fix(cli): bundle report templates when installed from crates.io (#877)

The build script zipped ../templates, which is outside the crate root
and therefore missing from the published package; cargo install builds
then embedded an empty zip, so ~/.fontspector was never populated and
--html/--ghmarkdown failed with TemplateNotFound. Move the templates
into the crate so they are packaged, write the zip to a growable
buffer instead of a fixed 64KB array (which also embedded trailing
zero padding), and fail the build if no templates are found.

Fixes #722, fixes #119

Author: jakefleming

fontspector-cli/build.rs

@@ -17,37 +17,37 @@ use zip::{write::SimpleFileOptions, ZipWriter};
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     ShadowBuilder::builder().build()?;
 
-    let walkdir = WalkDir::new("../templates");
+    let walkdir = WalkDir::new("templates");
     let it = walkdir.into_iter();
-    let mut buf = [0; 65536];
     let options = SimpleFileOptions::default();
-    let mut zip = ZipWriter::new(std::io::Cursor::new(&mut buf[..]));
+    let mut zip = ZipWriter::new(std::io::Cursor::new(Vec::new()));
     let mut buffer = Vec::new();
+    let mut files_added = 0;
     for entry in it.flatten() {
         let path = entry.path();
-        #[allow(clippy::unwrap_used)] // We put .. in there ourselves.
-        let name = path.strip_prefix("..").unwrap();
-        let path_as_string = name
+        let path_as_string = path
             .to_str()
             .map(str::to_owned)
-            .unwrap_or_else(|| panic!("{name:?} Is a Non UTF-8 Path"));
+            .unwrap_or_else(|| panic!("{path:?} Is a Non UTF-8 Path"));
         if path.is_file() {
-            println!("adding file {path:?} as {name:?} ...");
+            println!("adding file {path:?} ...");
             zip.start_file(path_as_string, options)?;
             let mut f = File::open(path)?;
 
             f.read_to_end(&mut buffer)?;
             zip.write_all(&buffer)?;
             buffer.clear();
-            println!("cargo:rerun-if-changed={path:?}");
-        } else if !name.as_os_str().is_empty() {
-            // Only if not root! Avoids path spec / warning
-            // and mapname conversion failed error on unzip
-            println!("adding dir {path_as_string:?} as {name:?} ...");
+            files_added += 1;
+            println!("cargo:rerun-if-changed={}", path.display());
+        } else {
+            println!("adding dir {path_as_string:?} ...");
             zip.add_directory(path_as_string, options)?;
         }
     }
-    zip.finish()?;
+    if files_added == 0 {
+        return Err("No report templates found in the templates directory".into());
+    }
+    let buf = zip.finish()?.into_inner();
     #[allow(clippy::unwrap_used)] // We're a build script, we expect OUT_DIR to be set.
     let path = Path::new(&env::var("OUT_DIR").unwrap()).join("templates.rs");
     let mut file = BufWriter::new(File::create(path)?);