Remove hardcoded mirrors, keep env var support

Author: Subham-KRLX

BUILD_CHINA.md

@@ -19,6 +19,45 @@
 
 # Building in China
 
+This guide helps developers in China who may experience network issues when downloading dependencies from GitHub or international mirrors.
+
+## Using Custom Mirror URLs
+
+If you experience download timeouts, you can override the default dependency URLs using environment variables:
+
+```bash
+export ICEBERG_ARROW_URL="<your-mirror-url>/apache-arrow-22.0.0.tar.gz"
+export ICEBERG_NANOARROW_URL="<your-mirror-url>/apache-arrow-nanoarrow-0.7.0.tar.gz"
+export ICEBERG_CROARING_URL="<your-mirror-url>/CRoaring-v4.3.11.tar.gz"
+export ICEBERG_NLOHMANN_JSON_URL="<your-mirror-url>/json-v3.11.3.tar.xz"
+export ICEBERG_SPDLOG_URL="<your-mirror-url>/spdlog-v1.15.3.tar.gz"
+export ICEBERG_CPR_URL="<your-mirror-url>/cpr-1.12.0.tar.gz"
+
+# For Avro (git repository):
+export ICEBERG_AVRO_GIT_URL="<your-git-mirror>/avro.git"
+# Or if you have a tarball:
+export ICEBERG_AVRO_URL="<your-mirror-url>/avro.tar.gz"
+```
+
+Then build as usual:
+
+```bash
+cmake -S . -B build
+cmake --build build
+```
+
+## Alternative Solutions
+
+1. **Use system packages**: Install dependencies via your system package manager
+2. **Use a proxy**: Set `https_proxy` environment variable
+3. **Pre-download**: Manually download tarballs to `~/.cmake/Downloads/`
+
+## Getting Help
+
+If you continue experiencing build issues, please open an issue at https://github.com/apache/iceberg-cpp/issues with details about which dependency failed.
+
+# Building in China
+
 This guide helps developers in China build iceberg-cpp when network access to GitHub and other international sites is limited.
 
 ## Mirror Support

cmake_modules/IcebergThirdpartyToolchain.cmake

@@ -33,8 +33,6 @@ else()
   set(ARROW_SOURCE_URL
       "https://www.apache.org/dyn/closer.lua?action=download&filename=/arrow/arrow-${ICEBERG_ARROW_BUILD_VERSION}/apache-arrow-${ICEBERG_ARROW_BUILD_VERSION}.tar.gz"
       "https://downloads.apache.org/arrow/arrow-${ICEBERG_ARROW_BUILD_VERSION}/apache-arrow-${ICEBERG_ARROW_BUILD_VERSION}.tar.gz"
-      "https://mirrors.tuna.tsinghua.edu.cn/apache/arrow/arrow-${ICEBERG_ARROW_BUILD_VERSION}/apache-arrow-${ICEBERG_ARROW_BUILD_VERSION}.tar.gz"
-      "https://mirrors.ustc.edu.cn/apache/arrow/arrow-${ICEBERG_ARROW_BUILD_VERSION}/apache-arrow-${ICEBERG_ARROW_BUILD_VERSION}.tar.gz"
   )
 endif()
 
@@ -253,9 +251,6 @@ function(resolve_nanoarrow_dependency)
   else()
     set(NANOARROW_URL
         "https://dlcdn.apache.org/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
-        "https://downloads.apache.org/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
-        "https://mirrors.tuna.tsinghua.edu.cn/apache/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
-        "https://mirrors.ustc.edu.cn/apache/arrow/apache-arrow-nanoarrow-0.7.0/apache-arrow-nanoarrow-0.7.0.tar.gz"
     )
   endif()
 
@@ -312,9 +307,7 @@ function(resolve_croaring_dependency)
     set(CROARING_URL "$ENV{ICEBERG_CROARING_URL}")
   else()
     set(CROARING_URL
-        "https://github.com/RoaringBitmap/CRoaring/archive/refs/tags/v4.3.11.tar.gz"
-        "https://gitee.com/mirrors/CRoaring/repository/archive/v4.3.11.tar.gz"
-        "https://hub.fastgit.xyz/RoaringBitmap/CRoaring/archive/refs/tags/v4.3.11.tar.gz")
+        "https://github.com/RoaringBitmap/CRoaring/archive/refs/tags/v4.3.11.tar.gz")
   endif()
 
   fetchcontent_declare(croaring
@@ -369,9 +362,7 @@ function(resolve_nlohmann_json_dependency)
     set(NLOHMANN_JSON_URL "$ENV{ICEBERG_NLOHMANN_JSON_URL}")
   else()
     set(NLOHMANN_JSON_URL
-        "https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz"
-        "https://gitee.com/mirrors/JSON-for-Modern-CPP/releases/download/v3.11.3/json.tar.xz"
-        "https://hub.fastgit.xyz/nlohmann/json/releases/download/v3.11.3/json.tar.xz")
+        "https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz")
   endif()
 
   fetchcontent_declare(nlohmann_json
@@ -437,10 +428,7 @@ function(resolve_spdlog_dependency)
   if(DEFINED ENV{ICEBERG_SPDLOG_URL})
     set(SPDLOG_URL "$ENV{ICEBERG_SPDLOG_URL}")
   else()
-    set(SPDLOG_URL
-        "https://github.com/gabime/spdlog/archive/refs/tags/v1.15.3.tar.gz"
-        "https://gitee.com/mirrors/spdlog/repository/archive/v1.15.3.tar.gz"
-        "https://hub.fastgit.xyz/gabime/spdlog/archive/refs/tags/v1.15.3.tar.gz")
+    set(SPDLOG_URL "https://github.com/gabime/spdlog/archive/refs/tags/v1.15.3.tar.gz")
   endif()
 
   fetchcontent_declare(spdlog
@@ -508,10 +496,7 @@ function(resolve_cpr_dependency)
   if(DEFINED ENV{ICEBERG_CPR_URL})
     set(CPR_URL "$ENV{ICEBERG_CPR_URL}")
   else()
-    set(CPR_URL
-        "https://github.com/libcpr/cpr/archive/refs/tags/1.12.0.tar.gz"
-        "https://gitee.com/mirrors/cpr/repository/archive/1.12.0.tar.gz"
-        "https://hub.fastgit.xyz/libcpr/cpr/archive/refs/tags/1.12.0.tar.gz")
+    set(CPR_URL "https://github.com/libcpr/cpr/archive/refs/tags/1.12.0.tar.gz")
   endif()
 
   fetchcontent_declare(cpr