Consolidate code for getting platform details into one place

Makefile

@@ -59,7 +59,7 @@ C = $(wildcard *.c) $(wildcard *.cpp)
 INCLUDES = -I/usr/local/include -I. -Iclipper2/include
 LIBS = -L/usr/local/lib
 
-tippecanoe: geojson.o jsonpull/jsonpull.o tile.o pool.o mbtiles.o geometry.o projection.o memfile.o mvt.o serial.o main.o text.o dirtiles.o pmtiles_file.o plugin.o read_json.o write_json.o geobuf.o flatgeobuf.o evaluator.o geocsv.o csv.o geojson-loop.o json_logger.o visvalingam.o compression.o clip.o sort.o attribute.o thread.o shared_borders.o clipper2/src/clipper.engine.o
+tippecanoe: geojson.o jsonpull/jsonpull.o tile.o pool.o mbtiles.o geometry.o projection.o memfile.o mvt.o serial.o main.o platform.o text.o dirtiles.o pmtiles_file.o plugin.o read_json.o write_json.o geobuf.o flatgeobuf.o evaluator.o geocsv.o csv.o geojson-loop.o json_logger.o visvalingam.o compression.o clip.o sort.o attribute.o thread.o shared_borders.o clipper2/src/clipper.engine.o
 	$(CXX) $(PG) $(LIBS) $(FINAL_FLAGS) $(CXXFLAGS) -o $@ $^ $(LDFLAGS) -lm -lz -lsqlite3 -lpthread
 
 tippecanoe-enumerate: enumerate.o
@@ -68,7 +68,7 @@ tippecanoe-enumerate: enumerate.o
 tippecanoe-decode: decode.o projection.o mvt.o write_json.o text.o jsonpull/jsonpull.o dirtiles.o pmtiles_file.o
 	$(CXX) $(PG) $(LIBS) $(FINAL_FLAGS) $(CXXFLAGS) -o $@ $^ $(LDFLAGS) -lm -lz -lsqlite3
 
-tile-join: tile-join.o projection.o mbtiles.o mvt.o memfile.o dirtiles.o jsonpull/jsonpull.o text.o evaluator.o csv.o write_json.o pmtiles_file.o clip.o attribute.o thread.o read_json.o clipper2/src/clipper.engine.o
+tile-join: tile-join.o platform.o projection.o mbtiles.o mvt.o memfile.o dirtiles.o jsonpull/jsonpull.o text.o evaluator.o csv.o write_json.o pmtiles_file.o clip.o attribute.o thread.o read_json.o clipper2/src/clipper.engine.o
 	$(CXX) $(PG) $(LIBS) $(FINAL_FLAGS) $(CXXFLAGS) -o $@ $^ $(LDFLAGS) -lm -lz -lsqlite3 -lpthread
 
 tippecanoe-json-tool: jsontool.o jsonpull/jsonpull.o csv.o text.o geojson-loop.o

main.cpp

@@ -21,7 +21,6 @@
 #include <limits.h>
 #include <sqlite3.h>
 #include <stdarg.h>
-#include <sys/resource.h>
 #include <pthread.h>
 #include <getopt.h>
 #include <signal.h>
@@ -67,6 +66,7 @@
 #include "sort.hpp"
 #include "attribute.hpp"
 #include "thread.hpp"
+#include "platform.hpp"
 
 static int low_detail = 12;
 static int full_detail = -1;
@@ -187,7 +187,7 @@ void init_cpus() {
 	if (TIPPECANOE_MAX_THREADS != NULL) {
 		CPUS = atoi_require(TIPPECANOE_MAX_THREADS, "TIPPECANOE_MAX_THREADS");
 	} else {
-		CPUS = sysconf(_SC_NPROCESSORS_ONLN);
+		CPUS = get_num_avail_cpus();
 	}
 
 	if (CPUS < 1) {
@@ -202,13 +202,7 @@ void init_cpus() {
 	// Round down to a power of 2
 	CPUS = 1 << (int) (log(CPUS) / log(2));
 
-	struct rlimit rl;
-	if (getrlimit(RLIMIT_NOFILE, &rl) != 0) {
-		perror("getrlimit");
-		exit(EXIT_PTHREAD);
-	} else {
-		MAX_FILES = rl.rlim_cur;
-	}
+	MAX_FILES = get_max_open_files();
 
 	// Don't really want too many temporary files, because the file system
 	// will start to bog down eventually
@@ -222,7 +216,7 @@ void init_cpus() {
 	long long fds[MAX_FILES];
 	long long i;
 	for (i = 0; i < MAX_FILES; i++) {
-		fds[i] = open("/dev/null", O_RDONLY | O_CLOEXEC);
+		fds[i] = open(get_null_device(), O_RDONLY | O_CLOEXEC);
 		if (fds[i] < 0) {
 			break;
 		}
@@ -899,7 +893,7 @@ void radix1(int *geomfds_in, int *indexfds_in, int inputs, int prefix, int split
 				std::atomic<long long> indexpos(indexst.st_size);
 				int bytes = sizeof(struct index);
 
-				int page = sysconf(_SC_PAGESIZE);
+				int page = get_page_size();
 				// Don't try to sort more than 2GB at once,
 				// which used to crash Macs and may still
 				long long max_unit = 2LL * 1024 * 1024 * 1024;
@@ -1069,31 +1063,6 @@ void prep_drop_states(struct drop_state *ds, int maxzoom, int basezoom, double d
 	}
 }
 
-static size_t calc_memsize() {
-	size_t mem;
-
-#ifdef __APPLE__
-	int64_t hw_memsize;
-	size_t len = sizeof(int64_t);
-	if (sysctlbyname("hw.memsize", &hw_memsize, &len, NULL, 0) < 0) {
-		perror("sysctl hw.memsize");
-		exit(EXIT_MEMORY);
-	}
-	mem = hw_memsize;
-#else
-	long long pagesize = sysconf(_SC_PAGESIZE);
-	long long pages = sysconf(_SC_PHYS_PAGES);
-	if (pages < 0 || pagesize < 0) {
-		perror("sysconf _SC_PAGESIZE or _SC_PHYS_PAGES");
-		exit(EXIT_MEMORY);
-	}
-
-	mem = (long long) pages * pagesize;
-#endif
-
-	return mem;
-}
-
 void radix(std::vector<struct reader> &readers, int nreaders, FILE *geomfile, FILE *indexfile, const char *tmpdir, std::atomic<long long> *geompos, int maxzoom, int basezoom, double droprate, double gamma) {
 	// Run through the index and geometry for each reader,
 	// splitting the contents out by index into as many
@@ -1446,7 +1415,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 	size_t dist_count = 0;
 	double area_sum = 0;
 
-	int files_open_before_reading = open("/dev/null", O_RDONLY | O_CLOEXEC);
+	int files_open_before_reading = open(get_null_device(), O_RDONLY | O_CLOEXEC);
 	if (files_open_before_reading < 0) {
 		perror("open /dev/null");
 		exit(EXIT_OPEN);
@@ -1887,7 +1856,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 		}
 	}
 
-	int files_open_after_reading = open("/dev/null", O_RDONLY | O_CLOEXEC);
+	int files_open_after_reading = open(get_null_device(), O_RDONLY | O_CLOEXEC);
 	if (files_open_after_reading < 0) {
 		perror("open /dev/null");
 		exit(EXIT_OPEN);
@@ -3728,7 +3697,7 @@ int main(int argc, char **argv) {
 
 	signal(SIGPIPE, SIG_IGN);
 
-	files_open_at_start = open("/dev/null", O_RDONLY | O_CLOEXEC);
+	files_open_at_start = open(get_null_device(), O_RDONLY | O_CLOEXEC);
 	if (files_open_at_start < 0) {
 		perror("open /dev/null");
 		exit(EXIT_OPEN);
@@ -3878,7 +3847,7 @@ int main(int argc, char **argv) {
 	muntrace();
 #endif
 
-	i = open("/dev/null", O_RDONLY | O_CLOEXEC);
+	i = open(get_null_device(), O_RDONLY | O_CLOEXEC);
 	// i < files_open_at_start is not an error, because reading from a pipe closes stdin
 	if (i > files_open_at_start) {
 		fprintf(stderr, "Internal error: did not close all files: %d\n", i);

platform.cpp

@@ -0,0 +1,56 @@
+#include "platform.hpp"
+#include <cstdlib>
+#include <cstdio>
+#include <unistd.h>
+#include <sys/resource.h>
+
+#if defined(__APPLE__) || defined(__FreeBSD__)
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <sys/param.h>
+#include <sys/mount.h>
+#endif
+
+#include "errors.hpp"
+
+long get_num_avail_cpus() {
+	return sysconf(_SC_NPROCESSORS_ONLN);
+}
+
+long get_page_size() {
+	return sysconf(_SC_PAGESIZE);
+}
+
+size_t calc_memsize() {
+	size_t mem;
+
+#ifdef __APPLE__
+	int64_t hw_memsize;
+	size_t len = sizeof(int64_t);
+	if (sysctlbyname("hw.memsize", &hw_memsize, &len, NULL, 0) < 0) {
+		perror("sysctl hw.memsize");
+		exit(EXIT_MEMORY);
+	}
+	mem = hw_memsize;
+#else
+	long long pagesize = sysconf(_SC_PAGESIZE);
+	long long pages = sysconf(_SC_PHYS_PAGES);
+	if (pages < 0 || pagesize < 0) {
+		perror("sysconf _SC_PAGESIZE or _SC_PHYS_PAGES");
+		exit(EXIT_MEMORY);
+	}
+
+	mem = (long long) pages * pagesize;
+#endif
+
+	return mem;
+}
+
+size_t get_max_open_files() {
+	struct rlimit rl;
+	if (getrlimit(RLIMIT_NOFILE, &rl) != 0) {
+		perror("getrlimit");
+		exit(EXIT_PTHREAD);
+	}
+	return rl.rlim_cur;
+}

platform.hpp

@@ -0,0 +1,16 @@
+#ifndef PLATFORM_HPP
+#define PLATFORM_HPP
+
+#include <cstddef>
+
+long get_num_avail_cpus();
+
+long get_page_size();
+
+size_t calc_memsize();
+
+size_t get_max_open_files();
+
+constexpr const char *get_null_device() { return "/dev/null"; }
+
+#endif // PLATFORM_HPP

tile-join.cpp

@@ -43,6 +43,7 @@
 #include "errors.hpp"
 #include "geometry.hpp"
 #include "thread.hpp"
+#include "platform.hpp"
 
 int pk = false;
 int pC = false;
@@ -1199,7 +1200,7 @@ int main(int argc, char **argv) {
 
 	struct tileset_reader *readers = NULL;
 
-	CPUS = sysconf(_SC_NPROCESSORS_ONLN);
+	CPUS = get_num_avail_cpus();
 
 	const char *TIPPECANOE_MAX_THREADS = getenv("TIPPECANOE_MAX_THREADS");
 	if (TIPPECANOE_MAX_THREADS != NULL) {