Do the dependency dance.

lib/install.js

@@ -11,7 +11,8 @@ var npm = require("../npm"),
   fetch = require("./utils/fetch"),
   sys = require("sys"),
   fs = require("fs"),
-  path = require("path");
+  path = require("path"),
+  semver = require("./utils/semver");
 
 module.exports = install;
 
@@ -45,7 +46,7 @@ function install (tarball, cb) {
   // at this point, presumably the filesystem knows how to open it.
   chain(
     [fs, "stat", tarball],
-    [ensureDir, unpackTargetDir, 0755],
+    [ensureDir, unpackTargetDir],
     [unpackTar, tarball, unpackTargetDir],
     // clean up
     [function (cb) { log("unpacked, deleting"); cb() }],
@@ -62,7 +63,16 @@ function install (tarball, cb) {
     }],
 
     // move to ROOT/.npm/{name}/{version}/package
+    [function (cb) { log("about to move into place"); cb() }],
     [moveIntoPlace, unpackTargetDir, pkg],
+
+    [function (cb) { log("about to resolve deps"); cb() }],
+    // link deps into ROOT/.npm/{name}/{version}/dependencies
+    // this is then added to require.paths, but ONLY for this package's main module.
+    // of course, they could do require(".npm/foo/1.0.3/dependencies/bar") to import
+    // whichever version of bar is currently satisfying foo-1.0.3's need.
+    // For now, all dependencies must already be installed, or the install fails.
+    [resolveDependencies, pkg],
 
     // generate ROOT/.npm/{name}/{version}/main.js
     [createMain, pkg],
@@ -86,6 +96,79 @@ function install (tarball, cb) {
   );
 };
 
+// make sure that all the dependencies have been installed.
+// todo: if they're not, then install them, and come back here.
+function resolveDependencies (pkg, topCb) {
+  log("Resolving dependencies");
+  pkg = pkg && pkg.data;
+  if (!pkg) return cb(new Error("Package not found to resolve dependencies"));
+  // link foo-1.0.3 to ROOT/.npm/{pkg}/{ver}/dependencies/foo
+
+  var found = [];
+  chain(
+    [ensureDir, path.join(npm.dir, pkg.name, pkg.version, "dependencies")],
+    [function (cb) {
+      if (!pkg.dependencies) return topCb();
+      // don't create anything until they're all verified.
+      var reqs = [];
+      for (var i in pkg.dependencies) reqs.push({name:i, ver:pkg.dependencies[i]});
+      if (!reqs.length) return topCb();
+
+      (function R (req) {
+        if (!req) return cb();
+        log(req.name+" "+req.ver, "required");
+        // see if we have this thing installed.
+        fs.readdir(path.join(npm.dir, req.name), function (er, versions) {
+          if (er) return cb(new Error(
+            "Required package: "+req.name+"("+req.ver+") not found."));
+          // TODO: Get the "stable" version if there is one.
+          // Look that up from the registry.
+          versions.sort(semver.compare);
+          var i = versions.length;
+          while (i--) {
+            if (semver.satisfies(versions[i], req.ver)) {
+              found.push({name:req.name, ver:versions[i]});
+              return R(reqs.pop());
+            }
+          }
+          return cb(new Error(
+            "Required package: "+req.name+"("+req.ver+") not found. "+
+            "(Found: "+JSON.stringify(versions)+")"));
+        });
+      })(reqs.pop());
+    }],
+    [function (cb) {
+      // link in all the found reqs.
+      (function L (req) {
+        if (!req) return cb();
+
+        log(req.name+ "-" +req.ver, "found");
+
+        // link ROOT/.npm/{pkg}/{ver}/dependencies/{req.name} to
+        // ROOT/{req.name}-{req.version}
+        // both the JS and the folder, if they're there
+        // then try again with the next req.
+        var to = path.join(npm.dir, pkg.name, pkg.version, "dependencies", req.name),
+          from = path.join(npm.root, req.name + "-" + req.ver);
+        function link (cb) {
+          fs.stat(from, function (er, stat) {
+            if (er) return cb();
+            processCb("ln", ["-s", from, to], cb);
+          });
+        };
+
+        // todo: link to pkg.linkdeps[ req.name ], too
+        chain([link], [function (cb) {
+          from += ".js";
+          to += ".js";
+          cb();
+        }], [link], function (er) { if (er) return topCb(er); L(found.pop()) });
+      })(found.pop());
+    }],
+    topCb
+  );
+}
+
 // move to ROOT/.npm/{name}/{version}/package
 function moveIntoPlace (dir, pkg, cb) {
   pkg = pkg.data;
@@ -97,13 +180,13 @@ function moveIntoPlace (dir, pkg, cb) {
   chain(
     [function (cb) {
       path.exists(target, function (e) {
-        log(target + " " + (e?"exists, removing it":"doesn't exist, creating it"));
+        log(target + " ", (e?"remove":"creating"));
         if (e) rm(target, function (er, ok) {
           if (er) {
-            log("couldn't remove "+target);
+            log(target, "could not remove!");
             cb(new Error(target+" exists, and can't be removed"));
           } else {
-            log(target+" successfully unlinked");
+            log(target,"unlinked");
             cb();
           };
         });
@@ -120,7 +203,7 @@ function moveIntoPlace (dir, pkg, cb) {
 
 function fetchAndInstall (tarball, cb) {
   log("fetchAndInstall: "+tarball);
-  ensureDir(npm.tmp, 0755, function (er, ok) {
+  ensureDir(npm.tmp, function (er, ok) {
     if (er) return cb(er, ok);
     var target = path.join(npm.tmp, tarball.replace(/[^a-zA-Z0-9]/g, "-")+"-"+
                            Date.now()+"-"+Math.random()+".tgz");
@@ -141,7 +224,7 @@ function ensureDir (ensure, chmod, cb) {
     cb = chmod;
     chmod = 0755;
   }
-  log("Ensuring: "+ensure);
+  log(ensure, "mkdir");
   walker.push(dirs.shift()); // gobble the "/" first
   (function S (d) {
     if (d === undefined) return cb();
@@ -200,9 +283,14 @@ function createMain (pkg,cb) {
 
   var code =
       "// generated by npm, please don't touch!\n"+
-      "module.exports=require("+
+      "require.paths.unshift("+
+        JSON.stringify(path.join(npm.dir, pkg.name, pkg.version, "dependencies"))+
+      ");"+
+      "module.exports = require("+
         JSON.stringify(path.join(npm.dir, pkg.name, pkg.version, "package", pkg.main)) +
-      ");\n",
+      ");"+
+      "require.paths.shift();"+
+      "\n",
     proxyFile = path.join(npm.dir, pkg.name, pkg.version, "main.js");
 
   fs.writeFile(proxyFile, code, "ascii", cb);