Ijar: extract [] to platform_utils

zip_main.cc no longer needs <unistd.h>.
This change takes us closer to compiling ijar,
thus Bazel, with MSVC.

See #2157
See #2107

--
MOS_MIGRATED_REVID=140723658

third_party/ijar/platform_utils.cc

@@ -29,6 +29,8 @@
 
 namespace devtools_ijar {
 
+using std::string;
+
 bool stat_file(const char* path, Stat* result) {
 #ifdef COMPILER_MSVC
   // TODO(laszlocsomor) 2016-12-01: implement this and other methods, in order
@@ -113,4 +115,21 @@ bool read_file(const char* path, void* buffer, size_t size) {
 #endif  // COMPILER_MSVC
 }
 
+string get_cwd() {
+#ifdef COMPILER_MSVC
+  // TODO(laszlocsomor) 2016-12-01: implement this and other methods, in order
+  // to close https://github.com/bazelbuild/bazel/issues/2157.
+  fprintf(stderr, "Not yet implemented on Windows\n");
+  return "";
+#else   // not COMPILER_MSVC
+  char cwd[PATH_MAX];
+  if (getcwd(cwd, PATH_MAX) == NULL) {
+    fprintf(stderr, "getcwd() failed: %s\n", strerror(errno));
+    return "";
+  } else {
+    return string(cwd);
+  }
+#endif  // COMPILER_MSVC
+}
+
 }  // namespace devtools_ijar

third_party/ijar/platform_utils.h

@@ -49,6 +49,10 @@ bool write_file(const char* path, mode_t perm, const void* data, size_t size);
 // Returns false upon failure and reports the error to stderr.
 bool read_file(const char* path, void* buffer, size_t size);
 
+// Returns the current working directory.
+// Returns the empty string upon failure and reports the error to stderr.
+std::string get_cwd();
+
 }  // namespace devtools_ijar
 
 #endif  // THIRD_PARTY_IJAR_PLATFORM_UTILS_H_

third_party/ijar/zip_main.cc

@@ -26,7 +26,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 
 #include <memory>
 #include <set>
@@ -161,17 +160,16 @@ void basename(const char *path, char *output, size_t output_size) {
 // Execute the extraction (or just listing if just v is provided)
 int extract(char *zipfile, char* exdir, char **files, bool verbose,
             bool extract) {
-  char cwd[PATH_MAX];
-  if (getcwd(cwd, PATH_MAX) == NULL) {
-    fprintf(stderr, "getcwd() failed: %s.\n", strerror(errno));
+  std::string cwd = get_cwd();
+  if (cwd.empty()) {
     return -1;
   }
 
   char output_root[PATH_MAX];
   if (exdir != NULL) {
-    concat_path(output_root, PATH_MAX, cwd, exdir);
+    concat_path(output_root, PATH_MAX, cwd.c_str(), exdir);
   } else {
-    strncpy(output_root, cwd, PATH_MAX);
+    strncpy(output_root, cwd.c_str(), PATH_MAX);
   }
 
   UnzipProcessor processor(output_root, files, verbose, extract);