init

erlccache

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+#!/usr/bin/env node
+/*
+  erlccache — (c) 2010 Jan Lehnardt <jan@apache.org>
+  use instead of erlc and your builds will magically speed up
+  somebody needs to turn this into proper node code, or sh or whatever
+  MIT License
+*/
+
+// CUSTOMIZE HERE
+var erlc = "/Users/jan/.local/bin/erlc";
+var dir = "/Users/jan/.erlccache/";
+// STOP CUSTOMIZING
+
+
+var sys = require("sys");
+var child_process = require("child_process");
+var crypto = require("crypto");
+var fs = require("fs");
+
+
+var args = process.argv.slice(2).toString();
+var cmd = erlc + " " + args;
+
+// execute a shell command
+function exec(cmd, fun) {
+  fun = fun || function (error, stdout, stderr) {
+    sys.print("stdout: " + stdout);
+    sys.print("stderr: " + stderr);
+    if (error !== null) {
+      sys.puts("exec error: " + error);
+    }
+  };
+  child_process.exec(cmd, fun);
+}
+
+// get the .erl file out of cmd
+function erl_parse_file(cmd) {
+  var file = cmd.match(/[\w]+\.erl\s*/).toString();
+  return file;
+}
+
+// find location of .beam file given the cmd
+function erl_beamfile(cmd) {
+  return process.cwd() + "/" + erl_parse_file(cmd).replace(/.erl/, ".beam");
+}
+
+// create a sha1 hex digest from the cmd .erl file
+function cache_hash(cmd) {
+  var hash = crypto.createHash("sha1");
+  var file = erl_parse_file(cmd);
+  hash.update(fs.readFileSync(file, "binary"));
+  return hash.digest("hex");
+}
+
+// copy(from, to); -- synchronous
+function cache_file_copy(from, to) {
+  fs.writeFileSync(to, fs.readFileSync(from, "binary"), "binary");
+  
+}
+
+// see if the filename in cmd is cached, if not compile and cache
+function cache_hit(cmd) {
+  // make cache dir if it doesn't exist
+  try {
+    fs.statSync(dir);
+  } catch(e) {
+    fs.mkdirSync(dir, 0700);
+  }
+
+  // hash cmd
+  var hash = cache_hash(cmd);
+  try {
+    fs.statSync(dir + hash);
+  } catch(e) {
+    // compile
+    exec(cmd, function(error, stdout, stderr) {
+      if(!error) {
+        var beamfile = erl_beamfile(cmd);
+        // add beam file to dir + hash(cmd)
+        cache_file_copy(beamfile, dir + hash);
+      }
+    });
+    return false;
+  }
+  return true
+}
+
+// copy the cached beamfile to the final destination as if erlc did it
+function cache_copy(cmd) {
+  var beamfile = erl_beamfile(cmd);
+  var cachefile = dir + cache_hash(cmd);
+  cache_file_copy(cachefile, beamfile);
+}
+
+if(cache_hit(cmd)) {
+  cache_copy(cmd);
+}
+
+//done