First round of dead file removal

obsolete/breakpad/common/linux/memory.h

-// Copyright (c) 2009, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#ifndef CLIENT_LINUX_HANDLER_MEMORY_H_
-#define CLIENT_LINUX_HANDLER_MEMORY_H_
-
-#include <stdint.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/mman.h>
-
-#include "common/linux/linux_syscall_support.h"
-
-namespace google_breakpad {
-
-// This is very simple allocator which fetches pages from the kernel directly.
-// Thus, it can be used even when the heap may be corrupted.
-//
-// There is no free operation. The pages are only freed when the object is
-// destroyed.
-class PageAllocator {
- public:
-  PageAllocator()
-      : page_size_(getpagesize()),
-        last_(NULL),
-        current_page_(NULL),
-        page_offset_(0) {
-  }
-
-  ~PageAllocator() {
-    FreeAll();
-  }
-
-  void *Alloc(unsigned bytes) {
-    if (!bytes)
-      return NULL;
-
-    if (current_page_ && page_size_ - page_offset_ >= bytes) {
-      uint8_t *const ret = current_page_ + page_offset_;
-      page_offset_ += bytes;
-      if (page_offset_ == page_size_) {
-        page_offset_ = 0;
-        current_page_ = NULL;
-      }
-
-      return ret;
-    }
-
-    const unsigned pages =
-        (bytes + sizeof(PageHeader) + page_size_ - 1) / page_size_;
-    uint8_t *const ret = GetNPages(pages);
-    if (!ret)
-      return NULL;
-
-    page_offset_ = (page_size_ - (page_size_ * pages - (bytes + sizeof(PageHeader)))) % page_size_;
-    current_page_ = page_offset_ ? ret + page_size_ * (pages - 1) : NULL;
-
-    return ret + sizeof(PageHeader);
-  }
-
- private:
-  uint8_t *GetNPages(unsigned num_pages) {
-#ifdef __x86_64
-    void *a = sys_mmap(NULL, page_size_ * num_pages, PROT_READ | PROT_WRITE,
-                       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-#else
-    void *a = sys_mmap2(NULL, page_size_ * num_pages, PROT_READ | PROT_WRITE,
-                        MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-#endif
-    if (a == MAP_FAILED)
-      return NULL;
-
-    struct PageHeader *header = reinterpret_cast<PageHeader*>(a);
-    header->next = last_;
-    header->num_pages = num_pages;
-    last_ = header;
-
-    return reinterpret_cast<uint8_t*>(a);
-  }
-
-  void FreeAll() {
-    PageHeader *next;
-
-    for (PageHeader *cur = last_; cur; cur = next) {
-      next = cur->next;
-      sys_munmap(cur, cur->num_pages * page_size_);
-    }
-  }
-
-  struct PageHeader {
-    PageHeader *next;  // pointer to the start of the next set of pages.
-    unsigned num_pages;  // the number of pages in this set.
-  };
-
-  const unsigned page_size_;
-  PageHeader *last_;
-  uint8_t *current_page_;
-  unsigned page_offset_;
-};
-
-// A wasteful vector is like a normal std::vector, except that it's very much
-// simplier and it allocates memory from a PageAllocator. It's wasteful
-// because, when resizing, it always allocates a whole new array since the
-// PageAllocator doesn't support realloc.
-template<class T>
-class wasteful_vector {
- public:
-  wasteful_vector(PageAllocator *allocator, unsigned size_hint = 16)
-      : allocator_(allocator),
-        a_((T*) allocator->Alloc(sizeof(T) * size_hint)),
-        allocated_(size_hint),
-        used_(0) {
-  }
-
-  void push_back(const T& new_element) {
-    if (used_ == allocated_)
-      Realloc(allocated_ * 2);
-    a_[used_++] = new_element;
-  }
-
-  size_t size() const {
-    return used_;
-  }
-
-  T& operator[](size_t index) {
-    return a_[index];
-  }
-
-  const T& operator[](size_t index) const {
-    return a_[index];
-  }
-
- private:
-  void Realloc(unsigned new_size) {
-    T *new_array =
-        reinterpret_cast<T*>(allocator_->Alloc(sizeof(T) * new_size));
-    memcpy(new_array, a_, used_ * sizeof(T));
-    a_ = new_array;
-    allocated_ = new_size;
-  }
-
-  PageAllocator *const allocator_;
-  T *a_;  // pointer to an array of |allocated_| elements.
-  unsigned allocated_;  // size of |a_|, in elements.
-  unsigned used_;  // number of used slots in |a_|.
-};
-
-}  // namespace google_breakpad
-
-inline void* operator new(size_t nbytes,
-                          google_breakpad::PageAllocator& allocator) {
-   return allocator.Alloc(nbytes);
-}
-
-#endif  // CLIENT_LINUX_HANDLER_MEMORY_H_