Clean up all explict DataLoader usage

Author: haochengxia

docs/src/en/getting_started/quickstart.md

@@ -91,11 +91,10 @@ With libcachesim installed, you can start cache simulation for some eviction alg
 
 The above example demonstrates the basic workflow of using `libcachesim` for cache simulation:
 
-1. Use `DataLoader` to download a cache trace file from an S3 bucket.
-2. Open and efficiently process the trace file with `TraceReader`.
-3. Initialize a cache object (here, `S3FIFO`) with a specified cache size (e.g., 1MB).
-4. Run the simulation on the entire trace using `process_trace` to obtain object and byte miss ratios.
-5. Optionally, process only a portion of the trace by specifying `start_req` and `max_req` for partial simulation.
+1. Open and efficiently process the trace file with `TraceReader`.
+2. Initialize a cache object (here, `S3FIFO`) with a specified cache size (e.g., 1MB).
+3. Run the simulation on the entire trace using `process_trace` to obtain object and byte miss ratios.
+4. Optionally, process only a portion of the trace by specifying `start_req` and `max_req` for partial simulation.
 
 This workflow applies to most cache algorithms and trace types, making it easy to get started and customize your experiments.
 
@@ -108,10 +107,7 @@ Here is an example demonstrating how to use `TraceAnalyzer`.
     import libcachesim as lcs
 
     # Step 1: Get one trace from S3 bucket
-    URI = "cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"
-    dl = lcs.DataLoader()
-    dl.load(URI)
-
+    URI = "s3://cache-datasets/cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"
     reader = lcs.TraceReader(
         trace = dl.get_cache_path(URI),
         trace_type = lcs.TraceType.ORACLE_GENERAL_TRACE,
@@ -143,8 +139,7 @@ Here is an example demonstrating how to use `TraceAnalyzer`.
 
 The above code demonstrates how to perform trace analysis using `libcachesim`. The workflow is as follows:
 
-1. Download a trace file from an S3 bucket using `DataLoader`.
-2. Open the trace file with `TraceReader`, specifying the trace type and any reader initialization parameters.
+1. Open the trace file with `TraceReader`, specifying the trace type and any reader initialization parameters. The URI starting with `s3://`, will download a trace file from an S3 bucket.
 3. Configure the analysis options with `AnalysisOption` to enable or disable specific analyses (such as request rate, size, etc.).
 4. Optionally, set additional analysis parameters with `AnalysisParam`.
 5. Create a `TraceAnalyzer` object with the reader, output directory, and the chosen options and parameters.

examples/plugin_cache/s3fifo.py

@@ -193,17 +193,16 @@ def cache_free_hook(cache):
     cache_name="S3FIFO",
 )
 
-URI = "cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"
-dl = lcs.DataLoader()
-dl.load(URI)
+URI = "s3://cache-datasets/cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"
 
-# Step 2: Open trace and process efficiently
+# Open trace
 reader = lcs.TraceReader(
-    trace=dl.get_cache_path(URI),
+    trace=URI,
     trace_type=lcs.TraceType.ORACLE_GENERAL_TRACE,
     reader_init_params=lcs.ReaderInitParam(ignore_obj_size=True),
 )
 
+# Use native S3FIFO for reference
 ref_s3fifo = S3FIFO(cache_size=1024, small_size_ratio=0.1, ghost_size_ratio=0.9, move_to_main_threshold=2)
 
 # for req in reader:

examples/trace_analysis.py

@@ -1,12 +1,10 @@
 import libcachesim as lcs
 
 # Step 1: Get one trace from S3 bucket
-URI = "cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"
-dl = lcs.DataLoader()
-dl.load(URI)
+URI = "s3://cache-datasets/cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"
 
 reader = lcs.TraceReader(
-    trace=dl.get_cache_path(URI),
+    trace=URI,
     trace_type=lcs.TraceType.ORACLE_GENERAL_TRACE,
     reader_init_params=lcs.ReaderInitParam(ignore_obj_size=False),
 )

src/exception.cpp

@@ -21,9 +21,9 @@ void register_exception(py::module& m) {
     try {
       if (p) std::rethrow_exception(p);
     } catch (const CacheException& e) {
-      exc_cache(e.what());
+      py::set_error(exc_cache, e.what());
     } catch (const ReaderException& e) {
-      exc_reader(e.what());
+      py::set_error(exc_reader, e.what());
     }
   });