Cargo templating for new and init

PR #3004 This is a resubmission of the PR #1747 (from scratch) which adds
support for templating in Cargo. The templates are implemented using the
handlebars crate (where the original PR used mustache).

Examples:
cargo new --template https://url/to/template somedir foo
cargo new --template https://url/to/templates --template-subdir somedir foo
cargo new --template ../path/to/template somedir foo

Cargo.toml

@@ -28,9 +28,11 @@ fs2 = "0.3"
 git2 = "0.6"
 git2-curl = "0.7"
 glob = "0.2"
+handlebars = "0.20"
 libc = "0.2"
 libgit2-sys = "0.6"
 log = "0.3"
+miow = "0.1"
 num_cpus = "1.0"
 regex = "0.1"
 rustc-serialize = "0.3"

src/bin/init.rs

@@ -12,6 +12,8 @@ pub struct Options {
     flag_lib: bool,
     arg_path: Option<String>,
     flag_name: Option<String>,
+    flag_template_subdir: Option<String>,
+    flag_template: Option<String>,
     flag_vcs: Option<ops::VersionControl>,
     flag_frozen: bool,
     flag_locked: bool,
@@ -32,6 +34,8 @@ Options:
     --bin               Use a binary (application) template
     --lib               Use a library template
     --name NAME         Set the resulting package name
+    --template <repository>  Use a specified template repository
+    --template-subdir <template>  Use a specified template within a template repository
     -v, --verbose ...   Use verbose output (-vv very verbose/build.rs output)
     -q, --quiet         No output printed to stdout
     --color WHEN        Coloring: auto, always, never
@@ -47,14 +51,22 @@ pub fn execute(options: Options, config: &Config) -> CliResult {
                      options.flag_frozen,
                      options.flag_locked)?;
 
-    let Options { flag_bin, flag_lib, arg_path, flag_name, flag_vcs, .. } = options;
+    let Options { 
+        flag_bin, flag_lib, 
+        arg_path, flag_name, 
+        flag_vcs, 
+        flag_template_subdir, flag_template, 
+        .. 
+    } = options;
 
     let tmp = &arg_path.unwrap_or(format!("."));
     let opts = ops::NewOptions::new(flag_vcs,
                                      flag_bin,
                                      flag_lib,
                                      tmp,
-                                     flag_name.as_ref().map(|s| s.as_ref()));
+                                     flag_name.as_ref().map(|s| s.as_ref()),
+                                     flag_template_subdir.as_ref().map(|s| s.as_ref()),
+                                     flag_template.as_ref().map(|s| s.as_ref()));
 
     let opts_lib = opts.lib;
     ops::init(opts, config)?;

src/bin/new.rs

@@ -12,6 +12,8 @@ pub struct Options {
     flag_lib: bool,
     arg_path: String,
     flag_name: Option<String>,
+    flag_template_subdir: Option<String>,
+    flag_template: Option<String>,
     flag_vcs: Option<ops::VersionControl>,
     flag_frozen: bool,
     flag_locked: bool,
@@ -32,6 +34,8 @@ Options:
     --bin               Use a binary (application) template
     --lib               Use a library template
     --name NAME         Set the resulting package name, defaults to the value of <path>
+    --template <repository>  Use a specified template repository
+    --template-subdir <template-subdir>  Use a specified template within a template repository
     -v, --verbose ...   Use verbose output (-vv very verbose/build.rs output)
     -q, --quiet         No output printed to stdout
     --color WHEN        Coloring: auto, always, never
@@ -47,13 +51,21 @@ pub fn execute(options: Options, config: &Config) -> CliResult {
                      options.flag_frozen,
                      options.flag_locked)?;
 
-    let Options { flag_bin, flag_lib, arg_path, flag_name, flag_vcs, .. } = options;
+    let Options { 
+        flag_bin, flag_lib, 
+        arg_path, flag_name, 
+        flag_vcs, 
+        flag_template_subdir, flag_template, 
+        .. 
+    } = options;
 
     let opts = ops::NewOptions::new(flag_vcs,
                                     flag_bin,
                                     flag_lib,
                                     &arg_path,
-                                    flag_name.as_ref().map(|s| s.as_ref()));
+                                    flag_name.as_ref().map(|s| s.as_ref()),
+                                    flag_template_subdir.as_ref().map(|s| s.as_ref()),
+                                    flag_template.as_ref().map(|s| s.as_ref()));
 
     let opts_lib = opts.lib;
     ops::new(opts, config)?;

src/cargo/lib.rs

@@ -12,6 +12,7 @@ extern crate flate2;
 extern crate fs2;
 extern crate git2;
 extern crate glob;
+extern crate handlebars;
 extern crate libc;
 extern crate libgit2_sys;
 extern crate num_cpus;