Add command line parameter --no-heap-copy that optimizes for small memory footprint and fread() performance over the default behavior that copied VFS to HEAP, that is designed for mmap() performance.

Adjust MEMFS node contentMode enum to reflect whether content is off the main HEAP or not. Note that this enum is not much used, so this has little effect. Add browser tests to check that fread() and mmap() work with and without --no-heap-copy.

3 files changed, 42 insertions, 23 deletions

diff --git a/tests/mmap_file.c b/tests/mmap_file.c
new file mode 100644
index 00000000..6eed95e0
--- /dev/null
+++ b/tests/mmap_file.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <sys/mman.h>
+#include <emscripten.h>
+#include <string.h>
+#include <assert.h>
+
+int main() {
+    printf("*\n");
+    FILE *f = fopen("data.dat", "r");
+    char *m;
+    m = (char*)mmap(NULL, 9000, PROT_READ, MAP_PRIVATE, fileno(f), 0);
+    for (int i = 0; i < 20; i++) putchar(m[i]);
+    assert(!strncmp(m, "data from the file .", 20));
+    munmap(m, 9000);
+    printf("\n");
+    m = (char*)mmap(NULL, 9000, PROT_READ, MAP_PRIVATE, fileno(f), 5);
+    for (int i = 0; i < 20; i++) putchar(m[i]);
+    assert(!strncmp(m, "from the file ......", 20));
+    munmap(m, 9000);
+    printf("\n*\n");
+
+#ifdef REPORT_RESULT
+    int result = 1;
+    REPORT_RESULT();
+#endif
+    return 0;
+}
diff --git a/tests/test_browser.py b/tests/test_browser.py
index 2ff9106b..d52f109f 100644
--- a/tests/test_browser.py
+++ b/tests/test_browser.py
@@ -338,7 +338,7 @@ If manually bisecting:
       ("somefile.txt@/directory/file.txt", "/directory/file.txt"),
       ("somefile.txt@/directory/file.txt", "directory/file.txt"),
       (absolute_src_path + "@/directory/file.txt", "directory/file.txt")]
-    
+
     for test in test_cases:
       (srcpath, dstpath) = test
       print 'Testing', srcpath, dstpath
@@ -346,6 +346,11 @@ If manually bisecting:
       Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'main.cpp'), '--preload-file', srcpath, '-o', 'page.html']).communicate()
       self.run_browser('page.html', 'You should see |load me right before|.', '/report_result?1')
 
+    # Test that '--no-heap-copy' works.
+    make_main('somefile.txt')
+    Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'main.cpp'), '--preload-file', 'somefile.txt', '--no-heap-copy', '-o', 'page.html']).communicate()
+    self.run_browser('page.html', 'You should see |load me right before|.', '/report_result?1')
+
     # By absolute path
 
     make_main('somefile.txt') # absolute becomes relative
@@ -1566,3 +1571,7 @@ keydown(100);keyup(100); // trigger the end
     Popen([PYTHON, EMCC, path_from_root('tests', 'browser_module.cpp'), '-o', 'module.js', '-O2', '-s', 'SIDE_MODULE=1', '-s', 'DLOPEN_SUPPORT=1', '-s', 'EXPORTED_FUNCTIONS=["_one", "_two"]']).communicate()
     self.btest('browser_main.cpp', args=['-O2', '-s', 'MAIN_MODULE=1', '-s', 'DLOPEN_SUPPORT=1'], expected='8')
 
+  def test_mmap_file(self):
+    open(self.in_dir('data.dat'), 'w').write('data from the file ' + ('.' * 9000))
+    for extra_args in [[], ['--no-heap-copy']]:
+      self.btest(path_from_root('tests', 'mmap_file.c'), expected='1', args=['--preload-file', 'data.dat'] + extra_args)
diff --git a/tests/test_core.py b/tests/test_core.py
index b421659c..89dd725f 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -8594,30 +8594,13 @@ void*:16
 
   def test_mmap_file(self):
     if self.emcc_args is None: return self.skip('requires emcc')
-    self.emcc_args += ['--embed-file', 'data.dat']
+    for extra_args in [[], ['--no-heap-copy']]:
+      self.emcc_args += ['--embed-file', 'data.dat'] + extra_args
 
-    open(self.in_dir('data.dat'), 'w').write('data from the file ' + ('.' * 9000))
+      open(self.in_dir('data.dat'), 'w').write('data from the file ' + ('.' * 9000))
 
-    src = r'''
-      #include <stdio.h>
-      #include <sys/mman.h>
-
-      int main() {
-        printf("*\n");
-        FILE *f = fopen("data.dat", "r");
-        char *m;
-        m = (char*)mmap(NULL, 9000, PROT_READ, MAP_PRIVATE, fileno(f), 0);
-        for (int i = 0; i < 20; i++) putchar(m[i]);
-        munmap(m, 9000);
-        printf("\n");
-        m = (char*)mmap(NULL, 9000, PROT_READ, MAP_PRIVATE, fileno(f), 5);
-        for (int i = 0; i < 20; i++) putchar(m[i]);
-        munmap(m, 9000);
-        printf("\n*\n");
-        return 0;
-      }
-    '''
-    self.do_run(src, '*\ndata from the file .\nfrom the file ......\n*\n')
+      src = open(path_from_root('tests', 'mmap_file.c')).read()
+      self.do_run(src, '*\ndata from the file .\nfrom the file ......\n*\n')
 
   def test_cubescript(self):
     if self.emcc_args is None: return self.skip('requires emcc')