Add proper tests, exception handling, implement getAbstractName

src/runtime/javascript/index.ts

@@ -1,44 +1,122 @@
+import errno from './errno'
+import ffi from 'ffi'
 import { deref } from 'ref'
-import * as ref from 'ref'
-import * as ffi from 'ffi'
+import ref from 'ref'
+import Struct from 'ref-struct'
+
+// ----------------------------------------------------------------------------
+// FFI "Types"
 
 const PgfDB = ref.types.int
 const PgfDBPtr = ref.refType(PgfDB)
 const PgfRevision = ref.types.int
 const PgfRevisionPtr = ref.refType(PgfRevision)
-const PgfExn = ref.types.int
-const PgfExnPtr = ref.refType(PgfExn)
-// const stringPtr = ref.refType(ref.types.CString)
-
-const PGF = ffi.Library('libpgf', {
-  'pgf_read_pgf': [ PgfDBPtr, [ 'string', PgfRevisionPtr, PgfExnPtr ] ],
-  'pgf_write_pgf': [ 'void', [ 'string', PgfDBPtr, PgfRevisionPtr, PgfExnPtr ] ],
+const PgfExn = Struct({
+  type: ref.types.int,
+  code: ref.types.int,
+  msg: ref.types.CString
 })
+const PgfExnPtr = ref.refType(PgfExn)
+const PgfText = Struct({
+  size: ref.types.size_t,
+  text: ref.types.char // char[]
+})
+const PgfTextPtr = ref.refType(PgfText)
+
+// ----------------------------------------------------------------------------
+// TypeScript Types
 
 interface Pointer extends Buffer {
   deref(): any
 }
 
-interface State {
-  db: Pointer,
-  revision: number
-}
-const state: State = {
-  db: ref.NULL_POINTER as Pointer,
-  revision: 0
-}
-
-export default {
-  readPGF: function (path: string) {
-    const rev = ref.alloc(PgfRevision) as Pointer
-    const err = ref.alloc(PgfExn) as Pointer
-    const db = PGF.pgf_read_pgf(path, rev, err)
-    if (err.deref() === 0) {
-      state.db = db
-      state.revision = rev.deref()
-      console.log(`ok`)
-    } else {
-      console.error(`error ${err.deref()}`)
-    }
+class PGFError extends Error {
+  constructor(message: string) {
+    super(message)
   }
 }
+
+// ----------------------------------------------------------------------------
+// FFI
+
+const runtime = ffi.Library('libpgf', {
+  'pgf_read_pgf': [ PgfDBPtr, [ ref.types.CString, PgfRevisionPtr, PgfExnPtr ] ],
+  'pgf_write_pgf': [ ref.types.void, [ ref.types.CString, PgfDBPtr, PgfRevisionPtr, PgfExnPtr ] ],
+  'pgf_abstract_name': [ PgfTextPtr, [ PgfDBPtr, PgfRevision, PgfExnPtr ] ],
+})
+
+// ----------------------------------------------------------------------------
+// Helpers
+
+function handleError (errPtr: Pointer): void {
+  const err = errPtr.deref()
+  switch (err.type) {
+    // PGF_EXN_NONE
+    case 0: return
+
+    // PGF_EXN_SYSTEM_ERROR
+    case 1:
+      const desc = errno.lookup(err.code)
+      throw new Error(`${desc}: ${err.msg}`)
+
+    // PGF_EXN_PGF_ERROR
+    case 2:
+      throw new PGFError(err.msg)
+
+    // PGF_EXN_OTHER_ERROR
+    case 3:
+      throw new Error(err.msg)
+
+    default:
+      throw new Error(`unknown error type: ${err.type}`)
+  }
+}
+
+function PgfText_AsString (txtPtr: Pointer) {
+  const txtSize = txtPtr.deref().size
+  const charPtr = ref.reinterpret(txtPtr, txtSize, ref.types.size_t.size)
+  return charPtr.toString('utf8')
+}
+
+// ----------------------------------------------------------------------------
+// PGF grammar object
+
+class PGF {
+  db: Pointer
+  revision: number
+
+  constructor () {
+    this.db = ref.NULL_POINTER as Pointer
+    this.revision = 0
+  }
+
+  getAbstractName () {
+    const err = ref.alloc(PgfExn) as Pointer
+    const txt = runtime.pgf_abstract_name(this.db, this.revision, err)
+    handleError(err)
+    return PgfText_AsString(txt)
+  }
+
+}
+
+// ----------------------------------------------------------------------------
+// PGF module functions
+
+function readPGF (path: string): PGF {
+  const rev = ref.alloc(PgfRevision) as Pointer
+  const err = ref.alloc(PgfExn) as Pointer
+  const db = runtime.pgf_read_pgf(path, rev, err)
+  handleError(err)
+
+  const state = new PGF()
+  state.db = db
+  state.revision = rev.deref()
+  return state
+}
+
+// ----------------------------------------------------------------------------
+// Exposed library API
+
+export default {
+  readPGF
+}