Generate source maps

Allow the precompiler to generate source maps when the srcFile parameter is passed.

This refactors large chunks of the code generation pipeline, allowing metadata to be associated with code chunks as well as breaking out much of the code generation logic into a separate helper.

1 files changed, 151 insertions, 0 deletions

diff --git a/lib/handlebars/compiler/code-gen.js b/lib/handlebars/compiler/code-gen.js
new file mode 100644
index 0000000..7d1b4ca
--- /dev/null
+++ b/lib/handlebars/compiler/code-gen.js
@@ -0,0 +1,151 @@
+import {isArray} from "../utils";
+
+try {
+  var SourceMap = require('source-map'),
+        SourceNode = SourceMap.SourceNode;
+} catch (err) {
+  /* istanbul ignore next: tested but not covered in istanbul due to dist build  */
+  SourceNode = function(line, column, srcFile, chunks) {
+    this.src = '';
+    if (chunks) {
+      this.add(chunks);
+    }
+  };
+  /* istanbul ignore next */
+  SourceNode.prototype = {
+    add: function(chunks) {
+      if (isArray(chunks)) {
+        chunks = chunks.join('');
+      }
+      this.src += chunks;
+    },
+    prepend: function(chunks) {
+      if (isArray(chunks)) {
+        chunks = chunks.join('');
+      }
+      this.src = chunks + this.src;
+    },
+    toStringWithSourceMap: function() {
+      return {code: this.toString()};
+    },
+    toString: function() {
+      return this.src;
+    }
+  };
+}
+
+
+function castChunk(chunk, codeGen, loc) {
+  if (isArray(chunk)) {
+    var ret = [];
+
+    for (var i = 0, len = chunk.length; i < len; i++) {
+      ret.push(codeGen.wrap(chunk[i], loc));
+    }
+    return ret;
+  } else if (typeof chunk === 'boolean' || typeof chunk === 'number') {
+    // Handle primitives that the SourceNode will throw up on
+    return chunk+'';
+  }
+  return chunk;
+}
+
+
+function CodeGen(srcFile) {
+  this.srcFile = srcFile;
+  this.source = [];
+}
+
+CodeGen.prototype = {
+  prepend: function(source, loc) {
+    this.source.unshift(this.wrap(source, loc));
+  },
+  push: function(source, loc) {
+    this.source.push(this.wrap(source, loc));
+  },
+
+  merge: function() {
+    var source = this.empty();
+    this.each(function(line) {
+      source.add(['  ', line, '\n']);
+    });
+    return source;
+  },
+
+  each: function(iter) {
+    for (var i = 0, len = this.source.length; i < len; i++) {
+      iter(this.source[i]);
+    }
+  },
+
+  empty: function(loc) {
+    loc = loc || this.currentLocation || {};
+    return new SourceNode(loc.firstLine, loc.firstColumn, this.srcFile);
+  },
+  wrap: function(chunk, loc) {
+    if (chunk instanceof SourceNode) {
+      return chunk;
+    }
+
+    loc = loc || this.currentLocation || {};
+    chunk = castChunk(chunk, this, loc);
+
+    return new SourceNode(loc.firstLine, loc.firstColumn, this.srcFile, chunk);
+  },
+
+  functionCall: function(fn, type, params) {
+    params = this.generateList(params);
+    return this.wrap([fn, type ? '.' + type + '(' : '(', params, ')']);
+  },
+
+  quotedString: function(str) {
+    return '"' + str
+      .replace(/\\/g, '\\\\')
+      .replace(/"/g, '\\"')
+      .replace(/\n/g, '\\n')
+      .replace(/\r/g, '\\r')
+      .replace(/\u2028/g, '\\u2028')   // Per Ecma-262 7.3 + 7.8.4
+      .replace(/\u2029/g, '\\u2029') + '"';
+  },
+
+  objectLiteral: function(obj) {
+    var pairs = [];
+
+    for (var key in obj) {
+      if (obj.hasOwnProperty(key)) {
+        pairs.push([this.quotedString(key), ':', castChunk(obj[key], this)]);
+      }
+    }
+
+    var ret = this.generateList(pairs);
+    ret.prepend('{');
+    ret.add('}');
+    return ret;
+  },
+
+
+  generateList: function(entries, loc) {
+    var ret = this.empty(loc);
+
+    for (var i = 0, len = entries.length; i < len; i++) {
+      if (i) {
+        ret.add(',');
+      }
+
+      ret.add(castChunk(entries[i], this, loc));
+    }
+
+    return ret;
+  },
+
+  generateArray: function(entries, loc) {
+    var ret = this.generateList(entries, loc);
+    ret.prepend('[');
+    ret.add(']');
+
+    return ret;
+  }
+};
+
+export default CodeGen;
+