Bug 1875218 - Remove _MappableBuffer. r=gsvelto

Now that its last use was removed with MappableDeflate, it can be
removed.

Differential Revision: https://phabricator.services.mozilla.com/D198914

mozglue/linker/Mappable.cpp

@@ -3,18 +3,10 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include <fcntl.h>
-#include <sys/mman.h>
 #include <sys/stat.h>
 
 #include "Mappable.h"
 
-#include "mozilla/IntegerPrintfMacros.h"
-
-#ifdef ANDROID
-#  include "mozilla/Ashmem.h"
-#endif
-#include "Logging.h"
-
 Mappable* MappableFile::Create(const char* path) {
   int fd = open(path, O_RDONLY);
   if (fd != -1) return new MappableFile(fd);
@@ -40,72 +32,3 @@ size_t MappableFile::GetLength() const {
   struct stat st;
   return fstat(fd, &st) ? 0 : st.st_size;
 }
-
-/**
- * _MappableBuffer is a buffer which content can be mapped at different
- * locations in the virtual address space.
- * On Linux, uses a (deleted) temporary file on a tmpfs for sharable content.
- * On Android, uses ashmem.
- */
-class _MappableBuffer : public MappedPtr {
- public:
-  /**
-   * Returns a _MappableBuffer instance with the given name and the given
-   * length.
-   */
-  static _MappableBuffer* Create(const char* name, size_t length) {
-    AutoCloseFD fd;
-    const char* ident;
-#ifdef ANDROID
-    /* On Android, initialize an ashmem region with the given length */
-    fd = mozilla::android::ashmem_create(name, length);
-    ident = name;
-#else
-    /* On Linux, use /dev/shm as base directory for temporary files, assuming
-     * it's on tmpfs */
-    /* TODO: check that /dev/shm is tmpfs */
-    char path[256];
-    sprintf(path, "/dev/shm/%s.XXXXXX", name);
-    fd = mkstemp(path);
-    if (fd == -1) return nullptr;
-    unlink(path);
-    ftruncate(fd, length);
-    ident = path;
-#endif
-
-    void* buf =
-        ::mmap(nullptr, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-    if (buf != MAP_FAILED) {
-      DEBUG_LOG("Decompression buffer of size 0x%" PRIxPTR
-                " in "
-#ifdef ANDROID
-                "ashmem "
-#endif
-                "\"%s\", mapped @%p",
-                length, ident, buf);
-      return new _MappableBuffer(fd.forget(), buf, length);
-    }
-    return nullptr;
-  }
-
-  void* mmap(const void* addr, size_t length, int prot, int flags,
-             off_t offset) {
-    MOZ_ASSERT(fd != -1);
-#ifdef ANDROID
-    /* Mapping ashmem MAP_PRIVATE is like mapping anonymous memory, even when
-     * there is content in the ashmem */
-    if (flags & MAP_PRIVATE) {
-      flags &= ~MAP_PRIVATE;
-      flags |= MAP_SHARED;
-    }
-#endif
-    return ::mmap(const_cast<void*>(addr), length, prot, flags, fd, offset);
-  }
-
- private:
-  _MappableBuffer(int fd, void* buf, size_t length)
-      : MappedPtr(buf, length), fd(fd) {}
-
-  /* File descriptor for the temporary file or ashmem */
-  AutoCloseFD fd;
-};

mozglue/linker/Mappable.h

@@ -77,6 +77,4 @@ class MappableFile : public Mappable {
   AutoCloseFD fd;
 };
 
-class _MappableBuffer;
-
 #endif /* Mappable_h */