Improve lib template on Travis (#19)

* Improve lib template on Travis

This commit contains changes on the generated lib template to build
cross-platform libs. With this changes, I was able to setup a [Travis]
build with GitHub [Releases] of a cross-platform lib.

It is not possible yet to build a different crate type only using
command line args. It requires a modification on `Cargo.toml` to include
new types of library outputs. I've already opened an issue on [cargo](rust-lang/cargo#6160) to see what should be the case here.

Meanwhile, lib authors must change `Cargo.toml` and include the extra
`crate-type` attribute with all the libs. Sadly, this also means that
`LTO` optimisation is not available if the lib uses `lib` or `rlib`
attributes.

To avoid modifying the `Cargo.toml`, the sugestion would be that on a
future PR we could add to the deploy script a modification on the
`Cargo.toml` manifest to include the corresponding crate-type, and only
such crate type for that target. This means we would be able to bring
LTO and output smaller libs.

Realated to:
- #11

[Travis]: https://travis-ci.org/bltavares/rust-over-jna-example/builds/439439854
[Releases]: https://github.com/bltavares/rust-over-jna-example/releases/tag/initial

Signed-off-by: Bruno Tavares <connect+github@bltavares.com>

* Define the type of artifact to be produced by cargo.

s command `cargo` subcommand is exclusively intended to be used to help
with [working arround](rust-lang/rust#51009)
how crate types are defined, in order to help with cross-platform
builds.

It is currently [not possible](rust-lang/cargo#6160) to define a
single `crate-type` override on `cargo build`, which causes libs
intended to be used on other languages to compile more than one type of
crate.

This commit adds a dependency on this [new CLI app](https://github.com/bltavares/cargo-crate-type) to be able to workaround the limitations of Cargo.

We are now able to enable the `-C lto` optimization again, as we will
only compile a single type of artifact

Signed-off-by: Bruno Tavares <connect+github@bltavares.com>

templates/lib/before_deploy.sh

@@ -5,22 +5,38 @@ PKG_NAME="{{PKG_NAME}}"
 set -ex
 
 main() {
-  local src=$(pwd) \
-    stage=
+  local src=$(pwd) stage
 
   case $TRAVIS_OS_NAME in
-    linux)
-      stage=$(mktemp -d)
-      ;;
-    osx)
-      stage=$(mktemp -d -t tmp)
-      ;;
+  linux)
+    stage=$(mktemp -d)
+    ;;
+  osx)
+    stage=$(mktemp -d -t tmp)
+    ;;
   esac
 
   test -f Cargo.lock || cargo generate-lockfile
 
-  cross rustc --bin $PKG_NAME --target $TARGET --release -- -C lto
-  cp target/$TARGET/release/$PKG_NAME $stage/
+  if [[ "$TYPE" == "static" ]]; then
+    cargo crate-type static
+  else
+    cargo crate-type dynamic
+  fi
+
+  cross rustc --lib --target $TARGET --release -- -C lto
+
+  case $TYPE-$TRAVIS_OS_NAME in
+  static-*)
+    cp target/$TARGET/release/lib$PKG_NAME.a $stage/
+    ;;
+  *-osx)
+    cp target/$TARGET/release/lib$PKG_NAME.dylib $stage/
+    ;;
+  *)
+    cp target/$TARGET/release/lib$PKG_NAME.so $stage/
+    ;;
+  esac
 
   cd $stage
   tar czf $src/$CRATE_NAME-$TRAVIS_TAG-$TARGET.tar.gz *

templates/lib/install.sh

@@ -38,6 +38,9 @@ main() {
   # Install test dependencies
   rustup component add rustfmt-preview
   rustup component add clippy-preview
+
+  # For defining the type of lib to produce: dynamic OR static
+  cargo install --force cargo-crate-type
 }
 
 main

templates/lib/travis.yml

@@ -12,7 +12,7 @@ matrix:
   include:
     - env: TARGET=armv7-unknown-linux-gnueabihf
       rust: nightly
-    - env: TARGET=x86_64-unknown-linux-musl
+    - env: TARGET=x86_64-unknown-linux-musl TYPE=static
       rust: nightly
     - env: TARGET=x86_64-apple-darwin
       rust: nightly