resource: Support embedded the resources

We detect the content of the share/ tree at build time and embed files into it.
Symbolic links to files will be followed and the target will be embedded.

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>

1 files changed, 15 insertions, 3 deletions

diff --git a/src/resource.rs b/src/resource.rs
index 3d65c68..2c1df0a 100644
--- a/src/resource.rs
+++ b/src/resource.rs
@@ -5,7 +5,7 @@
 //! binary, from template paths given on the CLI, or from paths built into the
 //! binary and present on disk.
 
-use std::io::{self, Read};
+use std::io::{self, Cursor, Read};
 use std::path::{Path, PathBuf};
 use std::sync::Mutex;
 use structopt::StructOpt;
@@ -43,6 +43,8 @@ lazy_static! {
     };
 }
 
+static EMBEDDED_FILES: &[(&str, &[u8])] = include!(concat!(env!("OUT_DIR"), "/embedded_files.inc"));
+
 /// Put a path at the back of the queue to search in
 pub fn add_search_path<P: AsRef<Path>>(path: P) {
     SEARCH_PATHS
@@ -53,7 +55,7 @@ pub fn add_search_path<P: AsRef<Path>>(path: P) {
 
 /// Open a file for reading, honouring search paths established during
 /// startup, and falling back to potentially embedded file content
-pub fn open<P: AsRef<Path>>(subpath: P) -> io::Result<Box<impl Read>> {
+pub fn open<P: AsRef<Path>>(subpath: P) -> io::Result<Box<dyn Read>> {
     let subpath = subpath.as_ref();
     let search_paths = SEARCH_PATHS.lock().expect("Unable to lock SEARCH_PATHS");
     let search_paths = search_paths.iter().map(|p| p.as_path());
@@ -71,7 +73,17 @@ pub fn open<P: AsRef<Path>>(subpath: P) -> io::Result<Box<impl Read>> {
             break;
         }
     }
-    Ok(Box::new(ret?))
+
+    match ret {
+        Ok(ret) => Ok(Box::new(ret)),
+        Err(e) => {
+            if let Some(data) = EMBEDDED_FILES.iter().find(|e| Path::new(e.0) == subpath) {
+                Ok(Box::new(Cursor::new(data.1)))
+            } else {
+                Err(e)
+            }
+        }
+    }
 }
 
 /// Read a file, honouring search paths established during startup, and