately cargo isn't much help here. It can download
crates for us, and we can set CARGO_HOME to force it to
use a specific directory, but it doesn't return enough
information to get the versions, etc. without some guessing/scraping
to find the packaged source.

media/libstagefright/binding/byteorder-mod.patch

@@ -0,0 +1,37 @@
+diff --git a/media/libstagefright/binding/byteorder/mod.rs b/media/libstagefright/binding/byteorder/mod.rs
+index 59ba692..9d2d1d5 100644
+--- a/media/libstagefright/binding/byteorder/mod.rs
++++ b/media/libstagefright/binding/byteorder/mod.rs
+@@ -36,16 +36,16 @@ assert_eq!(wtr, vec![5, 2, 0, 3]);
+ ```
+ */
+ 
+-#![crate_name = "byteorder"]
+ #![doc(html_root_url = "http://burntsushi.net/rustdoc/byteorder")]
+ 
+ #![deny(missing_docs)]
+ 
+ use std::mem::transmute;
+ 
+-pub use new::{ReadBytesExt, WriteBytesExt, Error, Result};
++pub use byteorder::new::{ReadBytesExt, WriteBytesExt, Error, Result};
+ 
+-mod new;
++// Re-export new so gecko can build us as a mod intead of a crate.
++pub mod new;
+ 
+ #[inline]
+ fn extend_sign(val: u64, nbytes: usize) -> i64 {
+diff --git a/media/libstagefright/binding/byteorder/new.rs b/media/libstagefright/binding/byteorder/new.rs
+index bbef0cd..a2e5393 100644
+--- a/media/libstagefright/binding/byteorder/new.rs
++++ b/media/libstagefright/binding/byteorder/new.rs
+@@ -3,7 +3,7 @@ use std::fmt;
+ use std::io;
+ use std::result;
+ 
+-use ByteOrder;
++use byteorder::ByteOrder;
+ 
+ /// A short-hand for `result::Result<T, byteorder::Error>`.
+ pub type Result<T> = result::Result<T, Error>;

media/libstagefright/binding/mp4parse-mod.patch

@@ -0,0 +1,13 @@
+diff --git a/media/libstagefright/binding/MP4Metadata.rs b/media/libstagefright/binding/MP4Metadata.rs
+index a9ab567..b746f15 100644
+--- a/media/libstagefright/binding/MP4Metadata.rs
++++ b/media/libstagefright/binding/MP4Metadata.rs
+@@ -214,7 +214,7 @@ pub struct Track {
+     track_type: TrackType,
+ }
+ 
+-extern crate byteorder;
++mod byteorder; // 'extern crate' upstream.
+ use byteorder::{BigEndian, ReadBytesExt};
+ use std::io::{Read, BufRead, Take};
+ use std::io::Cursor;

media/libstagefright/binding/update-rust.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+# Script to update mp4parse-rust sources to latest upstream
+
+# Default version.
+VER=v0.1.2
+
+# Accept version or commit from the command line.
+if test -n "$1"; then
+  VER=$1
+fi
+
+echo "Fetching sources..."
+rm -rf _upstream
+git clone https://github.com/mozilla/mp4parse-rust _upstream/mp4parse
+pushd _upstream/mp4parse
+git checkout ${VER}
+popd
+cp _upstream/mp4parse/src/lib.rs MP4Metadata.rs
+cp _upstream/mp4parse/src/capi.rs .
+
+# TODO: download deps from crates.io.
+
+git clone https://github.com/BurntSushi/byteorder _upstream/byteorder
+pushd _upstream/byteorder
+git checkout 0.3.13
+popd
+cp _upstream/byteorder/src/lib.rs byteorder/mod.rs
+cp _upstream/byteorder/src/new.rs byteorder/new.rs
+
+echo "Applying patches..."
+patch -p4 < byteorder-mod.patch
+patch -p4 < mp4parse-mod.patch
+
+echo "Cleaning up..."
+rm -rf _upstream
+
+echo "Updated to ${VER}."