Add HttpParser and UrlParser C++ wrappers for http_parser.

wpiutil/src/main/native/include/wpi/HttpParser.h

@@ -0,0 +1,216 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2018 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_WPI_HTTPPARSER_H_
+#define WPIUTIL_WPI_HTTPPARSER_H_
+
+#include <stdint.h>
+
+#include "wpi/Signal.h"
+#include "wpi/SmallString.h"
+#include "wpi/StringRef.h"
+#include "wpi/http_parser.h"
+
+namespace wpi {
+
+/**
+ * HTTP protocol parser.  Performs incremental parsing with callbacks for each
+ * part of the HTTP protocol.  As this is incremental, it's suitable for use
+ * with event based frameworks that provide arbitrary chunks of data.
+ */
+class HttpParser {
+ public:
+  enum Type {
+    kRequest = HTTP_REQUEST,
+    kResponse = HTTP_RESPONSE,
+    kBoth = HTTP_BOTH
+  };
+
+  /**
+   * Returns the library version. Bits 16-23 contain the major version number,
+   * bits 8-15 the minor version number and bits 0-7 the patch level.
+   */
+  static uint32_t GetParserVersion();
+
+  explicit HttpParser(Type type);
+
+  /**
+   * Set the maximum accepted length for URLs, field names, and field values.
+   * The default is 1024.
+   * @param len maximum length
+   */
+  void SetMaxLength(size_t len) { m_maxLength = len; }
+
+  /**
+   * Executes the parser.  An empty input is treated as EOF.
+   * @param in input data
+   * @return Number of parsed bytes.
+   */
+  size_t Execute(StringRef in) {
+    return http_parser_execute(&m_parser, &m_settings, in.data(), in.size());
+  }
+
+  /**
+   * Get HTTP major version.
+   */
+  unsigned int GetMajor() const { return m_parser.http_major; }
+
+  /**
+   * Get HTTP minor version.
+   */
+  unsigned int GetMinor() const { return m_parser.http_minor; }
+
+  /**
+   * Get HTTP status code.  Valid only on responses.  Valid in and after
+   * the OnStatus() callback has been called.
+   */
+  unsigned int GetStatusCode() const { return m_parser.status_code; }
+
+  /**
+   * Get HTTP method.  Valid only on requests.
+   */
+  http_method GetMethod() const {
+    return static_cast<http_method>(m_parser.method);
+  }
+
+  /**
+   * Determine if an error occurred.
+   * @return False if no error.
+   */
+  bool HasError() const { return m_parser.http_errno != HPE_OK; }
+
+  /**
+   * Get error number.
+   */
+  http_errno GetError() const {
+    return static_cast<http_errno>(m_parser.http_errno);
+  }
+
+  /**
+   * Abort the parse.  Call this from a callback handler to indicate an error.
+   * This will result in GetError() returning one of the callback-related
+   * errors (e.g. HPE_CB_message_begin).
+   */
+  void Abort() { m_aborted = true; }
+
+  /**
+   * Determine if an upgrade header was present and the parser has exited
+   * because of that.  Should be checked when Execute() returns in addition to
+   * checking GetError().
+   * @return True if upgrade header, false otherwise.
+   */
+  bool IsUpgrade() const { return m_parser.upgrade; }
+
+  /**
+   * If this returns false in the headersComplete or messageComplete
+   * callback, then this should be the last message on the connection.
+   * If you are the server, respond with the "Connection: close" header.
+   * If you are the client, close the connection.
+   */
+  bool ShouldKeepAlive() const { return http_should_keep_alive(&m_parser); }
+
+  /**
+   * Pause the parser.
+   * @param paused True to pause, false to unpause.
+   */
+  void Pause(bool paused) { http_parser_pause(&m_parser, paused); }
+
+  /**
+   * Checks if this is the final chunk of the body.
+   */
+  bool IsBodyFinal() const { return http_body_is_final(&m_parser); }
+
+  /**
+   * Get URL.  Valid in and after the url callback has been called.
+   */
+  StringRef GetUrl() const { return m_urlBuf; }
+
+  /**
+   * Message begin callback.
+   */
+  sig::Signal<> messageBegin;
+
+  /**
+   * URL callback.
+   *
+   * The parameter to the callback is the complete URL string.
+   */
+  sig::Signal<StringRef> url;
+
+  /**
+   * Status callback.
+   *
+   * The parameter to the callback is the complete status string.
+   * GetStatusCode() can be used to get the numeric status code.
+   */
+  sig::Signal<StringRef> status;
+
+  /**
+   * Header field callback.
+   *
+   * The parameters to the callback are the field name and field value.
+   */
+  sig::Signal<StringRef, StringRef> header;
+
+  /**
+   * Headers complete callback.
+   *
+   * The parameter to the callback is whether the connection should be kept
+   * alive.  If this is false, then this should be the last message on the
+   * connection.  If you are the server, respond with the "Connection: close"
+   * header.  If you are the client, close the connection.
+   */
+  sig::Signal<bool> headersComplete;
+
+  /**
+   * Body data callback.
+   *
+   * The parameters to the callback is the data chunk and whether this is the
+   * final chunk of data in the message.  Note this callback will be called
+   * multiple times arbitrarily (e.g. it's possible that it may be called with
+   * just a few characters at a time).
+   */
+  sig::Signal<StringRef, bool> body;
+
+  /**
+   * Headers complete callback.
+   *
+   * The parameter to the callback is whether the connection should be kept
+   * alive.  If this is false, then this should be the last message on the
+   * connection.  If you are the server, respond with the "Connection: close"
+   * header.  If you are the client, close the connection.
+   */
+  sig::Signal<bool> messageComplete;
+
+  /**
+   * Chunk header callback.
+   *
+   * The parameter to the callback is the chunk size.
+   */
+  sig::Signal<uint64_t> chunkHeader;
+
+  /**
+   * Chunk complete callback.
+   */
+  sig::Signal<> chunkComplete;
+
+ private:
+  http_parser m_parser;
+  http_parser_settings m_settings;
+
+  size_t m_maxLength = 1024;
+  enum { kStart, kUrl, kStatus, kField, kValue } m_state = kStart;
+  SmallString<128> m_urlBuf;
+  SmallString<32> m_fieldBuf;
+  SmallString<128> m_valueBuf;
+
+  bool m_aborted = false;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_WPI_HTTPPARSER_H_