Add HTTPBodyStream interface, three concrete implementations, and their tests.

util/net/http_body.h

Index: util/net/http_body.h
diff --git a/util/net/http_body.h b/util/net/http_body.h
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+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_UTIL_NET_HTTP_BODY_H_
+#define CRASHPAD_UTIL_NET_HTTP_BODY_H_
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/files/file_path.h"
+
+namespace crashpad {
+
+//! \brief An interface to a stream that can be used for an HTTP request body.
+class HTTPBodyStream {
+ public:
+  virtual ~HTTPBodyStream() {}
+
+  //! \brief Copies up to \a max_len bytes into the user-supplied buffer.
+  //!
+  //! \param[out] buffer A user-supplied buffer into which this method will copy
+  //!      bytes from the stream.
+  //! \param[in] max_len The length (or size) of \a buffer. At most this many
+  //!     bytes will be copied.
+  //!
+  //! \return On success, a positive number indicating the number of bytes
+  //!     actually copied to \a buffer. On failure, a negative number. When
+  //!     the stream has no more data, returns `0`.
+  virtual ssize_t GetBytesBuffer(uint8_t* buffer, size_t max_len) = 0;
+
+ protected:
+  HTTPBodyStream() {}
+};
+
+//! \brief An implementation of HTTPBodyStream that turns a fixed string into
+//!     a stream.
+class StringHTTPBodyStream : public HTTPBodyStream {
+ public:
+  //! \brief Creates a stream with the specified string.
+  //!
+  //! \param[in] string The string to turn into a stream.
+  explicit StringHTTPBodyStream(const std::string& string);
+
+  ~StringHTTPBodyStream() override;
+
+  // HTTPBodyStream:
+  ssize_t GetBytesBuffer(uint8_t* buffer, size_t max_len) override;
+
+ private:
+  std::string string_;
+  size_t bytes_read_;
+
+  DISALLOW_COPY_AND_ASSIGN(StringHTTPBodyStream);
+};
+
+//! \brief An implementation of HTTPBodyStream that reads from the specified
+//!     file and provides its contents for an HTTP body.
+class FileHTTPBodyStream : public HTTPBodyStream {
+ public:
+  //! \brief Creates a stream for reading the file at the specified \a path.
+  //!
+  //! \param[in] path The file from which this HTTPBodyStream will read.
+  explicit FileHTTPBodyStream(const base::FilePath& path);
+
+  ~FileHTTPBodyStream() override;
+
+  // HTTPBodyStream:
+  ssize_t GetBytesBuffer(uint8_t* buffer, size_t max_len) override;
+
+ private:
+  enum InvalidFD {
+    kUnopenedFile = -1,
+    kFileOpenError = -2,
+    kClosedAtEOF = -3,
+  };
+
+  base::FilePath path_;
+
+  // If |fd_| is greater than or equal to zero, it is an opened descriptor
+  // from which an instance of this class is reading. If |fd_| is less than
+  // zero, the value corresponds to an InvalidFD value.
+  int fd_;
+
+  DISALLOW_COPY_AND_ASSIGN(FileHTTPBodyStream);
+};
+
+//! \brief An implementation of HTTPBodyStream that combines an array of
+//!     several other HTTPBodyStream objects into a single, unified stream.
+class CompositeHTTPBodyStream : public HTTPBodyStream {
+ public:
+  using PartsList = std::vector<HTTPBodyStream*>;
+
+  //! \brief Creates a stream from an array of other stream parts.
+  //!
+  //! \param[in] parts A vector of HTTPBodyStream objects, of which this object
+  //!     takes ownership, that will be represented as a single unified stream.
+  //!     Callers should not mutate the stream objects after passing them to
+  //!     an instance of this class.
+  explicit CompositeHTTPBodyStream(const PartsList& parts);
+
+  ~CompositeHTTPBodyStream() override;
+
+  // HTTPBodyStream:
+  ssize_t GetBytesBuffer(uint8_t* buffer, size_t max_len) override;
+
+ private:
+  PartsList parts_;
+  PartsList::iterator current_part_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompositeHTTPBodyStream);
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_UTIL_NET_HTTP_BODY_H_