1 files changed, 223 insertions, 0 deletions
diff --git a/cli/rt/20_blob.js b/cli/rt/20_blob.js
new file mode 100644
index 000000000..5b0ef349e
--- /dev/null
+++ b/cli/rt/20_blob.js
@@ -0,0 +1,223 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+((window) => {
+  const { build } = window.__bootstrap.build;
+  const { ReadableStream } = window.__bootstrap.streams;
+
+  const bytesSymbol = Symbol("bytes");
+
+  function containsOnlyASCII(str) {
+    if (typeof str !== "string") {
+      return false;
+    }
+    return /^[\x00-\x7F]*$/.test(str);
+  }
+
+  function convertLineEndingsToNative(s) {
+    const nativeLineEnd = build.os == "windows" ? "\r\n" : "\n";
+
+    let position = 0;
+
+    let collectionResult = collectSequenceNotCRLF(s, position);
+
+    let token = collectionResult.collected;
+    position = collectionResult.newPosition;
+
+    let result = token;
+
+    while (position < s.length) {
+      const c = s.charAt(position);
+      if (c == "\r") {
+        result += nativeLineEnd;
+        position++;
+        if (position < s.length && s.charAt(position) == "\n") {
+          position++;
+        }
+      } else if (c == "\n") {
+        position++;
+        result += nativeLineEnd;
+      }
+
+      collectionResult = collectSequenceNotCRLF(s, position);
+
+      token = collectionResult.collected;
+      position = collectionResult.newPosition;
+
+      result += token;
+    }
+
+    return result;
+  }
+
+  function collectSequenceNotCRLF(
+    s,
+    position,
+  ) {
+    const start = position;
+    for (
+      let c = s.charAt(position);
+      position < s.length && !(c == "\r" || c == "\n");
+      c = s.charAt(++position)
+    );
+    return { collected: s.slice(start, position), newPosition: position };
+  }
+
+  function toUint8Arrays(
+    blobParts,
+    doNormalizeLineEndingsToNative,
+  ) {
+    const ret = [];
+    const enc = new TextEncoder();
+    for (const element of blobParts) {
+      if (typeof element === "string") {
+        let str = element;
+        if (doNormalizeLineEndingsToNative) {
+          str = convertLineEndingsToNative(element);
+        }
+        ret.push(enc.encode(str));
+        // eslint-disable-next-line @typescript-eslint/no-use-before-define
+      } else if (element instanceof Blob) {
+        ret.push(element[bytesSymbol]);
+      } else if (element instanceof Uint8Array) {
+        ret.push(element);
+      } else if (element instanceof Uint16Array) {
+        const uint8 = new Uint8Array(element.buffer);
+        ret.push(uint8);
+      } else if (element instanceof Uint32Array) {
+        const uint8 = new Uint8Array(element.buffer);
+        ret.push(uint8);
+      } else if (ArrayBuffer.isView(element)) {
+        // Convert view to Uint8Array.
+        const uint8 = new Uint8Array(element.buffer);
+        ret.push(uint8);
+      } else if (element instanceof ArrayBuffer) {
+        // Create a new Uint8Array view for the given ArrayBuffer.
+        const uint8 = new Uint8Array(element);
+        ret.push(uint8);
+      } else {
+        ret.push(enc.encode(String(element)));
+      }
+    }
+    return ret;
+  }
+
+  function processBlobParts(
+    blobParts,
+    options,
+  ) {
+    const normalizeLineEndingsToNative = options.ending === "native";
+    // ArrayBuffer.transfer is not yet implemented in V8, so we just have to
+    // pre compute size of the array buffer and do some sort of static allocation
+    // instead of dynamic allocation.
+    const uint8Arrays = toUint8Arrays(blobParts, normalizeLineEndingsToNative);
+    const byteLength = uint8Arrays
+      .map((u8) => u8.byteLength)
+      .reduce((a, b) => a + b, 0);
+    const ab = new ArrayBuffer(byteLength);
+    const bytes = new Uint8Array(ab);
+    let courser = 0;
+    for (const u8 of uint8Arrays) {
+      bytes.set(u8, courser);
+      courser += u8.byteLength;
+    }
+
+    return bytes;
+  }
+
+  function getStream(blobBytes) {
+    // TODO: Align to spec https://fetch.spec.whatwg.org/#concept-construct-readablestream
+    return new ReadableStream({
+      type: "bytes",
+      start: (controller) => {
+        controller.enqueue(blobBytes);
+        controller.close();
+      },
+    });
+  }
+
+  async function readBytes(
+    reader,
+  ) {
+    const chunks = [];
+    while (true) {
+      const { done, value } = await reader.read();
+      if (!done && value instanceof Uint8Array) {
+        chunks.push(value);
+      } else if (done) {
+        const size = chunks.reduce((p, i) => p + i.byteLength, 0);
+        const bytes = new Uint8Array(size);
+        let offs = 0;
+        for (const chunk of chunks) {
+          bytes.set(chunk, offs);
+          offs += chunk.byteLength;
+        }
+        return bytes;
+      } else {
+        throw new TypeError("Invalid reader result.");
+      }
+    }
+  }
+
+  // A WeakMap holding blob to byte array mapping.
+  // Ensures it does not impact garbage collection.
+  const blobBytesWeakMap = new WeakMap();
+
+  class Blob {
+    constructor(blobParts, options) {
+      if (arguments.length === 0) {
+        this[bytesSymbol] = new Uint8Array();
+        return;
+      }
+
+      const { ending = "transparent", type = "" } = options ?? {};
+      // Normalize options.type.
+      let normalizedType = type;
+      if (!containsOnlyASCII(type)) {
+        normalizedType = "";
+      } else {
+        if (type.length) {
+          for (let i = 0; i < type.length; ++i) {
+            const char = type[i];
+            if (char < "\u0020" || char > "\u007E") {
+              normalizedType = "";
+              break;
+            }
+          }
+          normalizedType = type.toLowerCase();
+        }
+      }
+      const bytes = processBlobParts(blobParts, { ending, type });
+      // Set Blob object's properties.
+      this[bytesSymbol] = bytes;
+      this.size = bytes.byteLength;
+      this.type = normalizedType;
+    }
+
+    slice(start, end, contentType) {
+      return new Blob([this[bytesSymbol].slice(start, end)], {
+        type: contentType || this.type,
+      });
+    }
+
+    stream() {
+      return getStream(this[bytesSymbol]);
+    }
+
+    async text() {
+      const reader = getStream(this[bytesSymbol]).getReader();
+      const decoder = new TextDecoder();
+      return decoder.decode(await readBytes(reader));
+    }
+
+    arrayBuffer() {
+      return readBytes(getStream(this[bytesSymbol]).getReader());
+    }
+  }
+
+  window.__bootstrap.blob = {
+    Blob,
+    bytesSymbol,
+    containsOnlyASCII,
+    blobBytesWeakMap,
+  };
+})(this);