/* -*- indent-tabs-mode: nil; js-indent-level: 4 -*-
 * vim: sw=4 ts=4 sts=4 et filetype=javascript
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

var EXPORTED_SYMBOLS = ["NetUtil"];

/**
 * Necko utilities
 */

// //////////////////////////////////////////////////////////////////////////////
// // Constants

const PR_UINT32_MAX = 0xffffffff;

const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");

const BinaryInputStream = Components.Constructor(
  "@mozilla.org/binaryinputstream;1",
  "nsIBinaryInputStream",
  "setInputStream"
);

// //////////////////////////////////////////////////////////////////////////////
// // NetUtil Object

var NetUtil = {
  /**
   * Function to perform simple async copying from aSource (an input stream)
   * to aSink (an output stream).  The copy will happen on some background
   * thread.  Both streams will be closed when the copy completes.
   *
   * @param aSource
   *        The input stream to read from
   * @param aSink
   *        The output stream to write to
   * @param aCallback [optional]
   *        A function that will be called at copy completion with a single
   *        argument: the nsresult status code for the copy operation.
   *
   * @return An nsIRequest representing the copy operation (for example, this
   *         can be used to cancel the copying).  The consumer can ignore the
   *         return value if desired.
   */
  asyncCopy: function NetUtil_asyncCopy(aSource, aSink, aCallback = null) {
    if (!aSource || !aSink) {
      let exception = new Components.Exception(
        "Must have a source and a sink",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
      throw exception;
    }

    // make a stream copier
    var copier = Cc[
      "@mozilla.org/network/async-stream-copier;1"
    ].createInstance(Ci.nsIAsyncStreamCopier2);
    copier.init(
      aSource,
      aSink,
      null /* Default event target */,
      0 /* Default length */,
      true,
      true /* Auto-close */
    );

    var observer;
    if (aCallback) {
      observer = {
        onStartRequest(aRequest) {},
        onStopRequest(aRequest, aStatusCode) {
          aCallback(aStatusCode);
        },
      };
    } else {
      observer = null;
    }

    // start the copying
    copier.QueryInterface(Ci.nsIAsyncStreamCopier).asyncCopy(observer, null);
    return copier;
  },

  /**
   * Asynchronously opens a source and fetches the response.  While the fetch
   * is asynchronous, I/O may happen on the main thread.  When reading from
   * a local file, prefer using "OS.File" methods instead.
   *
   * @param aSource
   *        This argument can be one of the following:
   *         - An options object that will be passed to NetUtil.newChannel.
   *         - An existing nsIChannel.
   *         - An existing nsIInputStream.
   *        Using an nsIURI, nsIFile, or string spec directly is deprecated.
   * @param aCallback
   *        The callback function that will be notified upon completion.  It
   *        will get these arguments:
   *        1) An nsIInputStream containing the data from aSource, if any.
   *        2) The status code from opening the source.
   *        3) Reference to the nsIRequest.
   */
  asyncFetch: function NetUtil_asyncFetch(aSource, aCallback) {
    if (!aSource || !aCallback) {
      let exception = new Components.Exception(
        "Must have a source and a callback",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
      throw exception;
    }

    // Create a pipe that will create our output stream that we can use once
    // we have gotten all the data.
    let pipe = Cc["@mozilla.org/pipe;1"].createInstance(Ci.nsIPipe);
    pipe.init(true, true, 0, PR_UINT32_MAX, null);

    // Create a listener that will give data to the pipe's output stream.
    let listener = Cc[
      "@mozilla.org/network/simple-stream-listener;1"
    ].createInstance(Ci.nsISimpleStreamListener);
    listener.init(pipe.outputStream, {
      onStartRequest(aRequest) {},
      onStopRequest(aRequest, aStatusCode) {
        pipe.outputStream.close();
        aCallback(pipe.inputStream, aStatusCode, aRequest);
      },
    });

    // Input streams are handled slightly differently from everything else.
    if (aSource instanceof Ci.nsIInputStream) {
      let pump = Cc["@mozilla.org/network/input-stream-pump;1"].createInstance(
        Ci.nsIInputStreamPump
      );
      pump.init(aSource, 0, 0, true);
      pump.asyncRead(listener, null);
      return;
    }

    let channel = aSource;
    if (!(channel instanceof Ci.nsIChannel)) {
      channel = this.newChannel(aSource);
    }

    try {
      channel.asyncOpen(listener);
    } catch (e) {
      let exception = new Components.Exception(
        "Failed to open input source '" + channel.originalURI.spec + "'",
        e.result,
        Components.stack.caller,
        aSource,
        e
      );
      throw exception;
    }
  },

  /**
   * Constructs a new URI for the given spec, character set, and base URI, or
   * an nsIFile.
   *
   * @param aTarget
   *        The string spec for the desired URI or an nsIFile.
   * @param aOriginCharset [optional]
   *        The character set for the URI.  Only used if aTarget is not an
   *        nsIFile.
   * @param aBaseURI [optional]
   *        The base URI for the spec.  Only used if aTarget is not an
   *        nsIFile.
   *
   * @return an nsIURI object.
   */
  newURI: function NetUtil_newURI(aTarget, aOriginCharset, aBaseURI) {
    if (!aTarget) {
      let exception = new Components.Exception(
        "Must have a non-null string spec or nsIFile object",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
      throw exception;
    }

    if (aTarget instanceof Ci.nsIFile) {
      return Services.io.newFileURI(aTarget);
    }

    return Services.io.newURI(aTarget, aOriginCharset, aBaseURI);
  },

  /**
   * Constructs a new channel for the given source.
   *
   * Keep in mind that URIs coming from a webpage should *never* use the
   * systemPrincipal as the loadingPrincipal.
   *
   * @param aWhatToLoad
   *        This argument used to be a string spec for the desired URI, an
   *        nsIURI, or an nsIFile.  Now it should be an options object with
   *        the following properties:
   *        {
   *          uri:
   *            The full URI spec string, nsIURI or nsIFile to create the
   *            channel for.
   *            Note that this cannot be an nsIFile if you have to specify a
   *            non-default charset or base URI.  Call NetUtil.newURI first if
   *            you need to construct an URI using those options.
   *          loadingNode:
   *          loadingPrincipal:
   *          triggeringPrincipal:
   *          securityFlags:
   *          contentPolicyType:
   *            These will be used as values for the nsILoadInfo object on the
   *            created channel. For details, see nsILoadInfo in nsILoadInfo.idl
   *          loadUsingSystemPrincipal:
   *            Set this to true to use the system principal as
   *            loadingPrincipal.  This must be omitted if loadingPrincipal or
   *            loadingNode are present.
   *            This should be used with care as it skips security checks.
   *        }
   * @return an nsIChannel object.
   */
  newChannel: function NetUtil_newChannel(aWhatToLoad) {
    // Make sure the API is called using only the options object.
    if (typeof aWhatToLoad != "object" || arguments.length != 1) {
      throw new Components.Exception(
        "newChannel requires a single object argument",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
    }

    let {
      uri,
      loadingNode,
      loadingPrincipal,
      loadUsingSystemPrincipal,
      triggeringPrincipal,
      securityFlags,
      contentPolicyType,
    } = aWhatToLoad;

    if (!uri) {
      throw new Components.Exception(
        "newChannel requires the 'uri' property on the options object.",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
    }

    if (typeof uri == "string" || uri instanceof Ci.nsIFile) {
      uri = this.newURI(uri);
    }

    if (!loadingNode && !loadingPrincipal && !loadUsingSystemPrincipal) {
      throw new Components.Exception(
        "newChannel requires at least one of the 'loadingNode'," +
          " 'loadingPrincipal', or 'loadUsingSystemPrincipal'" +
          " properties on the options object.",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
    }

    if (loadUsingSystemPrincipal === true) {
      if (loadingNode || loadingPrincipal) {
        throw new Components.Exception(
          "newChannel does not accept 'loadUsingSystemPrincipal'" +
            " if the 'loadingNode' or 'loadingPrincipal' properties" +
            " are present on the options object.",
          Cr.NS_ERROR_INVALID_ARG,
          Components.stack.caller
        );
      }
      loadingPrincipal = Services.scriptSecurityManager.getSystemPrincipal();
    } else if (loadUsingSystemPrincipal !== undefined) {
      throw new Components.Exception(
        "newChannel requires the 'loadUsingSystemPrincipal'" +
          " property on the options object to be 'true' or 'undefined'.",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
    }

    if (securityFlags === undefined) {
      if (!loadUsingSystemPrincipal) {
        throw new Components.Exception(
          "newChannel requires the 'securityFlags' property on" +
            " the options object unless loading from system principal.",
          Cr.NS_ERROR_INVALID_ARG,
          Components.stack.caller
        );
      }
      securityFlags = Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL;
    }

    if (contentPolicyType === undefined) {
      if (!loadUsingSystemPrincipal) {
        throw new Components.Exception(
          "newChannel requires the 'contentPolicyType' property on" +
            " the options object unless loading from system principal.",
          Cr.NS_ERROR_INVALID_ARG,
          Components.stack.caller
        );
      }
      contentPolicyType = Ci.nsIContentPolicy.TYPE_OTHER;
    }

    let channel = Services.io.newChannelFromURI(
      uri,
      loadingNode || null,
      loadingPrincipal || null,
      triggeringPrincipal || null,
      securityFlags,
      contentPolicyType
    );
    if (loadUsingSystemPrincipal) {
      channel.loadInfo.allowDeprecatedSystemRequests = true;
    }
    return channel;
  },

  /**
   * Reads aCount bytes from aInputStream into a string.
   *
   * @param aInputStream
   *        The input stream to read from.
   * @param aCount
   *        The number of bytes to read from the stream.
   * @param aOptions [optional]
   *        charset
   *          The character encoding of stream data.
   *        replacement
   *          The character to replace unknown byte sequences.
   *          If unset, it causes an exceptions to be thrown.
   *
   * @return the bytes from the input stream in string form.
   *
   * @throws NS_ERROR_INVALID_ARG if aInputStream is not an nsIInputStream.
   * @throws NS_BASE_STREAM_WOULD_BLOCK if reading from aInputStream would
   *         block the calling thread (non-blocking mode only).
   * @throws NS_ERROR_FAILURE if there are not enough bytes available to read
   *         aCount amount of data.
   * @throws NS_ERROR_ILLEGAL_INPUT if aInputStream has invalid sequences
   */
  readInputStreamToString: function NetUtil_readInputStreamToString(
    aInputStream,
    aCount,
    aOptions
  ) {
    if (!(aInputStream instanceof Ci.nsIInputStream)) {
      let exception = new Components.Exception(
        "First argument should be an nsIInputStream",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
      throw exception;
    }

    if (!aCount) {
      let exception = new Components.Exception(
        "Non-zero amount of bytes must be specified",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
      throw exception;
    }

    if (aOptions && "charset" in aOptions) {
      let cis = Cc["@mozilla.org/intl/converter-input-stream;1"].createInstance(
        Ci.nsIConverterInputStream
      );
      try {
        // When replacement is set, the character that is unknown sequence
        // replaces with aOptions.replacement character.
        if (!("replacement" in aOptions)) {
          // aOptions.replacement isn't set.
          // If input stream has unknown sequences for aOptions.charset,
          // throw NS_ERROR_ILLEGAL_INPUT.
          aOptions.replacement = 0;
        }

        cis.init(aInputStream, aOptions.charset, aCount, aOptions.replacement);
        let str = {};
        cis.readString(-1, str);
        cis.close();
        return str.value;
      } catch (e) {
        // Adjust the stack so it throws at the caller's location.
        throw new Components.Exception(
          e.message,
          e.result,
          Components.stack.caller,
          e.data
        );
      }
    }

    let sis = Cc["@mozilla.org/scriptableinputstream;1"].createInstance(
      Ci.nsIScriptableInputStream
    );
    sis.init(aInputStream);
    try {
      return sis.readBytes(aCount);
    } catch (e) {
      // Adjust the stack so it throws at the caller's location.
      throw new Components.Exception(
        e.message,
        e.result,
        Components.stack.caller,
        e.data
      );
    }
  },

  /**
   * Reads aCount bytes from aInputStream into a string.
   *
   * @param {nsIInputStream} aInputStream
   *        The input stream to read from.
   * @param {integer} [aCount = aInputStream.available()]
   *        The number of bytes to read from the stream.
   *
   * @return the bytes from the input stream in string form.
   *
   * @throws NS_ERROR_INVALID_ARG if aInputStream is not an nsIInputStream.
   * @throws NS_BASE_STREAM_WOULD_BLOCK if reading from aInputStream would
   *         block the calling thread (non-blocking mode only).
   * @throws NS_ERROR_FAILURE if there are not enough bytes available to read
   *         aCount amount of data.
   */
  readInputStream(aInputStream, aCount) {
    if (!(aInputStream instanceof Ci.nsIInputStream)) {
      let exception = new Components.Exception(
        "First argument should be an nsIInputStream",
        Cr.NS_ERROR_INVALID_ARG,
        Components.stack.caller
      );
      throw exception;
    }

    if (!aCount) {
      aCount = aInputStream.available();
    }

    let stream = new BinaryInputStream(aInputStream);
    let result = new ArrayBuffer(aCount);
    stream.readArrayBuffer(result.byteLength, result);
    return result;
  },
};