Merge StreamableMemoryObject into MemoryObject.

[oota-llvm.git] / include / llvm / Support / MemoryObject.h

diff --git a/include/llvm/Support/MemoryObject.h b/include/llvm/Support/MemoryObject.h
index 6208772532c3fe8065c218423b301ac3087080ff..584a2c55c04005d84f19928dc12b82eac84339b8 100644 (file)
--- a/include/llvm/Support/MemoryObject.h
+++ b/include/llvm/Support/MemoryObject.h
@@ -14,10 +14,17 @@
 
 namespace llvm {
 
-/// Abstract base class for contiguous addressable memory. Necessary for cases
-/// in which the memory is in another process, in a file, or on a remote
-/// machine. All size and offset parameters are uint64_ts, to allow 32-bit
-/// processes access to 64-bit address spaces.
+/// Interface to data which might be streamed. Streamability has 2 important
+/// implications/restrictions. First, the data might not yet exist in memory
+/// when the request is made. This just means that readByte/readBytes might have
+/// to block or do some work to get it. More significantly, the exact size of
+/// the object might not be known until it has all been fetched. This means that
+/// to return the right result, getExtent must also wait for all the data to
+/// arrive; therefore it should not be called on objects which are actually
+/// streamed (this would defeat the purpose of streaming). Instead,
+/// isValidAddress and isObjectEnd can be used to test addresses without knowing
+/// the exact size of the stream. Finally, getPointer can be used instead of
+/// readBytes to avoid extra copying.
 class MemoryObject {
 public:
   virtual ~MemoryObject();
@@ -41,6 +48,28 @@ public:
   ///                   bounds violation or an implementation-specific error.
   virtual int readBytes(uint64_t address, uint64_t size,
                         uint8_t *buf) const = 0;
+
+  /// Ensures that the requested data is in memory, and returns a pointer to it.
+  /// More efficient than using readBytes if the data is already in memory. May
+  /// block until (address - base + size) bytes have been read
+  /// @param address - address of the byte, in the same space as getBase()
+  /// @param size    - amount of data that must be available on return
+  /// @result        - valid pointer to the requested data
+  virtual const uint8_t *getPointer(uint64_t address, uint64_t size) const = 0;
+
+  /// Returns true if the address is within the object (i.e. between base and
+  /// base + extent - 1 inclusive). May block until (address - base) bytes have
+  /// been read
+  /// @param address - address of the byte, in the same space as getBase()
+  /// @result        - true if the address may be read with readByte()
+  virtual bool isValidAddress(uint64_t address) const = 0;
+
+  /// Returns true if the address is one past the end of the object (i.e. if it
+  /// is equal to base + extent). May block until (address - base) bytes have
+  /// been read
+  /// @param address - address of the byte, in the same space as getBase()
+  /// @result        - true if the address is equal to base + extent
+  virtual bool isObjectEnd(uint64_t address) const = 0;
 };
 
 }