fix: improve glog detection and fix install permission issues

1. glog detection improvements:
   - Try find_package(glog) first
   - Fallback to pkg-config with proper LINK_LIBRARIES
   - Try direct library search in common paths
   - Final fallback to -lglog linker flag
   - Remove FATAL_ERROR to allow build to proceed

2. Fix third-party library install permissions:
   - Set CMAKE_INSTALL_PREFIX to local build/install directory
   - Prevents permission denied errors when installing to /usr/local
   - Applies to GTI, IP-DiskANN, and PLSH

3. Add ALGORITHMS_IMPL_DIR variable at script start
   - Used for local install prefix paths
   - Create build/install directory upfront

This should fix both the 'glog not found' CMake error and the
'Permission denied' install errors.

Author: MingqiWang-coder

algorithms_impl/CMakeLists.txt

@@ -143,25 +143,35 @@ if(TORCH_PYTHON_LIBRARY)
 endif()
 
 # 必需: glog (必须在 DiskANN 之前，因为 DiskANN 依赖它)
-find_package(PkgConfig)
-if(PKG_CONFIG_FOUND)
-    pkg_check_modules(GLOG libglog)
-    if(GLOG_FOUND)
-        list(APPEND PYCANDY_LIBS ${GLOG_LIBRARIES})
-        message(STATUS "Found glog via pkg-config: ${GLOG_LIBRARIES}")
-    else()
-        find_library(GLOG_LIB glog)
+# 尝试多种方式查找 glog
+find_package(glog QUIET)
+if(glog_FOUND)
+    list(APPEND PYCANDY_LIBS glog::glog)
+    message(STATUS "Found glog via find_package")
+else()
+    # 尝试使用 pkg-config
+    find_package(PkgConfig QUIET)
+    if(PKG_CONFIG_FOUND)
+        pkg_check_modules(GLOG libglog QUIET)
+        if(GLOG_FOUND)
+            list(APPEND PYCANDY_LIBS ${GLOG_LINK_LIBRARIES})
+            include_directories(${GLOG_INCLUDE_DIRS})
+            message(STATUS "Found glog via pkg-config: ${GLOG_LINK_LIBRARIES}")
+        endif()
+    endif()
+    
+    # 如果还是找不到，尝试直接查找库文件
+    if(NOT GLOG_FOUND)
+        find_library(GLOG_LIB glog PATHS /usr/lib /usr/local/lib /usr/lib/x86_64-linux-gnu)
         if(GLOG_LIB)
             list(APPEND PYCANDY_LIBS ${GLOG_LIB})
-            message(STATUS "Found glog: ${GLOG_LIB}")
+            message(STATUS "Found glog library: ${GLOG_LIB}")
         else()
-            message(FATAL_ERROR "glog not found - required for PyCANDYAlgo")
+            # 最后的尝试：直接链接 -lglog
+            list(APPEND PYCANDY_LIBS glog)
+            message(WARNING "glog not found via find_package or pkg-config, linking with -lglog")
         endif()
     endif()
-else()
-    find_library(GLOG_LIB glog REQUIRED)
-    list(APPEND PYCANDY_LIBS ${GLOG_LIB})
-    message(STATUS "Found glog: ${GLOG_LIB}")
 endif()
 
 # 可选: aio

algorithms_impl/build.sh

@@ -3,6 +3,9 @@
 
 set -e  # 遇到错误立即退出
 
+# 获取脚本所在目录的绝对路径
+ALGORITHMS_IMPL_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
 echo "========================================="
 echo "Building PyCANDYAlgo Module"
 echo "========================================="
@@ -26,8 +29,9 @@ if [ -d "build" ]; then
     rm -rf build
 fi
 
-# 创建构建目录
+# 创建构建目录和安装目录
 mkdir -p build
+mkdir -p build/install
 cd build
 
 echo ""
@@ -236,7 +240,7 @@ if [ -d "gti/GTI" ]; then
     fi
     mkdir -p bin build
     cd build
-    cmake -DCMAKE_BUILD_TYPE=Release .. || { echo "❌ GTI cmake failed"; exit 1; }
+    cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX="$ALGORITHMS_IMPL_DIR/build/install" .. || { echo "❌ GTI cmake failed"; exit 1; }
     make -j${JOBS} || { echo "❌ GTI build failed"; exit 1; }
     make install || echo "  ⚠ GTI install failed (not critical)"
     cd ../../..
@@ -257,7 +261,7 @@ if [ -d "ipdiskann" ]; then
     fi
     mkdir -p build
     cd build
-    cmake .. || { echo "❌ IP-DiskANN cmake failed"; exit 1; }
+    cmake -DCMAKE_INSTALL_PREFIX="$ALGORITHMS_IMPL_DIR/build/install" .. || { echo "❌ IP-DiskANN cmake failed"; exit 1; }
     make -j${JOBS} || { echo "❌ IP-DiskANN build failed"; exit 1; }
     make install || echo "  ⚠ IP-DiskANN install failed (not critical)"
     cd ../..
@@ -278,7 +282,7 @@ if [ -d "plsh" ]; then
     fi
     mkdir -p build
     cd build
-    cmake .. || { echo "❌ PLSH cmake failed"; exit 1; }
+    cmake -DCMAKE_INSTALL_PREFIX="$ALGORITHMS_IMPL_DIR/build/install" .. || { echo "❌ PLSH cmake failed"; exit 1; }
     make -j${JOBS} || { echo "❌ PLSH build failed"; exit 1; }
     make install || echo "  ⚠ PLSH install failed (not critical)"
     cd ../..