DevFS initial implementation

runtime/vm/dev_fs.cc

Index: runtime/vm/dev_fs.cc
diff --git a/runtime/vm/dev_fs.cc b/runtime/vm/dev_fs.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6a9a76c62c381f7d8f18320de531f4b710f8a52e
--- /dev/null
+++ b/runtime/vm/dev_fs.cc
@@ -0,0 +1,370 @@
+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "vm/dev_fs.h"
+
+#include "vm/hash_table.h"
+#include "vm/json_stream.h"
+#include "vm/lockers.h"
+#include "vm/object.h"
+#include "vm/unicode.h"
+
+namespace dart {
+
+static const uint8_t decode_table[256] = {
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
+  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
+  64,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+  15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
+  64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+  41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+  64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
+};
+
+class Base64 {
+ public:
+  static void decode(const char* base64,
+                     std::vector<uint8_t>* output) {
+    ASSERT(output != NULL);
+    ASSERT(base64 != NULL);
+    const intptr_t base64_len = strlen(base64);
+    int b[4];
+    for (intptr_t i = 0; i < base64_len; i += 4) {
+      b[0] = decode_table[static_cast<uint8_t>(base64[i])];
+      b[1] = decode_table[static_cast<uint8_t>(base64[i + 1])];
+      b[2] = decode_table[static_cast<uint8_t>(base64[i + 2])];
+      b[3] = decode_table[static_cast<uint8_t>(base64[i + 3])];
+      output->push_back((b[0] << 2) | (b[1] >> 4));
+      if (b[2] < 64) {
+        output->push_back((b[1] << 4) | (b[2] >> 2));
+        if (b[3] < 64)  {
+          output->push_back((b[2] << 6) | b[3]);
+        }
+      }
+    }
+  }
+};
+
+
+class FileSystem {
+ public:
+  explicit FileSystem(const std::string& name)
+    : name_(name) {
+  }
+
+  ~FileSystem() {
+  }
+
+  bool ReadFile(const std::string& path,
+                std::vector<uint8_t>** file_contents) {
+    *file_contents = NULL;
+    std::map<std::string, std::vector<uint8_t>*>::iterator iter;
+    iter = files_.find(path);
+    if (iter == files_.end()) {
+      return false;
+    }
+    *file_contents = iter->second;
+    return true;
+  }
+
+  void DeleteFile(const std::string& path) {
+    std::map<std::string, std::vector<uint8_t>*>::iterator iter;
+    iter = files_.find(path);
+    if (iter == files_.end()) {
+      return;
+    }
+    std::vector<uint8_t>* contents = iter->second;
+    files_.erase(iter);
+    delete contents;
+  }
+
+  void WriteFile(const std::string& path,
+                 const char* file_contents) {
+    DeleteFile(path);
+    std::vector<uint8_t>* data = new std::vector<uint8_t>();
+    Base64::decode(file_contents, data);
+    files_[path] = data;
+  }
+
+  void ListFiles(JSONStream* js) {
+    JSONObject jsobj(js);
+    jsobj.AddProperty("type", "FSFilesList");
+    JSONArray jsarr(&jsobj, "files");
+    std::map<std::string, std::vector<uint8_t>*>::iterator iter;
+    for (iter = files_.begin(); iter != files_.end(); iter++) {
+      JSONObject file_info(&jsarr);
+      file_info.AddProperty("name", iter->first.c_str());
+      file_info.AddProperty("size", static_cast<int64_t>(iter->second->size()));
+    }
+  }
+
+ private:
+  std::string name_;
+
+  std::map<std::string, std::vector<uint8_t>*> files_;
+};
+
+// Some static state is held outside of the DevFS class so that we don't
+// have to include stl headers in our vm/ headers.
+static std::map<std::string, FileSystem*>* file_systems_;
+
+Mutex* DevFS::mutex_ = NULL;
+
+
+void DevFS::Init() {
+  if (mutex_ != NULL) {
+    // Already initialized.
+    ASSERT(file_systems_ != NULL);
+    return;
+  }
+  mutex_ = new Mutex();
+  file_systems_ = new std::map<std::string, FileSystem*>();
+  ASSERT(mutex_ != NULL);
+  ASSERT(file_systems_ != NULL);
+}
+
+
+void DevFS::Cleanup() {
+  delete mutex_;
+  mutex_ = NULL;
+  std::map<std::string, FileSystem*>::iterator iter;
+  for (iter = file_systems_->begin(); iter != file_systems_->end(); iter++) {
+    FileSystem* fs = iter->second;
+    delete fs;
+  }
+  delete file_systems_;
+  file_systems_ = NULL;
+}
+
+
+void DevFS::ListFileSystems(JSONStream* js) {
+  SafepointMutexLocker ml(mutex_);
+  JSONObject jsobj(js);
+  jsobj.AddProperty("type", "FSList");
+  JSONArray jsarr(&jsobj, "fsNames");
+
+  std::map<std::string, FileSystem*>::iterator iter;
+  for (iter = file_systems_->begin(); iter != file_systems_->end(); iter++) {
+    const std::string& key = iter->first;
+    jsarr.AddValue(key.c_str());
+  }
+}
+
+
+FileSystem* DevFS::LookupFileSystem(const char* fs_name) {
+  std::string key = std::string(fs_name);
+  std::map<std::string, FileSystem*>::iterator iter;
+  iter = file_systems_->find(key);
+  if (iter != file_systems_->end()) {
+    return iter->second;
+  }
+  return NULL;
+}
+
+
+FileSystem* DevFS::LookupFileSystem(const String& fs_name) {
+  return LookupFileSystem(fs_name.ToCString());
+}
+
+
+void DevFS::CreateFileSystem(JSONStream* js, const String& fs_name) {
+  SafepointMutexLocker ml(mutex_);
+  // TODO(turnidge): Ensure that fs_name is a legal URI host value, i.e. ascii.
+  if (LookupFileSystem(fs_name) != NULL) {
+    js->PrintError(kFileSystemAlreadyExists,
+                   "%s: file system '%s' already exists",
+                   js->method(), fs_name.ToCString());
+    return;
+  }
+
+  std::string key = std::string(fs_name.ToCString());
+  FileSystem* file_system = new FileSystem(key);
+  (*file_systems_)[key] = file_system;
+
+  JSONObject jsobj(js);
+  jsobj.AddProperty("type", "Success");
+}
+
+
+void DevFS::DeleteFileSystem(JSONStream* js, const String& fs_name) {
+  SafepointMutexLocker ml(mutex_);
+  FileSystem* file_system = LookupFileSystem(fs_name);
+  if (file_system == NULL) {
+    js->PrintError(kFileSystemDoesNotExist,
+                   "%s: file system '%s' does not exist",
+                   js->method(), fs_name.ToCString());
+    return;
+  }
+  std::string key = std::string(fs_name.ToCString());
+  file_systems_->erase(key);
+  delete file_system;
+  JSONObject jsobj(js);
+  jsobj.AddProperty("type", "Success");
+}
+
+
+void DevFS::ListFiles(JSONStream* js, const String& fs_name) {
+  SafepointMutexLocker ml(mutex_);
+  FileSystem* file_system = LookupFileSystem(fs_name);
+  if (file_system == NULL) {
+    js->PrintError(kFileSystemDoesNotExist,
+                   "%s: file system '%s' does not exist",
+                   js->method(), fs_name.ToCString());
+    return;
+  }
+
+  file_system->ListFiles(js);
+}
+
+
+static void PrintWriteFilesError(JSONStream* js,
+                                 intptr_t i) {
+  js->PrintError(kInvalidParams,
+                 "%s: files array invalid at index '%" Pd "'",
+                 js->method(), i);
+}
+
+
+void DevFS::WriteFiles(JSONStream* js,
+                       const String& fs_name,
+                       const Array& files) {
+  SafepointMutexLocker ml(mutex_);
+  FileSystem* file_system = LookupFileSystem(fs_name);
+  if (file_system == NULL) {
+    js->PrintError(kFileSystemDoesNotExist,
+                   "%s: file system '%s' does not exist",
+                   js->method(), fs_name.ToCString());
+    return;
+  }
+
+  Object& test = Object::Handle();
+  GrowableObjectArray& file_info = GrowableObjectArray::Handle();
+  String& path = String::Handle();
+  String& file_contents = String::Handle();
+
+  // First, validate the array of files is properly formed.
+  for (intptr_t i = 0; i < files.Length(); i++) {
+    test = files.At(i);
+    if (!test.IsGrowableObjectArray()) {
+      PrintWriteFilesError(js, i);
+      return;
+    }
+    file_info ^= test.raw();
+    if (file_info.Length() != 2) {
+      PrintWriteFilesError(js, i);
+      return;
+    }
+    test = file_info.At(0);
+    if (!test.IsString()) {
+      PrintWriteFilesError(js, i);
+      return;
+    }
+    std::string key = std::string(String::Cast(test).ToCString());
+    if ((key.size() == 0) || (key[0] != '/')) {
+      js->PrintError(kInvalidParams,
+                     "%s: file system path '%s' must begin with a /",
+                     js->method(), String::Cast(test).ToCString());
+      return;
+    }
+    test = file_info.At(1);
+    if (!test.IsString()) {
+      PrintWriteFilesError(js, i);
+      return;
+    }
+  }
+
+  // Now atomically update the file system.
+  for (intptr_t i = 0; i < files.Length(); i++) {
+    file_info = GrowableObjectArray::RawCast(files.At(i));
+    path = String::RawCast(file_info.At(0));
+    file_contents = String::RawCast(file_info.At(1));
+    file_system->WriteFile(path.ToCString(),
+                           file_contents.ToCString());
+  }
+
+  JSONObject jsobj(js);
+  jsobj.AddProperty("type", "Success");
+}
+
+
+void DevFS::WriteFile(JSONStream* js,
+                      const String& fs_name,
+                      const String& path,
+                      const String& file_contents) {
+  SafepointMutexLocker ml(mutex_);
+  FileSystem* file_system = LookupFileSystem(fs_name);
+  if (file_system == NULL) {
+    js->PrintError(kFileSystemDoesNotExist,
+                   "%s: file system '%s' does not exist",
+                   js->method(), fs_name.ToCString());
+    return;
+  }
+
+  std::string key = std::string(path.ToCString());
+  if ((key.size() == 0) || (key[0] != '/')) {
+    js->PrintError(kInvalidParams,
+                   "%s: file system path '%s' must begin with a /",
+                   js->method(), path.ToCString());
+    return;
+  }
+
+  file_system->WriteFile(path.ToCString(),
+                         file_contents.ToCString());
+
+  JSONObject jsobj(js);
+  jsobj.AddProperty("type", "Success");
+}
+
+
+void DevFS::ReadFile(JSONStream* js,
+                     const String& fs_name,
+                     const String& path) {
+  SafepointMutexLocker ml(mutex_);
+  FileSystem* file_system = LookupFileSystem(fs_name);
+  if (file_system == NULL) {
+    js->PrintError(kFileSystemDoesNotExist,
+                   "%s: file system '%s' does not exist",
+                   js->method(), fs_name.ToCString());
+    return;
+  }
+
+  std::string key = std::string(path.ToCString());
+  if ((key.size() == 0) || (key[0] != '/')) {
+    js->PrintError(kInvalidParams,
+                   "%s: file system path '%s' must begin with a /",
+                   js->method(), path.ToCString());
+    return;
+  }
+  std::vector<uint8_t>* file_contents;
+
+  bool success = file_system->ReadFile(key, &file_contents);
+
+  if (!success) {
+    js->PrintError(kFileDoesNotExist,
+                   "%s: file 'dart-devfs://%s/%s' does not exist",
+                   js->method(), fs_name.ToCString(), path.ToCString());
+    return;
+  }
+
+  JSONObject jsobj(js);
+  jsobj.AddProperty("type", "FSFile");
+  jsobj.AddPropertyBase64("fileContents",
+                          &((*file_contents)[0]),
+                          file_contents->size());
+}
+
+}  // namespace dart