Progress and a tiny WASM binary parser

Author: dcodeIO

README.md

@@ -23,6 +23,9 @@ A few early examples to get an idea:
 * **[PSON decoder](./examples/pson)**<br />
   A simple decoder for the PSON binary format.
 
+* **[WASM parser](./lib/parse)**<br />
+  A WebAssembly binary parser in WebAssembly.
+
 Or browse the [compiler tests](./tests/compiler) for a more in-depth overview of what's supported already. One of them is a [showcase](./tests/compiler/showcase.ts).
 
 Installation

bin/asc.js

@@ -93,7 +93,7 @@ exports.compileString = (source, extraArgs={}) => new Promise((resolve, reject)
     const libDir = path.join(__dirname, "../std", "assembly");
     const libFiles = require("glob").sync("**/*.ts", { cwd: libDir });
     libFiles.forEach(file =>
-      exports.libraryFiles["~lib/" + file.replace(/\.ts$/, "")] = readFileNode(path.join(libDir, file), { encoding: "utf8" })
+      exports.libraryFiles[file.replace(/\.ts$/, "")] = readFileNode(path.join(libDir, file), { encoding: "utf8" })
     );
   }
 
@@ -249,54 +249,71 @@ exports.main = function main(argv, options, callback) {
 
       // Load library file if explicitly requested
       if (sourcePath.startsWith(exports.libraryPrefix)) {
-        for (let i = 0, k = libDirs.length; i < k; ++i) {
-          if (exports.libraryFiles.hasOwnProperty(sourcePath)) {
-            sourceText = exports.libraryFiles[sourcePath];
-            sourcePath += ".ts";
-          } else {
-            sourceText = readFile(path.join(
-              libDirs[i],
-              sourcePath.substring(exports.libraryPrefix.length) + ".ts")
-            );
+        const plainName = sourcePath.substring(exports.libraryPrefix.length);
+        const indexName = sourcePath.substring(exports.libraryPrefix.length) + "/index";
+        if (exports.libraryFiles.hasOwnProperty(plainName)) {
+          sourceText = exports.libraryFiles[plainName];
+          sourcePath = exports.libraryPrefix + plainName + ".ts";
+        } else if (exports.libraryFiles.hasOwnProperty(indexName)) {
+          sourceText = exports.libraryFiles[indexName];
+          sourcePath = exports.libraryPrefix + indexName + ".ts";
+        } else {
+          for (let i = 0, k = libDirs.length; i < k; ++i) {
+            const dir = libDirs[i];
+            sourceText = readFile(path.join(dir, plainName + ".ts"));
             if (sourceText !== null) {
-              sourcePath += ".ts";
+              sourcePath = exports.libraryPrefix + plainName + ".ts";
               break;
+            } else {
+              sourceText = readFile(path.join(dir, indexName + ".ts"));
+              if (sourceText !== null) {
+                sourcePath = exports.libraryPrefix + indexName + ".ts";
+                break;
+              }
             }
           }
         }
 
-      // Otherwise try nextFile.ts, nextFile/index.ts, ~lib/nextFile.ts
+      // Otherwise try nextFile.ts, nextFile/index.ts, ~lib/nextFile.ts, ~lib/nextFile/index.ts
       } else {
-        sourceText = readFile(path.join(baseDir, sourcePath + ".ts"));
+        const plainName = sourcePath;
+        const indexName = sourcePath + "/index";
+        sourceText = readFile(path.join(baseDir, plainName + ".ts"));
         if (sourceText !== null) {
-          sourcePath += ".ts";
+          sourcePath = plainName + ".ts";
         } else {
-          sourceText = readFile(path.join(baseDir, sourcePath, "index.ts"));
+          sourceText = readFile(path.join(baseDir, indexName + ".ts"));
           if (sourceText !== null) {
-            sourcePath += "/index.ts";
-          } else {
-            const key = exports.libraryPrefix + sourcePath;
-            if (exports.libraryFiles.hasOwnProperty(key)) {
-              sourceText = exports.libraryFiles[key];
-              sourcePath = key + ".ts";
+            sourcePath = indexName + ".ts";
+          } else if (!plainName.startsWith(".")) {
+            if (exports.libraryFiles.hasOwnProperty(plainName)) {
+              sourceText = exports.libraryFiles[plainName];
+              sourcePath = exports.libraryPrefix + plainName + ".ts";
+            } else if (exports.libraryFiles.hasOwnProperty(indexName)) {
+              sourceText = exports.libraryFiles[indexName];
+              sourcePath = exports.libraryPrefix + indexName + ".ts";
             } else {
               for (let i = 0, k = libDirs.length; i < k; ++i) {
                 const dir = libDirs[i];
-                sourceText = readFile(path.join(dir, sourcePath + ".ts"));
+                sourceText = readFile(path.join(dir, plainName + ".ts"));
                 if (sourceText !== null) {
-                  sourcePath = exports.libraryPrefix + sourcePath + ".ts";
+                  sourcePath = exports.libraryPrefix + plainName + ".ts";
                   break;
+                } else {
+                  sourceText = readFile(path.join(dir, indexName + ".ts"));
+                  if (sourceText !== null) {
+                    sourcePath = exports.libraryPrefix + indexName + ".ts";
+                    break;
+                  }
                 }
               }
-              if (sourceText === null) {
-                return callback(
-                  Error("Import file '" + sourcePath + ".ts' not found.")
-                );
-              }
             }
           }
         }
       }
+      if (sourceText == null) {
+        return callback(Error("Import file '" + plainName + ".ts' not found."));
+      }
       stats.parseCount++;
       stats.parseTime += measure(() => {
         assemblyscript.parseFile(sourceText, sourcePath, false, parser);

dist/asc.js

@@ -12,10 +12,6 @@
         ["boolean", "Use `bool` instead."]
       ]
     },
-    "object-literal-shorthand": {
-      "severity": "error",
-      "options": ["never"]
-    },
     "restrict-plus-operands": {
       "severity": "error"
     },

dist/asc.js.map

@@ -0,0 +1,95 @@
+# ![AS](https://avatars1.githubusercontent.com/u/28916798?s=48) parse
+
+A WebAssembly binary parser in WebAssembly.
+
+API
+---
+
+* **parse**(binary: `Uint8Array`, options?: `ParseOptions`): `void`<br />
+  Parses the contents of a WebAssembly binary according to the specified options.
+
+* **ParseOptions**<br />
+  Options specified to the parser. The `onSection` callback determines the sections being evaluated in detail.
+
+  * **onSection**?(id: `SectionId`, payloadOff: `number`, payloadLen: `number`, nameOff: `number`, nameLen: `number`): `boolean`<br />
+    Called with each section in the binary. Returning `true` evaluates the section.
+
+  * **onType**?(index: `number`, form: `number`): `void`<br />
+    Called with each function type if the type section is evaluated.
+
+  * **onTypeParam**?(index: `number`, paramIndex: `number`, paramType: `Type`): `void`<br />
+    Called with each function parameter if the type section is evaluated.
+
+  * **onTypeReturn**?(index: `number`, returnIndex: `number`, returnType: `Type`): `void`<br />
+    Called with each function return type if the type section is evaluated.
+
+  * **onImport**?(index: `number`, kind: `ExternalKind`, moduleOff: `number`, moduleLen: `number`, fieldOff: `number`, fieldLen: `number`): `void`<br />
+    Called with each import if the import section is evaluated.
+
+  * **onFunctionImport**?(index: `number`, type: `number`): `void`<br />
+    Called with each function import if the import section is evaluated.
+
+  * **onTableImport**?(index: `number`, type: `Type`, initial: `number`, maximum: `number`, flags: `number`): `void`<br />
+    Called with each table import if the import section is evaluated.
+
+  * **onMemoryImport**?(index: `number`, initial: `number`, maximum: `number`, flags: `number`): `void`<br />
+    Called with each memory import if the import section is evaluated.
+
+  * **onGlobalImport**?(index: `number`, type: `Type`, mutability: `number`): `void`<br />
+    Called with each global import if the import section is evaluated.
+
+  * **onMemory**?(index: `number`, initial: `number`, maximum: `number`, flags: `number`): `void`<br />
+    Called with each memory if the memory section is evaluated.
+
+  * **onFunction**?(index: `number`, typeIndex: `number`): `void`<br />
+    Called with each function if the function section is evaluated.
+
+  * **onGlobal**?(index: `number`, type: `Type`, mutability: `number`): `void`<br />
+    Called with each global if the global section is evaluated.
+
+  * **onStart**?(index: `number`): `void`<br />
+    Called with the start function index if the start section is evaluated.
+
+  * **onExport**?(index: `number`, kind: `ExternalKind`, kindIndex: `number`, nameOff: `number`, nameLen: `number`): `void`<br />
+    Called with each export if the export section is evaluated.
+
+* **Type**<br />
+  A value or element type, depending on context.
+
+  | Name    | Value
+  |---------|-------
+  | i32     | 0x7f
+  | i64     | 0x7e
+  | f32     | 0x7d
+  | f64     | 0x7c
+  | anyfunc | 0x70
+  | func    | 0x60
+  | none    | 0x40
+
+* **SectionId**<br />
+  Numerical id of the current section.
+
+  | Name     | Value
+  |----------|-------
+  | Custom   | 0
+  | Type     | 1
+  | Import   | 2
+  | Function | 3
+  | Table    | 4
+  | Memory   | 5
+  | Global   | 6
+  | Export   | 7
+  | Start    | 8
+  | Element  | 9
+  | Code     | 10
+  | Data     | 11
+
+* **ExternalKind**<br />
+  Kind of an export or import.
+
+  | Name     | Value
+  |----------|-------
+  | Function | 0
+  | Table    | 1
+  | Memory   | 2
+  | Global   | 3