Move builder/preprocessor into its own file.

external/builder/builder.js

@@ -0,0 +1,142 @@
+require('../shelljs/make');
+var fs = require('fs'),
+    path = require('path'),
+    vm = require('vm');
+
+/**
+ * A simple preprocessor that is based on the firefox preprocessor
+ * see (https://developer.mozilla.org/en/Build/Text_Preprocessor).  The main
+ * difference is that this supports a subset of the commands and it supports
+ * preproccesor commands in html style comments.
+ * Currently Supported commands:
+ * - if
+ * - else
+ * - endif
+ * - include
+ * - expand
+ */
+function preprocess(inFilename, outFilename, defines) {
+  // TODO make this really read line by line.
+  var lines = fs.readFileSync(inFilename).toString().split('\n');
+  var totalLines = lines.length;
+  var out = '';
+  var i = 0;
+  function readLine() {
+    if (i < totalLines) {
+      return lines[i++];
+    }
+    return null;
+  }
+  var writeLine = typeof outFilename === 'function' ? outFilename : function(line) {
+    out += line + '\n';
+  }
+  function include(file) {
+    var realPath = fs.realpathSync(inFilename);
+    var dir = path.dirname(realPath);
+    preprocess(path.join(dir, file), writeLine, defines);
+  }
+  function expand(line) {
+    line = line.replace(/__[\w]+__/g, function(variable) {
+      variable = variable.substring(2, variable.length - 2);
+      if (variable in defines) {
+        return defines[variable];
+      }
+      return '';
+    });
+    writeLine(line);
+  }
+
+  var s, state = 0, stack = [];
+  var control = /^(?:\/\/|<!--)\s*#(if|else|endif|expand|include)(?:\s+(.*?)(?:-->)?$)?/;
+  var lineNumber = 0;
+  while ((s = readLine()) !== null) {
+    ++lineNumber;
+    var m = control.exec(s);
+    if (m) {
+      switch (m[1]) {
+        case 'if':
+          stack.push(state);
+          try {
+            state = vm.runInNewContext(m[2], defines) ? 3 : 1;
+          } catch (e) {
+            console.error('Could not evalute line \'' + m[2] + '\' at ' +
+                          fs.realpathSync(inFilename) + ':' + lineNumber);
+            throw e;
+          }
+          break;
+        case 'else':
+          state = state === 1 ? 3 : 2;
+          break;
+        case 'endif':
+          state = stack.pop();
+          break;
+        case 'expand':
+          if (state === 0 || state === 3)
+            expand(m[2]);
+          break;
+        case 'include':
+          if (state === 0 || state === 3)
+            include(m[2]);
+          break;
+      }
+    } else {
+      if (state === 0) {
+        writeLine(s);
+      } else if(state === 3) {
+        writeLine(s.replace(/^\/\/|^<!--|-->/g, "  "));
+      }
+    }
+  }
+  if (state !== 0 || stack.length !== 0)
+    throw new Error('Missing endif in preprocessor.');
+  if (typeof outFilename !== 'function')
+    fs.writeFileSync(outFilename, out);
+}
+exports.preprocess = preprocess;
+
+/**
+ * Simplifies common build steps.
+ * @param setup
+ *        .defines defines for preprocessors
+ *        .copy array of arrays of source and destination pairs of files to copy
+ *        .preprocess array of arrays of source and destination pairs of files
+ *                    run through preprocessor
+ */
+function build(setup) {
+  var defines = setup.defines;
+
+  setup.copy.forEach(function(option) {
+    var source = option[0];
+    var destination = option[1];
+    cp('-R', source, destination);
+  });
+
+  setup.preprocess.forEach(function(option) {
+    var sources = option[0];
+    var destination = option[1];
+
+    sources = ls('-R', sources);
+    sources.forEach(function(source) {
+      // ??? Warn if the source is wildcard and dest is file?
+      var destWithFolder = destination;
+      if (test('-d', destination))
+        destWithFolder += '/' + path.basename(source);
+      preprocess(source, destWithFolder, defines);
+    });
+  });
+}
+exports.build = build;
+
+/**
+ * Merge two defines arrays. Values in the second param will override values in
+ * the first.
+ */
+function merge(defaults, defines) {
+  var ret = {};
+  for (var key in defaults)
+    ret[key] = defaults[key];
+  for (key in defines)
+    ret[key] = defines[key];
+  return ret;
+}
+exports.merge = merge;