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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /xpcom/io/nsIStreamBufferAccess.idl
parentInitial commit. (diff)
downloadfirefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/* -*- Mode: C++; tab-width: 4; 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/. */
+
+#include "nsISupports.idl"
+
+/**
+ * An interface for access to a buffering stream implementation's underlying
+ * memory buffer.
+ *
+ * Stream implementations that QueryInterface to nsIStreamBufferAccess must
+ * ensure that all buffers are aligned on the most restrictive type size for
+ * the current architecture (e.g., sizeof(double) for RISCy CPUs). malloc(3)
+ * satisfies this requirement.
+ */
+[scriptable, builtinclass, uuid(ac923b72-ac87-4892-ac7a-ca385d429435)]
+interface nsIStreamBufferAccess : nsISupports
+{
+ /**
+ * Get access to a contiguous, aligned run of bytes in the stream's buffer.
+ * Exactly one successful getBuffer call must occur before a putBuffer call
+ * taking the non-null pointer returned by the successful getBuffer.
+ *
+ * The run of bytes are the next bytes (modulo alignment padding) to read
+ * for an input stream, and the next bytes (modulo alignment padding) to
+ * store before (eventually) writing buffered data to an output stream.
+ * There can be space beyond this run of bytes in the buffer for further
+ * accesses before the fill or flush point is reached.
+ *
+ * @param aLength
+ * Count of contiguous bytes requested at the address A that satisfies
+ * (A & aAlignMask) == 0 in the buffer, starting from the current stream
+ * position, mapped to a buffer address B. The stream implementation
+ * must pad from B to A by skipping bytes (if input stream) or storing
+ * zero bytes (if output stream).
+ *
+ * @param aAlignMask
+ * Bit-mask computed by subtracting 1 from the power-of-two alignment
+ * modulus (e.g., 3 or sizeof(uint32_t)-1 for uint32_t alignment).
+ *
+ * @return
+ * The aligned pointer to aLength bytes in the buffer, or null if the
+ * buffer has no room for aLength bytes starting at the next address A
+ * after the current position that satisfies (A & aAlignMask) == 0.
+ */
+ [notxpcom,noscript] charPtr getBuffer(in uint32_t aLength, in uint32_t aAlignMask);
+
+ /**
+ * Relinquish access to the stream's buffer, filling if at end of an input
+ * buffer, flushing if completing an output buffer. After a getBuffer call
+ * that returns non-null, putBuffer must be called.
+ *
+ * @param aBuffer
+ * A non-null pointer returned by getBuffer on the same stream buffer
+ * access object.
+ *
+ * @param aLength
+ * The same count of contiguous bytes passed to the getBuffer call that
+ * returned aBuffer.
+ */
+ [notxpcom,noscript] void putBuffer(in charPtr aBuffer, in uint32_t aLength);
+
+ /**
+ * Disable and enable buffering on the stream implementing this interface.
+ * DisableBuffering flushes an output stream's buffer, and invalidates an
+ * input stream's buffer.
+ */
+ void disableBuffering();
+ void enableBuffering();
+
+ /**
+ * The underlying, unbuffered input or output stream.
+ */
+ readonly attribute nsISupports unbufferedStream;
+};
+
+%{C++
+
+/**
+ * These macros get and put a buffer given either an sba parameter that may
+ * point to an object implementing nsIStreamBufferAccess, nsIObjectInputStream,
+ * or nsIObjectOutputStream.
+ */
+#define NS_GET_BUFFER(sba,n,a) ((sba)->GetBuffer(n, a))
+#define NS_PUT_BUFFER(sba,p,n) ((sba)->PutBuffer(p, n))
+
+%}