move SK_MMAP_SUPPORT into SkPreConfig, so we can know about its availability

throughout the code.

Add SkData::NewFromMMap() help factory.

Refactor (now gone) SkMMapStream into SkStream::NewFromFile() factory
Review URL: https://codereview.chromium.org/12919013

git-svn-id: http://skia.googlecode.com/svn/trunk@8200 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 86 insertions, 77 deletions

diff --git a/src/core/SkData.cpp b/src/core/SkData.cpp
index 3e0c71a0e8..8fbca7af5f 100644
--- a/src/core/SkData.cpp
+++ b/src/core/SkData.cpp
@@ -8,6 +8,13 @@
 #include "SkData.h"
 #include "SkFlattenableBuffers.h"
 
+#if SK_MMAP_SUPPORT
+    #include <unistd.h>
+    #include <sys/mman.h>
+    #include <fcntl.h>
+    #include <errno.h>
+#endif
+
 SK_DEFINE_INST_COUNT(SkData)
 
 SkData::SkData(const void* ptr, size_t size, ReleaseProc proc, void* context) {
@@ -120,6 +127,20 @@ SkData* SkData::NewWithCString(const char cstr[]) {
     return NewWithCopy(cstr, size);
 }
 
+#if SK_MMAP_SUPPORT
+static void sk_munmap_releaseproc(const void* addr, size_t length, void*) {
+    munmap(const_cast<void*>(addr), length);
+}
+
+SkData* SkData::NewFromMMap(const void* addr, size_t length) {
+    return SkNEW_ARGS(SkData, (addr, length, sk_munmap_releaseproc, NULL));
+}
+#else
+SkData* SkData::NewFromMMap(const void* addr, size_t length) {
+    return NULL;
+}
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkData::flatten(SkFlattenableWriteBuffer& buffer) const {
@@ -300,3 +321,4 @@ SkDataSet* SkDataSet::NewEmpty() {
     gEmptySet->ref();
     return gEmptySet;
 }
+
diff --git a/src/core/SkMMapStream.cpp b/src/core/SkMMapStream.cpp
deleted file mode 100644
index 7388e81498..0000000000
--- a/src/core/SkMMapStream.cpp
+++ /dev/null
@@ -1,77 +0,0 @@
-
-/*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-#include "SkMMapStream.h"
-
-#include <unistd.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include <errno.h>
-
-SkMMAPStream::SkMMAPStream(const char filename[])
-{
-    fAddr = NULL;   // initialize to failure case
-    fSize = 0;
-
-    int fildes = open(filename, O_RDONLY);
-    if (fildes < 0)
-    {
-        SkDEBUGF(("---- failed to open(%s) for mmap stream error=%d\n", filename, errno));
-        return;
-    }
-
-    off_t offset = lseek(fildes, 0, SEEK_END);    // find the file size
-    if (offset == -1)
-    {
-        SkDEBUGF(("---- failed to lseek(%s) for mmap stream error=%d\n", filename, errno));
-        close(fildes);
-        return;
-    }
-    (void)lseek(fildes, 0, SEEK_SET);   // restore file offset to beginning
-
-    // to avoid a 64bit->32bit warning, I explicitly create a size_t size
-    size_t size = static_cast<size_t>(offset);
-
-    void* addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fildes, 0);
-
-    // According to the POSIX documentation of mmap it adds an extra reference
-    // to the file associated with the fildes which is not removed by a
-    // subsequent close() on that fildes. This reference is removed when there
-    // are no more mappings to the file.
-    close(fildes);
-
-    if (MAP_FAILED == addr)
-    {
-        SkDEBUGF(("---- failed to mmap(%s) for mmap stream error=%d\n", filename, errno));
-        return;
-    }
-
-    this->INHERITED::setMemory(addr, size);
-
-    fAddr = addr;
-    fSize = size;
-}
-
-SkMMAPStream::~SkMMAPStream()
-{
-    this->closeMMap();
-}
-
-void SkMMAPStream::setMemory(const void* data, size_t length, bool copyData)
-{
-    this->closeMMap();
-    this->INHERITED::setMemory(data, length, copyData);
-}
-
-void SkMMAPStream::closeMMap()
-{
-    if (fAddr)
-    {
-        munmap(fAddr, fSize);
-        fAddr = NULL;
-    }
-}
diff --git a/src/core/SkStream.cpp b/src/core/SkStream.cpp
index fb343ea76a..acbcfbc53d 100644
--- a/src/core/SkStream.cpp
+++ b/src/core/SkStream.cpp
@@ -13,6 +13,14 @@
 #include "SkString.h"
 #include "SkOSFile.h"
 
+#if SK_MMAP_SUPPORT
+    #include <unistd.h>
+    #include <sys/mman.h>
+    #include <fcntl.h>
+    #include <errno.h>
+    #include <unistd.h>
+#endif
+
 SK_DEFINE_INST_COUNT(SkStream)
 SK_DEFINE_INST_COUNT(SkWStream)
 SK_DEFINE_INST_COUNT(SkFILEStream)
@@ -789,3 +797,59 @@ bool SkDebugWStream::write(const void* buffer, size_t size)
 #endif
     return true;
 }
+
+///////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
+
+static bool mmap_filename(const char path[], void** addrPtr, size_t* sizePtr) {
+#if SK_MMAP_SUPPORT
+    int fd = open(path, O_RDONLY);
+    if (fd < 0) {
+        return false;
+    }
+    
+    off_t offset = lseek(fd, 0, SEEK_END);    // find the file size
+    if (offset == -1) {
+        close(fd);
+        return false;
+    }
+    (void)lseek(fd, 0, SEEK_SET);   // restore file offset to beginning
+    
+    // to avoid a 64bit->32bit warning, I explicitly create a size_t size
+    size_t size = static_cast<size_t>(offset);
+    
+    void* addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
+    close(fd);
+    
+    if (MAP_FAILED == addr) {
+        return false;
+    }
+    
+    *addrPtr = addr;
+    *sizePtr = size;
+    return true;
+#else
+    return false;
+#endif
+}
+
+SkStream* SkStream::NewFromFile(const char path[]) {
+    void* addr;
+    size_t size;
+    if (mmap_filename(path, &addr, &size)) {
+        SkAutoTUnref<SkData> data(SkData::NewFromMMap(addr, size));
+        if (data.get()) {
+            return SkNEW_ARGS(SkMemoryStream, (data.get()));
+        }
+    }
+    
+    // If we get here, then our attempt at using mmap failed, so try normal
+    // file access.
+    SkFILEStream* stream = SkNEW_ARGS(SkFILEStream, (path));
+    if (!stream->isValid()) {
+        stream->unref();
+        stream = NULL;
+    }
+    return stream;
+}
+