Move some of the logic from egl_cache_t into FileBlobCache

HWUI is using BlobCache to implement SkSL shader cache very
similar to egl_cache_t. Create a new class FileBlobCache,
that is used by both egl_cache_t and HWUI. FileBlobCache adds
the logic to save and load the BlobCache from a memory mapped
file.

Test: Built and ran Android. Verified that EGL cache still works
Test: for gmail and calc apps.
Bug: 66740665
Change-Id: Ia4d194963d039a60244f3bc76108844418adc99d

1 files changed, 185 insertions, 0 deletions

diff --git a/opengl/libs/EGL/FileBlobCache.cpp b/opengl/libs/EGL/FileBlobCache.cpp
new file mode 100644
index 0000000000..ff608a38a4
--- /dev/null
+++ b/opengl/libs/EGL/FileBlobCache.cpp
@@ -0,0 +1,185 @@
+/*
+ ** Copyright 2017, The Android Open Source Project
+ **
+ ** Licensed under the Apache License, Version 2.0 (the "License");
+ ** you may not use this file except in compliance with the License.
+ ** You may obtain a copy of the License at
+ **
+ **     http://www.apache.org/licenses/LICENSE-2.0
+ **
+ ** Unless required by applicable law or agreed to in writing, software
+ ** distributed under the License is distributed on an "AS IS" BASIS,
+ ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ ** See the License for the specific language governing permissions and
+ ** limitations under the License.
+ */
+
+#include "FileBlobCache.h"
+
+#include <inttypes.h>
+#include <log/log.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+
+// Cache file header
+static const char* cacheFileMagic = "EGL$";
+static const size_t cacheFileHeaderSize = 8;
+
+namespace android {
+
+static uint32_t crc32c(const uint8_t* buf, size_t len) {
+    const uint32_t polyBits = 0x82F63B78;
+    uint32_t r = 0;
+    for (size_t i = 0; i < len; i++) {
+        r ^= buf[i];
+        for (int j = 0; j < 8; j++) {
+            if (r & 1) {
+                r = (r >> 1) ^ polyBits;
+            } else {
+                r >>= 1;
+            }
+        }
+    }
+    return r;
+}
+
+FileBlobCache::FileBlobCache(size_t maxKeySize, size_t maxValueSize, size_t maxTotalSize,
+        const std::string& filename)
+        : BlobCache(maxKeySize, maxValueSize, maxTotalSize)
+        , mFilename(filename) {
+    if (mFilename.length() > 0) {
+        size_t headerSize = cacheFileHeaderSize;
+
+        int fd = open(mFilename.c_str(), O_RDONLY, 0);
+        if (fd == -1) {
+            if (errno != ENOENT) {
+                ALOGE("error opening cache file %s: %s (%d)", mFilename.c_str(),
+                        strerror(errno), errno);
+            }
+            return;
+        }
+
+        struct stat statBuf;
+        if (fstat(fd, &statBuf) == -1) {
+            ALOGE("error stat'ing cache file: %s (%d)", strerror(errno), errno);
+            close(fd);
+            return;
+        }
+
+        // Sanity check the size before trying to mmap it.
+        size_t fileSize = statBuf.st_size;
+        if (fileSize > mMaxTotalSize * 2) {
+            ALOGE("cache file is too large: %#" PRIx64,
+                  static_cast<off64_t>(statBuf.st_size));
+            close(fd);
+            return;
+        }
+
+        uint8_t* buf = reinterpret_cast<uint8_t*>(mmap(NULL, fileSize,
+                PROT_READ, MAP_PRIVATE, fd, 0));
+        if (buf == MAP_FAILED) {
+            ALOGE("error mmaping cache file: %s (%d)", strerror(errno),
+                    errno);
+            close(fd);
+            return;
+        }
+
+        // Check the file magic and CRC
+        size_t cacheSize = fileSize - headerSize;
+        if (memcmp(buf, cacheFileMagic, 4) != 0) {
+            ALOGE("cache file has bad mojo");
+            close(fd);
+            return;
+        }
+        uint32_t* crc = reinterpret_cast<uint32_t*>(buf + 4);
+        if (crc32c(buf + headerSize, cacheSize) != *crc) {
+            ALOGE("cache file failed CRC check");
+            close(fd);
+            return;
+        }
+
+        int err = unflatten(buf + headerSize, cacheSize);
+        if (err < 0) {
+            ALOGE("error reading cache contents: %s (%d)", strerror(-err),
+                    -err);
+            munmap(buf, fileSize);
+            close(fd);
+            return;
+        }
+
+        munmap(buf, fileSize);
+        close(fd);
+    }
+}
+
+void FileBlobCache::writeToFile() {
+    if (mFilename.length() > 0) {
+        size_t cacheSize = getFlattenedSize();
+        size_t headerSize = cacheFileHeaderSize;
+        const char* fname = mFilename.c_str();
+
+        // Try to create the file with no permissions so we can write it
+        // without anyone trying to read it.
+        int fd = open(fname, O_CREAT | O_EXCL | O_RDWR, 0);
+        if (fd == -1) {
+            if (errno == EEXIST) {
+                // The file exists, delete it and try again.
+                if (unlink(fname) == -1) {
+                    // No point in retrying if the unlink failed.
+                    ALOGE("error unlinking cache file %s: %s (%d)", fname,
+                            strerror(errno), errno);
+                    return;
+                }
+                // Retry now that we've unlinked the file.
+                fd = open(fname, O_CREAT | O_EXCL | O_RDWR, 0);
+            }
+            if (fd == -1) {
+                ALOGE("error creating cache file %s: %s (%d)", fname,
+                        strerror(errno), errno);
+                return;
+            }
+        }
+
+        size_t fileSize = headerSize + cacheSize;
+
+        uint8_t* buf = new uint8_t [fileSize];
+        if (!buf) {
+            ALOGE("error allocating buffer for cache contents: %s (%d)",
+                    strerror(errno), errno);
+            close(fd);
+            unlink(fname);
+            return;
+        }
+
+        int err = flatten(buf + headerSize, cacheSize);
+        if (err < 0) {
+            ALOGE("error writing cache contents: %s (%d)", strerror(-err),
+                    -err);
+            delete [] buf;
+            close(fd);
+            unlink(fname);
+            return;
+        }
+
+        // Write the file magic and CRC
+        memcpy(buf, cacheFileMagic, 4);
+        uint32_t* crc = reinterpret_cast<uint32_t*>(buf + 4);
+        *crc = crc32c(buf + headerSize, cacheSize);
+
+        if (write(fd, buf, fileSize) == -1) {
+            ALOGE("error writing cache file: %s (%d)", strerror(errno),
+                    errno);
+            delete [] buf;
+            close(fd);
+            unlink(fname);
+            return;
+        }
+
+        delete [] buf;
+        fchmod(fd, S_IRUSR);
+        close(fd);
+    }
+}
+
+}
\ No newline at end of file