[ion/clipboard] Rework clipboard handling

Change the way the clipboard is fetched, so as to preserve the
Poincare/Python translation feature, and remove the cap on the length of
text being imported into the simulator.

Change-Id: I0f3e83c0c8aa4b64eb08d882aa6891b31f191e22

build/toolchain.emscripten.mak

@@ -105,7 +105,12 @@ _mp_hal_input \
 _mp_import_name \
 _mp_parse_compile_execute \
 _get_clipboard_text \
+_set_clipboard_text \
+__ZN3Ion9Clipboard24fetchFromSystemClipboardEPcm \
+__ZN3Ion9Clipboard21sendToSystemClipboardEPKc \
 __ZN3Ion9Clipboard4readEPcm \
+__ZN3Ion9Clipboard5writeEPKc \
+__ZN9Clipboard5storeEPKci \
 __ZN9Clipboard10storedTextEv \
 __ZN11LayoutField18privateHandleEventEN3Ion6Events5EventE \
 __ZN11LayoutField11handleEventEN3Ion6Events5EventE \

escher/src/clipboard.cpp

@@ -15,7 +15,10 @@ void Clipboard::store(const char * storedText, int length) {
 }
 
 const char * Clipboard::storedText() {
-  Ion::Clipboard::read(m_textBuffer, TextField::maxBufferSize());
+  const char * systemText = Ion::Clipboard::read();
+  if (systemText) {
+    return systemText;
+  }
 
   /* In order to allow copy/paste of empty formulas, we need to add empty
    * layouts between empty system parenthesis. This way, when the expression

ion/include/ion/clipboard.h

@@ -1,16 +1,15 @@
 #ifndef ION_CLIPBOARD_H
 #define ION_CLIPBOARD_H
 
-#include <stddef.h>
-
 namespace Ion {
 namespace Clipboard {
 
 /* Write the text to the system clipboard. */
 void write(const char * text);
 
-/* Fill the buffer with text from the system clipboard. */
-void read(char * buffer, size_t bufferSize);
+/* Returns the system's clipboard text if it differs from the text previously
+ * copied, and nullptr otherwise. */
+const char * read();
 
 }
 }

ion/src/device/shared/drivers/clipboard.cpp

@@ -6,6 +6,6 @@ namespace Ion {
  * On the device, the clipboard is fully handled by Escher::Clipboard. */
 
 void Clipboard::write(const char * text) {}
-void Clipboard::read(char * buffer, size_t bufferSize) {}
+const char * Clipboard::read() { return nullptr; }
 
 }

ion/src/simulator/Makefile

@@ -8,6 +8,7 @@ ion_src += $(addprefix ion/src/simulator/shared/, \
   dummy/serial_number.cpp \
   dummy/stack.cpp \
   dummy/usb.cpp \
+  clipboard.cpp \
   console_stdio.cpp:-consoledisplay \
   crc32.cpp \
   display.cpp:-headless \

ion/src/simulator/android/Makefile

@@ -6,7 +6,7 @@ ion_src += $(addprefix ion/src/simulator/android/src/cpp/, \
 ion_src += $(addprefix ion/src/simulator/shared/, \
   dummy/callback.cpp \
   dummy/language.cpp \
-  clipboard.cpp \
+  clipboard_helper.cpp \
   haptics.cpp \
 )
 

ion/src/simulator/ios/Makefile

@@ -6,7 +6,7 @@ ion_src += $(addprefix ion/src/simulator/shared/, \
   apple/language.m \
   dummy/callback.cpp \
   dummy/haptics_enabled.cpp \
-  clipboard.cpp \
+  clipboard_helper.cpp \
   haptics.cpp \
 )
 

ion/src/simulator/linux/Makefile

@@ -16,7 +16,7 @@ ion_src += $(addprefix ion/src/simulator/linux/, \
 ion_src += $(addprefix ion/src/simulator/shared/, \
   dummy/callback.cpp \
   dummy/haptics_enabled.cpp \
-  clipboard.cpp \
+  clipboard_helper.cpp \
   collect_registers_x86_64.s \
   collect_registers.cpp \
   haptics.cpp \

ion/src/simulator/macos/Makefile

@@ -6,7 +6,7 @@ ion_src += $(addprefix ion/src/simulator/shared/, \
   apple/language.m \
   dummy/callback.cpp \
   dummy/haptics_enabled.cpp \
-  clipboard.cpp \
+  clipboard_helper.cpp \
   collect_registers_x86_64.s \
   collect_registers.cpp \
   haptics.cpp \

ion/src/simulator/shared/clipboard.cpp

@@ -1,27 +1,33 @@
 #include <ion/clipboard.h>
-#include <SDL.h>
+#include "clipboard_helper.h"
+#include <ion.h>
 #include <string.h>
 
-/* This file implements the methods to access the system clipboard on all
- * targets but the web simulator. */
-
 namespace Ion {
+namespace Clipboard {
 
-void Clipboard::write(const char * text) {
+uint32_t localClipboardVersion;
+
+void write(const char * text) {
   /* FIXME : Handle the error if need be. */
-  SDL_SetClipboardText(text);
+  sendToSystemClipboard(text);
+  localClipboardVersion = crc32Byte(reinterpret_cast<const uint8_t *>(text), strlen(text));
 }
 
-void Clipboard::read(char * buffer, size_t bufferSize) {
-  if (!SDL_HasClipboardText()) {
-    buffer[0] = '\0';
-    return;
+const char * read() {
+  constexpr size_t bufferSize = 32768;
+  static char buffer[bufferSize];
+  fetchFromSystemClipboard(buffer, bufferSize);
+  if (buffer[0] == '\0') {
+    return nullptr;
   }
-  char * text = SDL_GetClipboardText();
-  if (text) {
-    strlcpy(buffer, text, bufferSize);
-    SDL_free(text);
+
+  uint32_t version = crc32Byte(reinterpret_cast<const uint8_t *>(buffer), strlen(buffer));
+  if (version == localClipboardVersion) {
+    return nullptr;
   }
+  return buffer;
 }
 
 }
+}

ion/src/simulator/shared/clipboard_helper.cpp

@@ -0,0 +1,28 @@
+#include "clipboard_helper.h"
+#include <SDL.h>
+#include <string.h>
+
+namespace Ion {
+namespace Clipboard {
+
+void sendToSystemClipboard(const char * text) {
+  SDL_SetClipboardText(text);
+}
+
+void fetchFromSystemClipboard(char * buffer, size_t bufferSize) {
+  if (!SDL_HasClipboardText()) {
+    buffer[0] = '\0';
+    return;
+  }
+  char * text = SDL_GetClipboardText();
+  if (text) {
+    strlcpy(buffer, text, bufferSize);
+  } else {
+    buffer[0] = '\0';
+  }
+  SDL_free(text);
+
+}
+
+}
+}

ion/src/simulator/shared/clipboard_helper.h

@@ -0,0 +1,15 @@
+#ifndef ION_CLIPBOARD_HELPER_H
+#define ION_CLIPBOARD_HELPER_H
+
+#include <stddef.h>
+
+namespace Ion {
+namespace Clipboard {
+
+void sendToSystemClipboard(const char * text);
+void fetchFromSystemClipboard(char * buffer, size_t bufferSize);
+
+}
+}
+
+#endif

ion/src/simulator/web/Makefile

@@ -15,7 +15,7 @@ LDFLAGS += --pre-js ion/src/simulator/web/preamble_env.js
 
 ion_src += $(addprefix ion/src/simulator/web/, \
   callback.cpp \
-  clipboard.cpp \
+  clipboard_helper.cpp \
   helpers.cpp \
 )
 

ion/src/simulator/web/clipboard_helper.cpp

@@ -1,4 +1,4 @@
-#include <ion/clipboard.h>
+#include "../shared/clipboard_helper.h"
 #include <emscripten.h>
 #include <SDL.h>
 #include <assert.h>
@@ -48,20 +48,17 @@ EM_JS(void, get_clipboard_text, (char * buffer, uint32_t bufferSize, AsyncStatus
 });
 
 namespace Ion {
+namespace Clipboard {
 
-void Clipboard::write(const char * text) {
-  /* FIXME : Handle the error if need be. */
+void sendToSystemClipboard(const char * text) {
   /* As the rest of the execution does not depend on the system clipboard being
    * properly filled at this point, the call to set_clipboard_text does not
    * need to be made synchronous. */
   AsyncStatus lock;
   set_clipboard_text(text, &lock, AsyncStatus::Failure, AsyncStatus::Success);
-  /* Store a local copy of the text in case the browser does not grant access
-   * to the clipboard. */
-  SDL_SetClipboardText(text);
 }
 
-void Clipboard::read(char * buffer, size_t bufferSize) {
+void fetchFromSystemClipboard(char * buffer, size_t bufferSize) {
   AsyncStatus lock = AsyncStatus::Pending;
   static_assert(sizeof(size_t) <= sizeof(uint32_t), "Cast from size_t to uint32_t may overflow.");
   get_clipboard_text(buffer, static_cast<uint32_t>(bufferSize), &lock, AsyncStatus::Failure, AsyncStatus::Success);
@@ -71,17 +68,7 @@ void Clipboard::read(char * buffer, size_t bufferSize) {
   if (lock == AsyncStatus::Success) {
     return;
   }
-  /* If the browser does not grant access to the clipboard, read from a local
-   * copy to at least maintain the basic copy-paste functionnality. */
-  if (!SDL_HasClipboardText()) {
-    buffer[0] = '\0';
-    return;
-  }
-  char * text = SDL_GetClipboardText();
-  if (text) {
-    strlcpy(buffer, text, bufferSize);
-    SDL_free(text);
-  }
 }
 
 }
+}

ion/src/simulator/windows/Makefile

@@ -7,7 +7,7 @@ ion_src += $(addprefix ion/src/simulator/windows/, \
 ion_src += $(addprefix ion/src/simulator/shared/, \
   dummy/callback.cpp \
   dummy/haptics_enabled.cpp \
-  clipboard.cpp \
+  clipboard_helper.cpp \
   haptics.cpp \
 )