Issue #2692 - Part 2: Split out JS SourceBufferHolder to its own header.

js/public/SourceBufferHolder.h

@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Container class for passing in script source buffers to the JS engine.  This
+ * not only groups the buffer and length values, it also provides a way to
+ * optionally pass ownership of the buffer to the JS engine without copying.
+ * Rules for use:
+ *
+ *  1) The data array must be allocated with js_malloc() or js_realloc() if
+ *     ownership is being granted to the SourceBufferHolder.
+ *  2) If ownership is not given to the SourceBufferHolder, then the memory
+ *     must be kept alive until the JS compilation is complete.
+ *  3) Any code calling SourceBufferHolder::take() must guarantee to keep the
+ *     memory alive until JS compilation completes.  Normally only the JS
+ *     engine should be calling take().
+ *
+ * Example use:
+ *
+ *    size_t length = 512;
+ *    char16_t* chars = static_cast<char16_t*>(js_malloc(sizeof(char16_t) * length));
+ *    JS::SourceBufferHolder srcBuf(chars, length, JS::SourceBufferHolder::GiveOwnership);
+ *    JS::Compile(cx, options, srcBuf);
+ */
+
+#ifndef js_SourceBufferHolder_h
+#define js_SourceBufferHolder_h
+
+#include "mozilla/Assertions.h" // MOZ_ASSERT
+
+#include <stddef.h> // size_t
+
+#include "js/Utility.h" // JS::UniqueTwoByteChars
+
+namespace JS {
+
+class MOZ_STACK_CLASS SourceBufferHolder final
+{
+  public:
+    enum Ownership {
+      NoOwnership,
+      GiveOwnership
+    };
+
+    SourceBufferHolder(const char16_t* data, size_t dataLength, Ownership ownership)
+      : data_(data),
+        length_(dataLength),
+        ownsChars_(ownership == GiveOwnership)
+    {
+        // Ensure that null buffers properly return an unowned, empty,
+        // null-terminated string.
+        static const char16_t NullChar_ = 0;
+        if (!get()) {
+            data_ = &NullChar_;
+            length_ = 0;
+            ownsChars_ = false;
+        }
+    }
+
+    SourceBufferHolder(SourceBufferHolder&& other)
+      : data_(other.data_),
+        length_(other.length_),
+        ownsChars_(other.ownsChars_)
+    {
+        other.data_ = nullptr;
+        other.length_ = 0;
+        other.ownsChars_ = false;
+    }
+
+    ~SourceBufferHolder() {
+        if (ownsChars_)
+            js_free(const_cast<char16_t*>(data_));
+    }
+
+    // Access the underlying source buffer without affecting ownership.
+    const char16_t* get() const { return data_; }
+
+    // Length of the source buffer in char16_t code units (not bytes)
+    size_t length() const { return length_; }
+
+    // Returns true if the SourceBufferHolder owns the buffer and will free
+    // it upon destruction.  If true, it is legal to call take().
+    bool ownsChars() const { return ownsChars_; }
+
+    // Retrieve and take ownership of the underlying data buffer.  The caller
+    // is now responsible for calling js_free() on the returned value, *but only
+    // after JS script compilation has completed*.
+    //
+    // After the buffer has been taken the SourceBufferHolder functions as if
+    // it had been constructed on an unowned buffer;  get() and length() still
+    // work.  In order for this to be safe the taken buffer must be kept alive
+    // until after JS script compilation completes as noted above.
+    //
+    // Note, it's the caller's responsibility to check ownsChars() before taking
+    // the buffer.  Taking and then free'ing an unowned buffer will have dire
+    // consequences.
+    char16_t* take() {
+        MOZ_ASSERT(ownsChars_);
+        ownsChars_ = false;
+        return const_cast<char16_t*>(data_);
+    }
+
+  private:
+    SourceBufferHolder(SourceBufferHolder&) = delete;
+    SourceBufferHolder& operator=(SourceBufferHolder&) = delete;
+
+    const char16_t* data_;
+    size_t length_;
+    bool ownsChars_;
+};
+
+} // namespace JS
+
+#endif /* js_SourceBufferHolder_h */

js/src/jsapi.h

@@ -36,6 +36,7 @@
 #include "js/Principals.h"
 #include "js/Realm.h"
 #include "js/RootingAPI.h"
+#include "js/SourceBufferHolder.h"
 #include "js/Stream.h"
 #include "js/TracingAPI.h"
 #include "js/UniquePtr.h"
@@ -751,102 +752,6 @@ JS_StringHasBeenPinned(JSContext* cx, JSString* str);
 
 namespace JS {
 
-/**
- * Container class for passing in script source buffers to the JS engine.  This
- * not only groups the buffer and length values, it also provides a way to
- * optionally pass ownership of the buffer to the JS engine without copying.
- * Rules for use:
- *
- *  1) The data array must be allocated with js_malloc() or js_realloc() if
- *     ownership is being granted to the SourceBufferHolder.
- *  2) If ownership is not given to the SourceBufferHolder, then the memory
- *     must be kept alive until the JS compilation is complete.
- *  3) Any code calling SourceBufferHolder::take() must guarantee to keep the
- *     memory alive until JS compilation completes.  Normally only the JS
- *     engine should be calling take().
- *
- * Example use:
- *
- *    size_t length = 512;
- *    char16_t* chars = static_cast<char16_t*>(js_malloc(sizeof(char16_t) * length));
- *    JS::SourceBufferHolder srcBuf(chars, length, JS::SourceBufferHolder::GiveOwnership);
- *    JS::Compile(cx, options, srcBuf);
- */
-class MOZ_STACK_CLASS SourceBufferHolder final
-{
-  public:
-    enum Ownership {
-      NoOwnership,
-      GiveOwnership
-    };
-
-    SourceBufferHolder(const char16_t* data, size_t dataLength, Ownership ownership)
-      : data_(data),
-        length_(dataLength),
-        ownsChars_(ownership == GiveOwnership)
-    {
-        // Ensure that null buffers properly return an unowned, empty,
-        // null-terminated string.
-        static const char16_t NullChar_ = 0;
-        if (!get()) {
-            data_ = &NullChar_;
-            length_ = 0;
-            ownsChars_ = false;
-        }
-    }
-
-    SourceBufferHolder(SourceBufferHolder&& other)
-      : data_(other.data_),
-        length_(other.length_),
-        ownsChars_(other.ownsChars_)
-    {
-        other.data_ = nullptr;
-        other.length_ = 0;
-        other.ownsChars_ = false;
-    }
-
-    ~SourceBufferHolder() {
-        if (ownsChars_)
-            js_free(const_cast<char16_t*>(data_));
-    }
-
-    // Access the underlying source buffer without affecting ownership.
-    const char16_t* get() const { return data_; }
-
-    // Length of the source buffer in char16_t code units (not bytes)
-    size_t length() const { return length_; }
-
-    // Returns true if the SourceBufferHolder owns the buffer and will free
-    // it upon destruction.  If true, it is legal to call take().
-    bool ownsChars() const { return ownsChars_; }
-
-    // Retrieve and take ownership of the underlying data buffer.  The caller
-    // is now responsible for calling js_free() on the returned value, *but only
-    // after JS script compilation has completed*.
-    //
-    // After the buffer has been taken the SourceBufferHolder functions as if
-    // it had been constructed on an unowned buffer;  get() and length() still
-    // work.  In order for this to be safe the taken buffer must be kept alive
-    // until after JS script compilation completes as noted above.
-    //
-    // Note, it's the caller's responsibility to check ownsChars() before taking
-    // the buffer.  Taking and then free'ing an unowned buffer will have dire
-    // consequences.
-    char16_t* take() {
-        MOZ_ASSERT(ownsChars_);
-        ownsChars_ = false;
-        return const_cast<char16_t*>(data_);
-    }
-
-  private:
-    SourceBufferHolder(SourceBufferHolder&) = delete;
-    SourceBufferHolder& operator=(SourceBufferHolder&) = delete;
-
-    const char16_t* data_;
-    size_t length_;
-    bool ownsChars_;
-};
-
 } /* namespace JS */
 
 /************************************************************************/

js/src/moz.build

@@ -93,6 +93,7 @@ EXPORTS.js += [
     '../public/Result.h',
     '../public/RootingAPI.h',
     '../public/SliceBudget.h',
+    '../public/SourceBufferHolder.h',
     '../public/Stream.h',
     '../public/StructuredClone.h',
     '../public/SweepingAPI.h',