[Courgette] Refactor: Unify Disassembler::Disassemble() and instantiate AssemblyProgram there.

courgette/disassembler.h

Index: courgette/disassembler.h
diff --git a/courgette/disassembler.h b/courgette/disassembler.h
index ff2dd692a08c467da00a90ba359ebc0f385f3204..379a75aa376a745fb0521a7a264145643fac09e2 100644
--- a/courgette/disassembler.h
+++ b/courgette/disassembler.h
@@ -7,11 +7,13 @@
 
 #include <stdint.h>
 
+#include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "courgette/courgette.h"
 #include "courgette/image_utils.h"
+#include "courgette/instruction_utils.h"
 
 namespace courgette {
 
@@ -66,6 +68,12 @@ class Disassembler : public AddressTranslator {
   // general case of 64-bit architectures.
   virtual uint64_t image_base() const = 0;
 
+  // Extracts and stores locations of abs32 references from the image file.
+  virtual bool ExtractAbs32Locations() = 0;
+
+  // Extracts and stores locations of rel32 references from the image file.
+  virtual bool ExtractRel32Locations() = 0;
+
   // Returns a caller-owned new RvaVisitor to iterate through abs32 target RVAs.
   virtual RvaVisitor* CreateAbs32TargetRvaVisitor() = 0;
 
@@ -74,16 +82,18 @@ class Disassembler : public AddressTranslator {
 
   // Removes unused rel32 locations (architecture-specific). This is needed
   // because we may remove rel32 Labels along the way. As a result the matching
-  // matching rel32 addresses become unused. Removing them saves space.
+  // rel32 addresses become unused. Removing them saves space.
   virtual void RemoveUnusedRel32Locations(AssemblyProgram* program) = 0;
 
-  // Returns true if the buffer appears to be a valid executable of the expected
-  // type, and false otherwise. This needs not be called before Disassemble().
+  // Extracts structural data from the main image. Returns true if the image
+  // appears to be a valid executable of the expected type, or false otherwise.
+  // This needs to be called before Disassemble().
   virtual bool ParseHeader() = 0;
 
-  // Disassembles the item passed to the factory method into the output
-  // parameter 'program'.
-  virtual bool Disassemble(AssemblyProgram* program) = 0;
+  // Extracts and stores references from the main image. Returns a new
+  // AssemblyProgram initialized using data parsed from the main image, or null
+  // on failure.
+  std::unique_ptr<AssemblyProgram> Disassemble();
 
   // ok() may always be called but returns true only after ParseHeader()
   // succeeds.
@@ -112,6 +122,11 @@ class Disassembler : public AddressTranslator {
   // (or realloc) any memory. Usually only called via ParseHeader().
   void ReduceLength(size_t reduced_length);
 
+  // Returns a generator that emits instructions to a given receptor. |program|
+  // is required as helper.
+  virtual InstructionGenerator GetInstructionGenerator(
+      AssemblyProgram* program) = 0;
+
  private:
   const char* failure_reason_;