N-API Support

README.md

@@ -285,6 +285,81 @@ What will happen is this:
 
 If a a binary was not available for a given platform and `--fallback-to-build` was used then `node-gyp rebuild` will be called to try to source compile the module.
 
+## N-API Considerations
+
+[N-API](https://nodejs.org/api/n-api.html#n_api_n_api) is an ABI-stable alternative to previous technologies such as [nan](https://github.com/nodejs/nan) which are tied to a specific Node runtime engine. N-API is Node runtime engine agnostic and guarantees modules created today will continue to run, without changes, into the future. 
+
+Using `node-pre-gyp` with N-API projects requires a handful of additional congiguration values and imposes some additional requirements. 
+
+The most significant difference is that an N-API module can be coded to target multiple  N-API versions. Therefore, an N-API module must declare in its `package.json` file which N-API versions the module is designed to run against. In addition, since multiple builds may be required for a single module, path and file names must be specified in way that avoids naming conflicts. 
+
+### The `napi_versions` array property
+
+An N-API modules must declare in its `package.json` file, the N-API versions the module is intended to support. This is accomplished by including an `napi-versions` array property in the `binary` object. For example:
+
+```js
+"binary": {
+    "module_name": "your_module",
+    "module_path": "your_module_path",
+    "host": "https://your_bucket.s3-us-west-1.amazonaws.com",
+    "napi_versions": [1,3]
+  }
+```
+
+If the `napi_versions` array property is *not* present, `node-pre-gyp` operates as it always has. Including the `napi_versions` array property instructs `node-pre-gyp` that this is a N-API module build.
+
+When the `napi_versions` array property is present, `node-pre-gyp` fires off multiple operations, one for each of the N-API versions in the array. In the example above, two operations are initiated, one for N-API version 1 and second for N-API version 3. How this version number is communicated is described next. 
+
+### The `napi_build_version` value
+
+For each of the N-API module operations `node-pre-gyp` initiates, it insures that the `napi_build_version` is set appropriately. 
+
+This value is of importance in two areas:
+
+1. The C/C++ code which needs to know against which N-API version it should compile.
+2. `node-pre-gyp` itself which must assign appropriate path and file names to avoid collisions. 
+
+### Defining `NAPI_BUILD_VERSION` for the C/C++ code
+
+The `napi_build_version` value is communicated to the C/C++ code by adding this code to the `binding.gyp` file:
+
+```
+"defines": [
+    "NAPI_BUILD_VERSION=<(napi_build_version)",
+]
+```
+
+This insures that `NAPI_BUILD_VERSION`, an integer value, is declared appropriately to the C/C++ code for each build.
+
+### Path and file naming requirements in `package.json`
+
+Since `node-pre-gyp` fires off multiple operations for each request, it is essential that path and file names be created in such a way as to avoid collisions. This is accomplished by imposing additional path and file naming requirements. 
+
+Specifically, when performing N-API builds, the `{napi_build_version}` text substitution string  *must* be present in the `module_path` property. In addition, the `{napi_build_version}` text substitution string  *must* be present in either the `remote_path` or `package_name` property. (No problem if it's in both.)
+
+Here's an example:
+
+```js
+"binary": {
+    "module_name": "your_module",
+    "module_path": "./lib/binding/napi-v{napi_build_version}",
+    "remote_path": "./{module_name}/v{version}/{configuration}/",
+    "package_name": "{platform}-{arch}-napi-v{napi_build_version}.tar.gz",
+    "host": "https://your_bucket.s3-us-west-1.amazonaws.com",
+    "napi_versions": [1,3]
+  }
+```
+
+### Two additional configuration values
+
+For those who need them in legacy projects, two additional configuration values are available for all builds. 
+
+1. `napi_version` If N-API is supported by the currently executing Node instance, this value is the N-API version number supported by Node. If N-API is not supported, this value is an empty string. 
+
+2. `node_abi_napi` If the value returned for `napi_version` is non empty, this value is `'napi'`. If the value returned for `napi_version` is empty, this value is the value returned for `node_abi`.
+
+These values are present for use in the `binding.gyp` file and may be used as `{napi_version}` and `{node_abi_napi}` for text substituion in the `package.json` file. 
+
 ## S3 Hosting
 
 You can host wherever you choose but S3 is cheap, `node-pre-gyp publish` expects it, and S3 can be integrated well with [Travis.ci](http://travis-ci.org) to automate builds for OS X and Ubuntu, and with [Appveyor](http://appveyor.com) to automate builds for Windows. Here is an approach to do this:

lib/build.js

@@ -4,6 +4,7 @@ module.exports = exports = build;
 
 exports.usage = 'Attempts to compile the module by dispatching to node-gyp or nw-gyp';
 
+var napi = require('./util/napi.js');
 var compile = require('./util/compile.js');
 var handle_gyp_opts = require('./util/handle_gyp_opts.js');
 var configure = require('./configure.js');
@@ -16,7 +17,13 @@ function do_build(gyp,argv,callback) {
                           concat(['--']).
                           concat(result.unparsed);
         }
+        if (!err && result.opts.napi_build_version) {
+            napi.swap_build_dir_in(result.opts.napi_build_version);
+        }
         compile.run_gyp(final_args,result.opts,function(err) {
+            if (!err && result.opts.napi_build_version) {
+                napi.swap_build_dir_out(result.opts.napi_build_version);
+            }
             return callback(err);
         });
     });
@@ -28,6 +35,7 @@ function build(gyp, argv, callback) {
     // We map `node-pre-gyp build` to `node-gyp configure build` so that we do not
     // trigger a clean and therefore do not pay the penalty of a full recompile
     if (argv.length && (argv.indexOf('rebuild') > -1)) {
+        argv.shift(); // remove `rebuild`
         // here we map `node-pre-gyp rebuild` to `node-gyp rebuild` which internally means
         // "clean + configure + build" and triggers a full recompile
         compile.run_gyp(['clean'],{},function(err) {

lib/clean.js

@@ -8,10 +8,12 @@ var fs = require('fs');
 var rm = require('rimraf');
 var exists = require('fs').exists || require('path').exists;
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
 
 function clean (gyp, argv, callback) {
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
-    var opts = versioning.evaluate(package_json, gyp.opts);
+    var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
+    var opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
     var to_delete = opts.module_path;
     exists(to_delete, function(found) {
         if (found) {

lib/configure.js

@@ -4,6 +4,7 @@ module.exports = exports = configure;
 
 exports.usage = 'Attempts to configure node-gyp or nw-gyp build';
 
+var napi = require('./util/napi.js');
 var compile = require('./util/compile.js');
 var handle_gyp_opts = require('./util/handle_gyp_opts.js');
 
@@ -41,6 +42,9 @@ function configure(gyp, argv, callback) {
                               concat(result.unparsed);
             }
             compile.run_gyp(['configure'].concat(final_args),result.opts,function(err) {
+                if (!err && result.opts.napi_build_version) {
+                    napi.swap_build_dir_out(result.opts.napi_build_version);
+                }
                 return callback(err);
             });
         }

lib/install.js

@@ -9,6 +9,7 @@ var path = require('path');
 var log = require('npmlog');
 var existsAsync = fs.exists || path.exists;
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
 var mkdirp = require('mkdirp');
 
 var npgVersion = 'unknown';
@@ -121,7 +122,8 @@ function place_binary(from,to,opts,callback) {
 }
 
 function do_build(gyp,argv,callback) {
-  gyp.todo.push( { name: 'build', args: ['rebuild'] } );
+  var args = ['rebuild'].concat(argv);
+  gyp.todo.push( { name: 'build', args: args } );
   process.nextTick(callback);
 }
 
@@ -151,6 +153,7 @@ function print_fallback_error(err,opts,package_json) {
 
 function install(gyp, argv, callback) {
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
+	var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
     var source_build = gyp.opts['build-from-source'] || gyp.opts.build_from_source;
     var update_binary = gyp.opts['update-binary'] || gyp.opts.update_binary;
     var should_do_source_build = source_build === package_json.name || (source_build === true || source_build === 'true');
@@ -171,7 +174,7 @@ function install(gyp, argv, callback) {
         }
         var opts;
         try {
-            opts = versioning.evaluate(package_json, gyp.opts);
+            opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
         } catch (err) {
             return callback(err);
         }

lib/node-pre-gyp.js

@@ -10,10 +10,12 @@ module.exports = exports;
  * Module dependencies.
  */
 
+var fs = require('fs');
 var path = require('path');
 var nopt = require('nopt');
 var log = require('npmlog');
 log.disableProgress();
+var napi = require('./util/napi.js');
 
 var EE = require('events').EventEmitter;
 var inherits = require('util').inherits;
@@ -128,6 +130,13 @@ proto.parseArgv = function parseOpts (argv) {
     commands[commands.length - 1].args = argv.splice(0);
   }
 
+  // expand commands entries for multiple napi builds
+  var dir = this.opts.directory;
+  if (dir == null) dir = process.cwd();
+  var package_json = JSON.parse(fs.readFileSync(path.join(dir,'package.json')));
+
+  this.todo = napi.expand_commands (package_json, commands);
+
   // support for inheriting config env variables from npm
   var npm_config_prefix = 'npm_config_';
   Object.keys(process.env).forEach(function (name) {

lib/package.js

@@ -8,14 +8,17 @@ var fs = require('fs');
 var path = require('path');
 var log = require('npmlog');
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
+var write = require('fs').createWriteStream;
 var existsAsync = fs.exists || path.exists;
 var mkdirp = require('mkdirp');
 var tar = require('tar');
 
 function _package(gyp, argv, callback) {
     var packlist = require('npm-packlist');
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
-    var opts = versioning.evaluate(package_json, gyp.opts);
+    var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
+    var opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
     var from = opts.module_path;
     var binary_module = path.join(from,opts.module_name + '.node');
     existsAsync(binary_module,function(found) {

lib/pre-binding.js

@@ -1,6 +1,7 @@
 "use strict";
 
 var versioning = require('../lib/util/versioning.js');
+var napi = require('../lib/util/napi.js');
 var existsSync = require('fs').existsSync || require('path').existsSync;
 var path = require('path');
 
@@ -18,8 +19,12 @@ exports.find = function(package_json_path,opts) {
    }
    var package_json = require(package_json_path);
    versioning.validate_config(package_json);
+   var napi_build_version;
+   if (napi.get_napi_build_versions (package_json)) {
+       napi_build_version = napi.get_best_napi_build_version(package_json);
+   }
    opts = opts || {};
    if (!opts.module_root) opts.module_root = path.dirname(package_json_path);
-   var meta = versioning.evaluate(package_json,opts);
+   var meta = versioning.evaluate(package_json,opts,napi_build_version);
    return meta.module;
 };

lib/publish.js

@@ -8,6 +8,7 @@ var fs = require('fs');
 var path = require('path');
 var log = require('npmlog');
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
 var s3_setup = require('./util/s3_setup.js');
 var existsAsync = fs.exists || path.exists;
 var url = require('url');
@@ -16,7 +17,8 @@ var config = require('rc')("node_pre_gyp",{acl:"public-read"});
 function publish(gyp, argv, callback) {
     var AWS = require("aws-sdk");
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
-    var opts = versioning.evaluate(package_json, gyp.opts);
+    var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
+    var opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
     var tarball = opts.staged_tarball;
     existsAsync(tarball,function(found) {
         if (!found) {

lib/rebuild.js

@@ -4,10 +4,18 @@ module.exports = exports = rebuild;
 
 exports.usage = 'Runs "clean" and "build" at once';
 
+var fs = require('fs');
+var napi = require('./util/napi.js');
+
 function rebuild (gyp, argv, callback) {
-  gyp.todo.unshift(
-      { name: 'clean', args: [] },
-      { name: 'build', args: ['rebuild'] }
-  );
+  var package_json = JSON.parse(fs.readFileSync('./package.json'));
+  var commands = [
+    { name: 'clean', args: [] },
+    { name: 'build', args: ['rebuild'] }
+    ];
+  commands = napi.expand_commands(package_json, commands);
+  for (var i = commands.length; i !== 0; i--) {
+    gyp.todo.unshift(commands[i-1]);
+  }
   process.nextTick(callback);
 }

lib/reinstall.js

@@ -4,10 +4,17 @@ module.exports = exports = rebuild;
 
 exports.usage = 'Runs "clean" and "install" at once';
 
+var fs = require('fs');
+var napi = require('./util/napi.js');
+
 function rebuild (gyp, argv, callback) {
+  var package_json = JSON.parse(fs.readFileSync('./package.json'));
+  var installArgs = [];
+  var napi_build_version = napi.get_best_napi_version(package_json);
+  if (napi_build_version != null) installArgs = [ napi.get_command_arg (napi_build_version) ];
   gyp.todo.unshift(
       { name: 'clean', args: [] },
-      { name: 'install', args: [] }
+      { name: 'install', args: installArgs }
   );
   process.nextTick(callback);
 }

lib/reveal.js

@@ -6,19 +6,21 @@ exports.usage = 'Reveals data on the versioned binary';
 
 var fs = require('fs');
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
 
 function unix_paths(key, val) {
     return val && val.replace ? val.replace(/\\/g, '/') : val;
 }
 
 function reveal(gyp, argv, callback) {
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
-    var opts = versioning.evaluate(package_json, gyp.opts);
+    var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
+    var opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
     var hit = false;
     // if a second arg is passed look to see
     // if it is a known option
     //console.log(JSON.stringify(gyp.opts,null,1))
-    var remain = gyp.opts.argv.remain.pop();
+    var remain = gyp.opts.argv.remain[gyp.opts.argv.remain.length-1];
     if (remain && opts.hasOwnProperty(remain)) {
         console.log(opts[remain].replace(/\\/g, '/'));
         hit = true;

lib/testbinary.js

@@ -9,14 +9,16 @@ var path = require('path');
 var log = require('npmlog');
 var cp = require('child_process');
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
 var path = require('path');
 
 function testbinary(gyp, argv, callback) {
     var args = [];
     var options = {};
     var shell_cmd = process.execPath;
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
-    var opts = versioning.evaluate(package_json, gyp.opts);
+    var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
+    var opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
     // skip validation for runtimes we don't explicitly support (like electron)
     if (opts.runtime &&
         opts.runtime !== 'node-webkit' &&

lib/testpackage.js

@@ -9,13 +9,15 @@ var path = require('path');
 var log = require('npmlog');
 var existsAsync = fs.exists || path.exists;
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
 var testbinary = require('./testbinary.js');
 var tar = require('tar');
 var mkdirp = require('mkdirp');
 
 function testpackage(gyp, argv, callback) {
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
-    var opts = versioning.evaluate(package_json, gyp.opts);
+    var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
+    var opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
     var tarball = opts.staged_tarball;
     existsAsync(tarball, function(found) {
         if (!found) {

lib/unpublish.js

@@ -7,14 +7,16 @@ exports.usage = 'Unpublishes pre-built binary (requires aws-sdk)';
 var fs = require('fs');
 var log = require('npmlog');
 var versioning = require('./util/versioning.js');
+var napi = require('./util/napi.js');
 var s3_setup = require('./util/s3_setup.js');
 var url = require('url');
 var config = require('rc')("node_pre_gyp",{acl:"public-read"});
 
 function unpublish(gyp, argv, callback) {
     var AWS = require("aws-sdk");
     var package_json = JSON.parse(fs.readFileSync('./package.json'));
-    var opts = versioning.evaluate(package_json, gyp.opts);
+    var napi_build_version = napi.get_napi_build_version_from_command_args(argv);
+    var opts = versioning.evaluate(package_json, gyp.opts, napi_build_version);
     s3_setup.detect(opts.hosted_path,config);
     AWS.config.update(config);
     var key_name = url.resolve(config.prefix,opts.package_name);